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android / platform / external / grpc-grpc / 33f139b6e6 / . / src / core / ext / filters / client_channel / lb_policy / xds / xds.cc
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/*
*
* Copyright 2018 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
/// Implementation of the gRPC LB policy.
///
/// This policy takes as input a list of resolved addresses, which must
/// include at least one balancer address.
///
/// An internal channel (\a lb_channel_) is created for the addresses
/// from that are balancers. This channel behaves just like a regular
/// channel that uses pick_first to select from the list of balancer
/// addresses.
///
/// When we get our initial update, we instantiate the internal *streaming*
/// call to the LB server (whichever address pick_first chose). The call
/// will be complete when either the balancer sends status or when we cancel
/// the call (e.g., because we are shutting down). In needed, we retry the
/// call. If we received at least one valid message from the server, a new
/// call attempt will be made immediately; otherwise, we apply back-off
/// delays between attempts.
///
/// We maintain an internal child policy (round_robin) instance for distributing
/// requests across backends. Whenever we receive a new serverlist from
/// the balancer, we update the child policy with the new list of
/// addresses.
///
/// Once a child policy instance is in place (and getting updated as
/// described), calls for a pick, or a cancellation will be serviced right away
/// by forwarding them to the child policy instance. Any time there's no child
/// policy available (i.e., right after the creation of the xDS policy), pick
/// requests are added to a list of pending picks to be flushed and serviced
/// when the child policy instance becomes available.
///
/// \see https://github.com/grpc/grpc/blob/master/doc/load-balancing.md for the
/// high level design and details.
// With the addition of a libuv endpoint, sockaddr.h now includes uv.h when
// using that endpoint. Because of various transitive includes in uv.h,
// including windows.h on Windows, uv.h must be included before other system
// headers. Therefore, sockaddr.h must always be included first.
#include <grpc/support/port_platform.h>
#include "src/core/lib/iomgr/sockaddr.h"
#include "src/core/lib/iomgr/socket_utils.h"
#include <inttypes.h>
#include <limits.h>
#include <string.h>
#include <grpc/byte_buffer_reader.h>
#include <grpc/grpc.h>
#include <grpc/support/alloc.h>
#include <grpc/support/string_util.h>
#include <grpc/support/time.h>
#include "include/grpc/support/alloc.h"
#include "src/core/ext/filters/client_channel/client_channel.h"
#include "src/core/ext/filters/client_channel/lb_policy.h"
#include "src/core/ext/filters/client_channel/lb_policy/xds/xds.h"
#include "src/core/ext/filters/client_channel/lb_policy/xds/xds_channel.h"
#include "src/core/ext/filters/client_channel/lb_policy/xds/xds_client_stats.h"
#include "src/core/ext/filters/client_channel/lb_policy/xds/xds_load_balancer_api.h"
#include "src/core/ext/filters/client_channel/lb_policy_factory.h"
#include "src/core/ext/filters/client_channel/lb_policy_registry.h"
#include "src/core/ext/filters/client_channel/parse_address.h"
#include "src/core/ext/filters/client_channel/resolver/fake/fake_resolver.h"
#include "src/core/ext/filters/client_channel/server_address.h"
#include "src/core/ext/filters/client_channel/service_config.h"
#include "src/core/lib/backoff/backoff.h"
#include "src/core/lib/channel/channel_args.h"
#include "src/core/lib/channel/channel_stack.h"
#include "src/core/lib/gpr/string.h"
#include "src/core/lib/gprpp/manual_constructor.h"
#include "src/core/lib/gprpp/map.h"
#include "src/core/lib/gprpp/memory.h"
#include "src/core/lib/gprpp/orphanable.h"
#include "src/core/lib/gprpp/ref_counted_ptr.h"
#include "src/core/lib/gprpp/sync.h"
#include "src/core/lib/iomgr/combiner.h"
#include "src/core/lib/iomgr/sockaddr.h"
#include "src/core/lib/iomgr/sockaddr_utils.h"
#include "src/core/lib/iomgr/timer.h"
#include "src/core/lib/slice/slice_hash_table.h"
#include "src/core/lib/slice/slice_internal.h"
#include "src/core/lib/slice/slice_string_helpers.h"
#include "src/core/lib/surface/call.h"
#include "src/core/lib/surface/channel.h"
#include "src/core/lib/surface/channel_init.h"
#include "src/core/lib/transport/static_metadata.h"
#define GRPC_XDS_INITIAL_CONNECT_BACKOFF_SECONDS 1
#define GRPC_XDS_RECONNECT_BACKOFF_MULTIPLIER 1.6
#define GRPC_XDS_RECONNECT_MAX_BACKOFF_SECONDS 120
#define GRPC_XDS_RECONNECT_JITTER 0.2
#define GRPC_XDS_DEFAULT_FALLBACK_TIMEOUT_MS 10000
#define GRPC_XDS_MIN_CLIENT_LOAD_REPORTING_INTERVAL_MS 1000
#define GRPC_XDS_DEFAULT_LOCALITY_RETENTION_INTERVAL_MS (15 * 60 * 1000)
#define GRPC_XDS_DEFAULT_FAILOVER_TIMEOUT_MS 10000
namespace grpc_core {
TraceFlag grpc_lb_xds_trace(false, "xds");
namespace {
constexpr char kXds[] = "xds_experimental";
class ParsedXdsConfig : public LoadBalancingPolicy::Config {
public:
ParsedXdsConfig(const char* balancer_name,
RefCountedPtr<LoadBalancingPolicy::Config> child_policy,
RefCountedPtr<LoadBalancingPolicy::Config> fallback_policy)
: balancer_name_(balancer_name),
child_policy_(std::move(child_policy)),
fallback_policy_(std::move(fallback_policy)) {}
const char* name() const override { return kXds; }
const char* balancer_name() const { return balancer_name_; };
RefCountedPtr<LoadBalancingPolicy::Config> child_policy() const {
return child_policy_;
}
RefCountedPtr<LoadBalancingPolicy::Config> fallback_policy() const {
return fallback_policy_;
}
private:
const char* balancer_name_ = nullptr;
RefCountedPtr<LoadBalancingPolicy::Config> child_policy_;
RefCountedPtr<LoadBalancingPolicy::Config> fallback_policy_;
};
class XdsLb : public LoadBalancingPolicy {
public:
explicit XdsLb(Args args);
const char* name() const override { return kXds; }
void UpdateLocked(UpdateArgs args) override;
void ResetBackoffLocked() override;
private:
// Contains a channel to the LB server and all the data related to the
// channel. Holds a ref to the xds policy.
class LbChannelState : public InternallyRefCounted<LbChannelState> {
public:
// An LB call wrapper that can restart a call upon failure. Holds a ref to
// the LB channel. The template parameter is the kind of wrapped LB call.
template <typename T>
class RetryableLbCall : public InternallyRefCounted<RetryableLbCall<T>> {
public:
explicit RetryableLbCall(RefCountedPtr<LbChannelState> lb_chand);
void Orphan() override;
void OnCallFinishedLocked();
T* lb_calld() const { return lb_calld_.get(); }
LbChannelState* lb_chand() const { return lb_chand_.get(); }
private:
void StartNewCallLocked();
void StartRetryTimerLocked();
static void OnRetryTimerLocked(void* arg, grpc_error* error);
// The wrapped LB call that talks to the LB server. It's instantiated
// every time we start a new call. It's null during call retry backoff.
OrphanablePtr<T> lb_calld_;
// The owing LB channel.
RefCountedPtr<LbChannelState> lb_chand_;
// Retry state.
BackOff backoff_;
grpc_timer retry_timer_;
grpc_closure on_retry_timer_;
bool retry_timer_callback_pending_ = false;
bool shutting_down_ = false;
};
// Contains an EDS call to the LB server.
class EdsCallState : public InternallyRefCounted<EdsCallState> {
public:
// The ctor and dtor should not be used directly.
explicit EdsCallState(
RefCountedPtr<RetryableLbCall<EdsCallState>> parent);
~EdsCallState() override;
void Orphan() override;
RetryableLbCall<EdsCallState>* parent() const { return parent_.get(); }
LbChannelState* lb_chand() const { return parent_->lb_chand(); }
XdsLb* xdslb_policy() const { return lb_chand()->xdslb_policy(); }
bool seen_response() const { return seen_response_; }
private:
static void OnResponseReceivedLocked(void* arg, grpc_error* error);
static void OnStatusReceivedLocked(void* arg, grpc_error* error);
bool IsCurrentCallOnChannel() const;
// The owning RetryableLbCall<>.
RefCountedPtr<RetryableLbCall<EdsCallState>> parent_;
bool seen_response_ = false;
// Always non-NULL.
grpc_call* lb_call_;
// recv_initial_metadata
grpc_metadata_array initial_metadata_recv_;
// send_message
grpc_byte_buffer* send_message_payload_ = nullptr;
// recv_message
grpc_byte_buffer* recv_message_payload_ = nullptr;
grpc_closure on_response_received_;
// recv_trailing_metadata
grpc_metadata_array trailing_metadata_recv_;
grpc_status_code status_code_;
grpc_slice status_details_;
grpc_closure on_status_received_;
};
// Contains an LRS call to the LB server.
class LrsCallState : public InternallyRefCounted<LrsCallState> {
public:
// The ctor and dtor should not be used directly.
explicit LrsCallState(
RefCountedPtr<RetryableLbCall<LrsCallState>> parent);
~LrsCallState() override;
void Orphan() override;
void MaybeStartReportingLocked();
RetryableLbCall<LrsCallState>* parent() { return parent_.get(); }
LbChannelState* lb_chand() const { return parent_->lb_chand(); }
XdsLb* xdslb_policy() const { return lb_chand()->xdslb_policy(); }
bool seen_response() const { return seen_response_; }
private:
// Reports client-side load stats according to a fixed interval.
class Reporter : public InternallyRefCounted<Reporter> {
public:
Reporter(RefCountedPtr<LrsCallState> parent,
grpc_millis report_interval)
: parent_(std::move(parent)), report_interval_(report_interval) {
GRPC_CLOSURE_INIT(
&on_next_report_timer_, OnNextReportTimerLocked, this,
grpc_combiner_scheduler(xdslb_policy()->combiner()));
GRPC_CLOSURE_INIT(
&on_report_done_, OnReportDoneLocked, this,
grpc_combiner_scheduler(xdslb_policy()->combiner()));
ScheduleNextReportLocked();
}
void Orphan() override;
private:
void ScheduleNextReportLocked();
static void OnNextReportTimerLocked(void* arg, grpc_error* error);
void SendReportLocked();
static void OnReportDoneLocked(void* arg, grpc_error* error);
bool IsCurrentReporterOnCall() const {
return this == parent_->reporter_.get();
}
XdsLb* xdslb_policy() const { return parent_->xdslb_policy(); }
// The owning LRS call.
RefCountedPtr<LrsCallState> parent_;
// The load reporting state.
const grpc_millis report_interval_;
bool last_report_counters_were_zero_ = false;
bool next_report_timer_callback_pending_ = false;
grpc_timer next_report_timer_;
grpc_closure on_next_report_timer_;
grpc_closure on_report_done_;
};
static void OnInitialRequestSentLocked(void* arg, grpc_error* error);
static void OnResponseReceivedLocked(void* arg, grpc_error* error);
static void OnStatusReceivedLocked(void* arg, grpc_error* error);
bool IsCurrentCallOnChannel() const;
// The owning RetryableLbCall<>.
RefCountedPtr<RetryableLbCall<LrsCallState>> parent_;
bool seen_response_ = false;
// Always non-NULL.
grpc_call* lb_call_;
// recv_initial_metadata
grpc_metadata_array initial_metadata_recv_;
// send_message
grpc_byte_buffer* send_message_payload_ = nullptr;
grpc_closure on_initial_request_sent_;
// recv_message
grpc_byte_buffer* recv_message_payload_ = nullptr;
grpc_closure on_response_received_;
// recv_trailing_metadata
grpc_metadata_array trailing_metadata_recv_;
grpc_status_code status_code_;
grpc_slice status_details_;
grpc_closure on_status_received_;
// Load reporting state.
UniquePtr<char> cluster_name_;
grpc_millis load_reporting_interval_ = 0;
OrphanablePtr<Reporter> reporter_;
};
LbChannelState(RefCountedPtr<XdsLb> xdslb_policy, const char* balancer_name,
const grpc_channel_args& args);
~LbChannelState();
void Orphan() override;
grpc_channel* channel() const { return channel_; }
XdsLb* xdslb_policy() const { return xdslb_policy_.get(); }
EdsCallState* eds_calld() const { return eds_calld_->lb_calld(); }
LrsCallState* lrs_calld() const { return lrs_calld_->lb_calld(); }
bool IsCurrentChannel() const {
return this == xdslb_policy_->lb_chand_.get();
}
bool IsPendingChannel() const {
return this == xdslb_policy_->pending_lb_chand_.get();
}
bool HasActiveEdsCall() const { return eds_calld_->lb_calld() != nullptr; }
void StartConnectivityWatchLocked();
void CancelConnectivityWatchLocked();
static void OnConnectivityChangedLocked(void* arg, grpc_error* error);
private:
// The owning LB policy.
RefCountedPtr<XdsLb> xdslb_policy_;
// The channel and its status.
grpc_channel* channel_;
bool shutting_down_ = false;
grpc_connectivity_state connectivity_ = GRPC_CHANNEL_IDLE;
grpc_closure on_connectivity_changed_;
// The retryable XDS calls to the LB server.
OrphanablePtr<RetryableLbCall<EdsCallState>> eds_calld_;
OrphanablePtr<RetryableLbCall<LrsCallState>> lrs_calld_;
};
// We need this wrapper for the following reasons:
// 1. To process per-locality load reporting.
// 2. Since pickers are UniquePtrs we use this RefCounted wrapper to control
// references to it by the xds picker and the locality.
class PickerWrapper : public RefCounted<PickerWrapper> {
public:
PickerWrapper(UniquePtr<SubchannelPicker> picker,
RefCountedPtr<XdsClientStats::LocalityStats> locality_stats)
: picker_(std::move(picker)),
locality_stats_(std::move(locality_stats)) {
locality_stats_->RefByPicker();
}
~PickerWrapper() { locality_stats_->UnrefByPicker(); }
PickResult Pick(PickArgs args);
private:
static void RecordCallCompletion(
void* arg, grpc_error* error,
LoadBalancingPolicy::MetadataInterface* recv_trailing_metadata,
LoadBalancingPolicy::CallState* call_state);
UniquePtr<SubchannelPicker> picker_;
RefCountedPtr<XdsClientStats::LocalityStats> locality_stats_;
};
// The picker will use a stateless weighting algorithm to pick the locality to
// use for each request.
class Picker : public SubchannelPicker {
public:
// Maintains a weighted list of pickers from each locality that is in ready
// state. The first element in the pair represents the end of a range
// proportional to the locality's weight. The start of the range is the
// previous value in the vector and is 0 for the first element.
using PickerList =
InlinedVector<Pair<uint32_t, RefCountedPtr<PickerWrapper>>, 1>;
Picker(RefCountedPtr<XdsLb> xds_policy, PickerList pickers)
: xds_policy_(std::move(xds_policy)),
pickers_(std::move(pickers)),
drop_config_(xds_policy_->drop_config_) {}
PickResult Pick(PickArgs args) override;
private:
// Calls the picker of the locality that the key falls within.
PickResult PickFromLocality(const uint32_t key, PickArgs args);
RefCountedPtr<XdsLb> xds_policy_;
PickerList pickers_;
RefCountedPtr<XdsDropConfig> drop_config_;
};
class FallbackHelper : public ChannelControlHelper {
public:
explicit FallbackHelper(RefCountedPtr<XdsLb> parent)
: parent_(std::move(parent)) {}
~FallbackHelper() { parent_.reset(DEBUG_LOCATION, "FallbackHelper"); }
RefCountedPtr<SubchannelInterface> CreateSubchannel(
const grpc_channel_args& args) override;
void UpdateState(grpc_connectivity_state state,
UniquePtr<SubchannelPicker> picker) override;
void RequestReresolution() override;
void AddTraceEvent(TraceSeverity severity, StringView message) override;
void set_child(LoadBalancingPolicy* child) { child_ = child; }
private:
bool CalledByPendingFallback() const;
bool CalledByCurrentFallback() const;
RefCountedPtr<XdsLb> parent_;
LoadBalancingPolicy* child_ = nullptr;
};
// There is only one PriorityList instance, which has the same lifetime with
// the XdsLb instance.
class PriorityList {
public:
// Each LocalityMap holds a ref to the XdsLb.
class LocalityMap : public InternallyRefCounted<LocalityMap> {
public:
// Each Locality holds a ref to the LocalityMap it is in.
class Locality : public InternallyRefCounted<Locality> {
public:
Locality(RefCountedPtr<LocalityMap> locality_map,
RefCountedPtr<XdsLocalityName> name);
~Locality();
void UpdateLocked(uint32_t locality_weight,
ServerAddressList serverlist);
void ShutdownLocked();
void ResetBackoffLocked();
void DeactivateLocked();
void Orphan() override;
grpc_connectivity_state connectivity_state() const {
return connectivity_state_;
}
uint32_t weight() const { return weight_; }
RefCountedPtr<PickerWrapper> picker_wrapper() const {
return picker_wrapper_;
}
void set_locality_map(RefCountedPtr<LocalityMap> locality_map) {
locality_map_ = std::move(locality_map);
}
private:
class Helper : public ChannelControlHelper {
public:
explicit Helper(RefCountedPtr<Locality> locality)
: locality_(std::move(locality)) {}
~Helper() { locality_.reset(DEBUG_LOCATION, "Helper"); }
RefCountedPtr<SubchannelInterface> CreateSubchannel(
const grpc_channel_args& args) override;
void UpdateState(grpc_connectivity_state state,
UniquePtr<SubchannelPicker> picker) override;
void RequestReresolution() override;
void AddTraceEvent(TraceSeverity severity,
StringView message) override;
void set_child(LoadBalancingPolicy* child) { child_ = child; }
private:
bool CalledByPendingChild() const;
bool CalledByCurrentChild() const;
RefCountedPtr<Locality> locality_;
LoadBalancingPolicy* child_ = nullptr;
};
// Methods for dealing with the child policy.
OrphanablePtr<LoadBalancingPolicy> CreateChildPolicyLocked(
const char* name, const grpc_channel_args* args);
grpc_channel_args* CreateChildPolicyArgsLocked(
const grpc_channel_args* args);
static void OnDelayedRemovalTimerLocked(void* arg, grpc_error* error);
XdsLb* xds_policy() const { return locality_map_->xds_policy(); }
// The owning locality map.
RefCountedPtr<LocalityMap> locality_map_;
RefCountedPtr<XdsLocalityName> name_;
OrphanablePtr<LoadBalancingPolicy> child_policy_;
OrphanablePtr<LoadBalancingPolicy> pending_child_policy_;
RefCountedPtr<PickerWrapper> picker_wrapper_;
grpc_connectivity_state connectivity_state_ = GRPC_CHANNEL_IDLE;
uint32_t weight_;
// States for delayed removal.
grpc_timer delayed_removal_timer_;
grpc_closure on_delayed_removal_timer_;
bool delayed_removal_timer_callback_pending_ = false;
bool shutdown_ = false;
};
LocalityMap(RefCountedPtr<XdsLb> xds_policy, uint32_t priority);
void UpdateLocked(
const XdsPriorityListUpdate::LocalityMap& locality_map_update);
void ResetBackoffLocked();
void UpdateXdsPickerLocked();
OrphanablePtr<Locality> ExtractLocalityLocked(
const RefCountedPtr<XdsLocalityName>& name);
void DeactivateLocked();
// Returns true if this locality map becomes the currently used one (i.e.,
// its priority is selected) after reactivation.
bool MaybeReactivateLocked();
void MaybeCancelFailoverTimerLocked();
void Orphan() override;
XdsLb* xds_policy() const { return xds_policy_.get(); }
uint32_t priority() const { return priority_; }
grpc_connectivity_state connectivity_state() const {
return connectivity_state_;
}
bool failover_timer_callback_pending() const {
return failover_timer_callback_pending_;
}
private:
void OnLocalityStateUpdateLocked();
void UpdateConnectivityStateLocked();
static void OnDelayedRemovalTimerLocked(void* arg, grpc_error* error);
static void OnFailoverTimerLocked(void* arg, grpc_error* error);
PriorityList* priority_list() const {
return &xds_policy_->priority_list_;
}
const XdsPriorityListUpdate& priority_list_update() const {
return xds_policy_->priority_list_update_;
}
const XdsPriorityListUpdate::LocalityMap* locality_map_update() const {
return xds_policy_->priority_list_update_.Find(priority_);
}
RefCountedPtr<XdsLb> xds_policy_;
Map<RefCountedPtr<XdsLocalityName>, OrphanablePtr<Locality>,
XdsLocalityName::Less>
localities_;
const uint32_t priority_;
grpc_connectivity_state connectivity_state_ = GRPC_CHANNEL_IDLE;
// States for delayed removal.
grpc_timer delayed_removal_timer_;
grpc_closure on_delayed_removal_timer_;
bool delayed_removal_timer_callback_pending_ = false;
// States of failover.
grpc_timer failover_timer_;
grpc_closure on_failover_timer_;
bool failover_timer_callback_pending_ = false;
};
explicit PriorityList(XdsLb* xds_policy) : xds_policy_(xds_policy) {}
void UpdateLocked();
void ResetBackoffLocked();
void ShutdownLocked();
void UpdateXdsPickerLocked();
const XdsPriorityListUpdate& priority_list_update() const {
return xds_policy_->priority_list_update_;
}
uint32_t current_priority() const { return current_priority_; }
private:
void MaybeCreateLocalityMapLocked(uint32_t priority);
void FailoverOnConnectionFailureLocked();
void FailoverOnDisconnectionLocked(uint32_t failed_priority);
void SwitchToHigherPriorityLocked(uint32_t priority);
void DeactivatePrioritiesLowerThan(uint32_t priority);
OrphanablePtr<LocalityMap::Locality> ExtractLocalityLocked(
const RefCountedPtr<XdsLocalityName>& name, uint32_t exclude_priority);
// Callers should make sure the priority list is non-empty.
uint32_t LowestPriority() const {
return static_cast<uint32_t>(priorities_.size()) - 1;
}
bool Contains(uint32_t priority) { return priority < priorities_.size(); }
XdsLb* xds_policy_;
// The list of locality maps, indexed by priority. P0 is the highest
// priority.
InlinedVector<OrphanablePtr<LocalityMap>, 2> priorities_;
// The priority that is being used.
uint32_t current_priority_ = UINT32_MAX;
};
~XdsLb();
void ShutdownLocked() override;
// Helper function used in UpdateLocked().
void ProcessAddressesAndChannelArgsLocked(ServerAddressList addresses,
const grpc_channel_args& args);
// Parses the xds config given the JSON node of the first child of XdsConfig.
// If parsing succeeds, updates \a balancer_name, and updates \a
// child_policy_config_ and \a fallback_policy_config_ if they are also
// found. Does nothing upon failure.
void ParseLbConfig(const ParsedXdsConfig* xds_config);
LbChannelState* LatestLbChannel() const {
return pending_lb_chand_ != nullptr ? pending_lb_chand_.get()
: lb_chand_.get();
}
// Methods for dealing with fallback state.
void MaybeCancelFallbackAtStartupChecks();
static void OnFallbackTimerLocked(void* arg, grpc_error* error);
void UpdateFallbackPolicyLocked();
OrphanablePtr<LoadBalancingPolicy> CreateFallbackPolicyLocked(
const char* name, const grpc_channel_args* args);
void MaybeExitFallbackMode();
// Name of the backend server to connect to.
const char* server_name_ = nullptr;
// Name of the balancer to connect to.
UniquePtr<char> balancer_name_;
// Current channel args from the resolver.
grpc_channel_args* args_ = nullptr;
// Internal state.
bool shutting_down_ = false;
// The channel for communicating with the LB server.
OrphanablePtr<LbChannelState> lb_chand_;
OrphanablePtr<LbChannelState> pending_lb_chand_;
// Timeout in milliseconds for the LB call. 0 means no deadline.
const grpc_millis lb_call_timeout_ms_;
// Whether the checks for fallback at startup are ALL pending. There are
// several cases where this can be reset:
// 1. The fallback timer fires, we enter fallback mode.
// 2. Before the fallback timer fires, the LB channel becomes
// TRANSIENT_FAILURE or the LB call fails, we enter fallback mode.
// 3. Before the fallback timer fires, if any child policy in the locality map
// becomes READY, we cancel the fallback timer.
bool fallback_at_startup_checks_pending_ = false;
// Timeout in milliseconds for before using fallback backend addresses.
// 0 means not using fallback.
const grpc_millis lb_fallback_timeout_ms_;
// The backend addresses from the resolver.
ServerAddressList fallback_backend_addresses_;
// Fallback timer.
grpc_timer lb_fallback_timer_;
grpc_closure lb_on_fallback_;
// The policy to use for the fallback backends.
RefCountedPtr<LoadBalancingPolicy::Config> fallback_policy_config_;
// Non-null iff we are in fallback mode.
OrphanablePtr<LoadBalancingPolicy> fallback_policy_;
OrphanablePtr<LoadBalancingPolicy> pending_fallback_policy_;
// The policy to use for the backends.
RefCountedPtr<LoadBalancingPolicy::Config> child_policy_config_;
const grpc_millis locality_retention_interval_ms_;
const grpc_millis locality_map_failover_timeout_ms_;
// A list of locality maps indexed by priority.
PriorityList priority_list_;
// The update for priority_list_.
XdsPriorityListUpdate priority_list_update_;
// The config for dropping calls.
RefCountedPtr<XdsDropConfig> drop_config_;
// The stats for client-side load reporting.
XdsClientStats client_stats_;
};
//
// XdsLb::PickerWrapper::Pick
//
LoadBalancingPolicy::PickResult XdsLb::PickerWrapper::Pick(
LoadBalancingPolicy::PickArgs args) {
// Forward the pick to the picker returned from the child policy.
PickResult result = picker_->Pick(args);
if (result.type != PickResult::PICK_COMPLETE ||
result.subchannel == nullptr || locality_stats_ == nullptr) {
return result;
}
// Record a call started.
locality_stats_->AddCallStarted();
// Intercept the recv_trailing_metadata op to record call completion.
result.recv_trailing_metadata_ready = RecordCallCompletion;
result.recv_trailing_metadata_ready_user_data =
locality_stats_->Ref(DEBUG_LOCATION, "LocalityStats+call").release();
return result;
}
// Note that the following callback does not run in either the control plane
// combiner or the data plane combiner.
void XdsLb::PickerWrapper::RecordCallCompletion(
void* arg, grpc_error* error,
LoadBalancingPolicy::MetadataInterface* recv_trailing_metadata,
LoadBalancingPolicy::CallState* call_state) {
XdsClientStats::LocalityStats* locality_stats =
static_cast<XdsClientStats::LocalityStats*>(arg);
const bool call_failed = error != GRPC_ERROR_NONE;
locality_stats->AddCallFinished(call_failed);
locality_stats->Unref(DEBUG_LOCATION, "LocalityStats+call");
}
//
// XdsLb::Picker
//
XdsLb::PickResult XdsLb::Picker::Pick(PickArgs args) {
// Handle drop.
const UniquePtr<char>* drop_category;
if (drop_config_->ShouldDrop(&drop_category)) {
xds_policy_->client_stats_.AddCallDropped(*drop_category);
PickResult result;
result.type = PickResult::PICK_COMPLETE;
return result;
}
// Generate a random number in [0, total weight).
const uint32_t key = rand() % pickers_[pickers_.size() - 1].first;
// Forward pick to whichever locality maps to the range in which the
// random number falls in.
return PickFromLocality(key, args);
}
XdsLb::PickResult XdsLb::Picker::PickFromLocality(const uint32_t key,
PickArgs args) {
size_t mid = 0;
size_t start_index = 0;
size_t end_index = pickers_.size() - 1;
size_t index = 0;
while (end_index > start_index) {
mid = (start_index + end_index) / 2;
if (pickers_[mid].first > key) {
end_index = mid;
} else if (pickers_[mid].first < key) {
start_index = mid + 1;
} else {
index = mid + 1;
break;
}
}
if (index == 0) index = start_index;
GPR_ASSERT(pickers_[index].first > key);
return pickers_[index].second->Pick(args);
}
//
// XdsLb::FallbackHelper
//
bool XdsLb::FallbackHelper::CalledByPendingFallback() const {
GPR_ASSERT(child_ != nullptr);
return child_ == parent_->pending_fallback_policy_.get();
}
bool XdsLb::FallbackHelper::CalledByCurrentFallback() const {
GPR_ASSERT(child_ != nullptr);
return child_ == parent_->fallback_policy_.get();
}
RefCountedPtr<SubchannelInterface> XdsLb::FallbackHelper::CreateSubchannel(
const grpc_channel_args& args) {
if (parent_->shutting_down_ ||
(!CalledByPendingFallback() && !CalledByCurrentFallback())) {
return nullptr;
}
return parent_->channel_control_helper()->CreateSubchannel(args);
}
void XdsLb::FallbackHelper::UpdateState(grpc_connectivity_state state,
UniquePtr<SubchannelPicker> picker) {
if (parent_->shutting_down_) return;
// If this request is from the pending fallback policy, ignore it until
// it reports READY, at which point we swap it into place.
if (CalledByPendingFallback()) {
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(
GPR_INFO,
"[xdslb %p helper %p] pending fallback policy %p reports state=%s",
parent_.get(), this, parent_->pending_fallback_policy_.get(),
grpc_connectivity_state_name(state));
}
if (state != GRPC_CHANNEL_READY) return;
grpc_pollset_set_del_pollset_set(
parent_->fallback_policy_->interested_parties(),
parent_->interested_parties());
parent_->fallback_policy_ = std::move(parent_->pending_fallback_policy_);
} else if (!CalledByCurrentFallback()) {
// This request is from an outdated fallback policy, so ignore it.
return;
}
parent_->channel_control_helper()->UpdateState(state, std::move(picker));
}
void XdsLb::FallbackHelper::RequestReresolution() {
if (parent_->shutting_down_) return;
const LoadBalancingPolicy* latest_fallback_policy =
parent_->pending_fallback_policy_ != nullptr
? parent_->pending_fallback_policy_.get()
: parent_->fallback_policy_.get();
if (child_ != latest_fallback_policy) return;
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO,
"[xdslb %p] Re-resolution requested from the fallback policy (%p).",
parent_.get(), child_);
}
GPR_ASSERT(parent_->lb_chand_ != nullptr);
parent_->channel_control_helper()->RequestReresolution();
}
void XdsLb::FallbackHelper::AddTraceEvent(TraceSeverity severity,
StringView message) {
if (parent_->shutting_down_ ||
(!CalledByPendingFallback() && !CalledByCurrentFallback())) {
return;
}
parent_->channel_control_helper()->AddTraceEvent(severity, message);
}
//
// XdsLb::LbChannelState
//
XdsLb::LbChannelState::LbChannelState(RefCountedPtr<XdsLb> xdslb_policy,
const char* balancer_name,
const grpc_channel_args& args)
: InternallyRefCounted<LbChannelState>(&grpc_lb_xds_trace),
xdslb_policy_(std::move(xdslb_policy)) {
GRPC_CLOSURE_INIT(&on_connectivity_changed_, OnConnectivityChangedLocked,
this, grpc_combiner_scheduler(xdslb_policy_->combiner()));
channel_ = CreateXdsBalancerChannel(balancer_name, args);
GPR_ASSERT(channel_ != nullptr);
eds_calld_.reset(New<RetryableLbCall<EdsCallState>>(
Ref(DEBUG_LOCATION, "LbChannelState+eds")));
lrs_calld_.reset(New<RetryableLbCall<LrsCallState>>(
Ref(DEBUG_LOCATION, "LbChannelState+lrs")));
}
XdsLb::LbChannelState::~LbChannelState() {
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO, "[xdslb %p] Destroying LB channel %p", xdslb_policy(),
this);
}
grpc_channel_destroy(channel_);
}
void XdsLb::LbChannelState::Orphan() {
shutting_down_ = true;
eds_calld_.reset();
lrs_calld_.reset();
Unref(DEBUG_LOCATION, "LbChannelState+orphaned");
}
void XdsLb::LbChannelState::StartConnectivityWatchLocked() {
grpc_channel_element* client_channel_elem =
grpc_channel_stack_last_element(grpc_channel_get_channel_stack(channel_));
GPR_ASSERT(client_channel_elem->filter == &grpc_client_channel_filter);
// Ref held by callback.
Ref(DEBUG_LOCATION, "LbChannelState+start_watch").release();
grpc_client_channel_watch_connectivity_state(
client_channel_elem,
grpc_polling_entity_create_from_pollset_set(
xdslb_policy_->interested_parties()),
&connectivity_, &on_connectivity_changed_, nullptr);
}
void XdsLb::LbChannelState::CancelConnectivityWatchLocked() {
grpc_channel_element* client_channel_elem =
grpc_channel_stack_last_element(grpc_channel_get_channel_stack(channel_));
GPR_ASSERT(client_channel_elem->filter == &grpc_client_channel_filter);
grpc_client_channel_watch_connectivity_state(
client_channel_elem,
grpc_polling_entity_create_from_pollset_set(
xdslb_policy_->interested_parties()),
nullptr, &on_connectivity_changed_, nullptr);
}
void XdsLb::LbChannelState::OnConnectivityChangedLocked(void* arg,
grpc_error* error) {
LbChannelState* self = static_cast<LbChannelState*>(arg);
if (!self->shutting_down_ &&
self->xdslb_policy_->fallback_at_startup_checks_pending_) {
if (self->connectivity_ != GRPC_CHANNEL_TRANSIENT_FAILURE) {
// Not in TRANSIENT_FAILURE. Renew connectivity watch.
grpc_channel_element* client_channel_elem =
grpc_channel_stack_last_element(
grpc_channel_get_channel_stack(self->channel_));
GPR_ASSERT(client_channel_elem->filter == &grpc_client_channel_filter);
grpc_client_channel_watch_connectivity_state(
client_channel_elem,
grpc_polling_entity_create_from_pollset_set(
self->xdslb_policy_->interested_parties()),
&self->connectivity_, &self->on_connectivity_changed_, nullptr);
return; // Early out so we don't drop the ref below.
}
// In TRANSIENT_FAILURE. Cancel the fallback timer and go into
// fallback mode immediately.
gpr_log(GPR_INFO,
"[xdslb %p] Balancer channel in state TRANSIENT_FAILURE; "
"entering fallback mode",
self);
self->xdslb_policy_->fallback_at_startup_checks_pending_ = false;
grpc_timer_cancel(&self->xdslb_policy_->lb_fallback_timer_);
self->xdslb_policy_->UpdateFallbackPolicyLocked();
}
// Done watching connectivity state, so drop ref.
self->Unref(DEBUG_LOCATION, "LbChannelState+watch_done");
}
//
// XdsLb::LbChannelState::RetryableLbCall<>
//
template <typename T>
XdsLb::LbChannelState::RetryableLbCall<T>::RetryableLbCall(
RefCountedPtr<LbChannelState> lb_chand)
: lb_chand_(std::move(lb_chand)),
backoff_(
BackOff::Options()
.set_initial_backoff(GRPC_XDS_INITIAL_CONNECT_BACKOFF_SECONDS *
1000)
.set_multiplier(GRPC_XDS_RECONNECT_BACKOFF_MULTIPLIER)
.set_jitter(GRPC_XDS_RECONNECT_JITTER)
.set_max_backoff(GRPC_XDS_RECONNECT_MAX_BACKOFF_SECONDS * 1000)) {
GRPC_CLOSURE_INIT(
&on_retry_timer_, OnRetryTimerLocked, this,
grpc_combiner_scheduler(lb_chand_->xdslb_policy()->combiner()));
StartNewCallLocked();
}
template <typename T>
void XdsLb::LbChannelState::RetryableLbCall<T>::Orphan() {
shutting_down_ = true;
lb_calld_.reset();
if (retry_timer_callback_pending_) grpc_timer_cancel(&retry_timer_);
this->Unref(DEBUG_LOCATION, "RetryableLbCall+orphaned");
}
template <typename T>
void XdsLb::LbChannelState::RetryableLbCall<T>::OnCallFinishedLocked() {
const bool seen_response = lb_calld_->seen_response();
lb_calld_.reset();
if (seen_response) {
// If we lost connection to the LB server, reset backoff and restart the LB
// call immediately.
backoff_.Reset();
StartNewCallLocked();
} else {
// If we failed to connect to the LB server, retry later.
StartRetryTimerLocked();
}
}
template <typename T>
void XdsLb::LbChannelState::RetryableLbCall<T>::StartNewCallLocked() {
if (shutting_down_) return;
GPR_ASSERT(lb_chand_->channel_ != nullptr);
GPR_ASSERT(lb_calld_ == nullptr);
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO,
"[xdslb %p] Start new call from retryable call (lb_chand: %p, "
"retryable call: %p)",
lb_chand()->xdslb_policy(), lb_chand(), this);
}
lb_calld_ = MakeOrphanable<T>(
this->Ref(DEBUG_LOCATION, "RetryableLbCall+start_new_call"));
}
template <typename T>
void XdsLb::LbChannelState::RetryableLbCall<T>::StartRetryTimerLocked() {
if (shutting_down_) return;
const grpc_millis next_attempt_time = backoff_.NextAttemptTime();
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
grpc_millis timeout = GPR_MAX(next_attempt_time - ExecCtx::Get()->Now(), 0);
gpr_log(GPR_INFO,
"[xdslb %p] Failed to connect to LB server (lb_chand: %p) "
"retry timer will fire in %" PRId64 "ms.",
lb_chand()->xdslb_policy(), lb_chand(), timeout);
}
this->Ref(DEBUG_LOCATION, "RetryableLbCall+retry_timer_start").release();
grpc_timer_init(&retry_timer_, next_attempt_time, &on_retry_timer_);
retry_timer_callback_pending_ = true;
}
template <typename T>
void XdsLb::LbChannelState::RetryableLbCall<T>::OnRetryTimerLocked(
void* arg, grpc_error* error) {
RetryableLbCall* lb_calld = static_cast<RetryableLbCall*>(arg);
lb_calld->retry_timer_callback_pending_ = false;
if (!lb_calld->shutting_down_ && error == GRPC_ERROR_NONE) {
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO,
"[xdslb %p] Retry timer fires (lb_chand: %p, retryable call: %p)",
lb_calld->lb_chand()->xdslb_policy(), lb_calld->lb_chand(),
lb_calld);
}
lb_calld->StartNewCallLocked();
}
lb_calld->Unref(DEBUG_LOCATION, "RetryableLbCall+retry_timer_done");
}
//
// XdsLb::LbChannelState::EdsCallState
//
XdsLb::LbChannelState::EdsCallState::EdsCallState(
RefCountedPtr<RetryableLbCall<EdsCallState>> parent)
: InternallyRefCounted<EdsCallState>(&grpc_lb_xds_trace),
parent_(std::move(parent)) {
// Init the LB call. Note that the LB call will progress every time there's
// activity in xdslb_policy()->interested_parties(), which is comprised of
// the polling entities from client_channel.
GPR_ASSERT(xdslb_policy() != nullptr);
GPR_ASSERT(xdslb_policy()->server_name_ != nullptr);
GPR_ASSERT(xdslb_policy()->server_name_[0] != '\0');
const grpc_millis deadline =
xdslb_policy()->lb_call_timeout_ms_ == 0
? GRPC_MILLIS_INF_FUTURE
: ExecCtx::Get()->Now() + xdslb_policy()->lb_call_timeout_ms_;
// Create an LB call with the specified method name.
lb_call_ = grpc_channel_create_pollset_set_call(
lb_chand()->channel_, nullptr, GRPC_PROPAGATE_DEFAULTS,
xdslb_policy()->interested_parties(),
GRPC_MDSTR_SLASH_ENVOY_DOT_API_DOT_V2_DOT_ENDPOINTDISCOVERYSERVICE_SLASH_STREAMENDPOINTS,
nullptr, deadline, nullptr);
GPR_ASSERT(lb_call_ != nullptr);
// Init the LB call request payload.
grpc_slice request_payload_slice =
XdsEdsRequestCreateAndEncode(xdslb_policy()->server_name_);
send_message_payload_ =
grpc_raw_byte_buffer_create(&request_payload_slice, 1);
grpc_slice_unref_internal(request_payload_slice);
// Init other data associated with the LB call.
grpc_metadata_array_init(&initial_metadata_recv_);
grpc_metadata_array_init(&trailing_metadata_recv_);
GRPC_CLOSURE_INIT(&on_response_received_, OnResponseReceivedLocked, this,
grpc_combiner_scheduler(xdslb_policy()->combiner()));
GRPC_CLOSURE_INIT(&on_status_received_, OnStatusReceivedLocked, this,
grpc_combiner_scheduler(xdslb_policy()->combiner()));
// Start the call.
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO,
"[xdslb %p] Starting EDS call (lb_chand: %p, lb_calld: %p, "
"lb_call: %p)",
xdslb_policy(), lb_chand(), this, lb_call_);
}
// Create the ops.
grpc_call_error call_error;
grpc_op ops[3];
memset(ops, 0, sizeof(ops));
// Op: send initial metadata.
grpc_op* op = ops;
op->op = GRPC_OP_SEND_INITIAL_METADATA;
op->data.send_initial_metadata.count = 0;
op->flags = 0;
op->reserved = nullptr;
op++;
// Op: send request message.
GPR_ASSERT(send_message_payload_ != nullptr);
op->op = GRPC_OP_SEND_MESSAGE;
op->data.send_message.send_message = send_message_payload_;
op->flags = 0;
op->reserved = nullptr;
op++;
call_error = grpc_call_start_batch_and_execute(lb_call_, ops,
(size_t)(op - ops), nullptr);
GPR_ASSERT(GRPC_CALL_OK == call_error);
// Op: recv initial metadata.
op = ops;
op->op = GRPC_OP_RECV_INITIAL_METADATA;
op->data.recv_initial_metadata.recv_initial_metadata =
&initial_metadata_recv_;
op->flags = 0;
op->reserved = nullptr;
op++;
// Op: recv response.
op->op = GRPC_OP_RECV_MESSAGE;
op->data.recv_message.recv_message = &recv_message_payload_;
op->flags = 0;
op->reserved = nullptr;
op++;
Ref(DEBUG_LOCATION, "EDS+OnResponseReceivedLocked").release();
call_error = grpc_call_start_batch_and_execute(
lb_call_, ops, (size_t)(op - ops), &on_response_received_);
GPR_ASSERT(GRPC_CALL_OK == call_error);
// Op: recv server status.
op = ops;
op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv_;
op->data.recv_status_on_client.status = &status_code_;
op->data.recv_status_on_client.status_details = &status_details_;
op->flags = 0;
op->reserved = nullptr;
op++;
// This callback signals the end of the LB call, so it relies on the initial
// ref instead of a new ref. When it's invoked, it's the initial ref that is
// unreffed.
call_error = grpc_call_start_batch_and_execute(
lb_call_, ops, (size_t)(op - ops), &on_status_received_);
GPR_ASSERT(GRPC_CALL_OK == call_error);
}
XdsLb::LbChannelState::EdsCallState::~EdsCallState() {
grpc_metadata_array_destroy(&initial_metadata_recv_);
grpc_metadata_array_destroy(&trailing_metadata_recv_);
grpc_byte_buffer_destroy(send_message_payload_);
grpc_byte_buffer_destroy(recv_message_payload_);
grpc_slice_unref_internal(status_details_);
GPR_ASSERT(lb_call_ != nullptr);
grpc_call_unref(lb_call_);
}
void XdsLb::LbChannelState::EdsCallState::Orphan() {
GPR_ASSERT(lb_call_ != nullptr);
// If we are here because xdslb_policy wants to cancel the call,
// on_status_received_ will complete the cancellation and clean up. Otherwise,
// we are here because xdslb_policy has to orphan a failed call, then the
// following cancellation will be a no-op.
grpc_call_cancel(lb_call_, nullptr);
// Note that the initial ref is hold by on_status_received_. So the
// corresponding unref happens in on_status_received_ instead of here.
}
void XdsLb::LbChannelState::EdsCallState::OnResponseReceivedLocked(
void* arg, grpc_error* error) {
EdsCallState* eds_calld = static_cast<EdsCallState*>(arg);
LbChannelState* lb_chand = eds_calld->lb_chand();
XdsLb* xdslb_policy = eds_calld->xdslb_policy();
// Empty payload means the LB call was cancelled.
if (!eds_calld->IsCurrentCallOnChannel() ||
eds_calld->recv_message_payload_ == nullptr) {
eds_calld->Unref(DEBUG_LOCATION, "EDS+OnResponseReceivedLocked");
return;
}
// Read the response.
grpc_byte_buffer_reader bbr;
grpc_byte_buffer_reader_init(&bbr, eds_calld->recv_message_payload_);
grpc_slice response_slice = grpc_byte_buffer_reader_readall(&bbr);
grpc_byte_buffer_reader_destroy(&bbr);
grpc_byte_buffer_destroy(eds_calld->recv_message_payload_);
eds_calld->recv_message_payload_ = nullptr;
// TODO(juanlishen): When we convert this to use the xds protocol, the
// balancer will send us a fallback timeout such that we should go into
// fallback mode if we have lost contact with the balancer after a certain
// period of time. We will need to save the timeout value here, and then
// when the balancer call ends, we will need to start a timer for the
// specified period of time, and if the timer fires, we go into fallback
// mode. We will also need to cancel the timer when we receive a serverlist
// from the balancer.
// This anonymous lambda is a hack to avoid the usage of goto.
[&]() {
// Parse the response.
XdsUpdate update;
grpc_error* parse_error =
XdsEdsResponseDecodeAndParse(response_slice, &update);
if (parse_error != GRPC_ERROR_NONE) {
gpr_log(GPR_ERROR, "[xdslb %p] EDS response parsing failed. error=%s",
xdslb_policy, grpc_error_string(parse_error));
GRPC_ERROR_UNREF(parse_error);
return;
}
if (update.priority_list_update.empty() && !update.drop_all) {
char* response_slice_str =
grpc_dump_slice(response_slice, GPR_DUMP_ASCII | GPR_DUMP_HEX);
gpr_log(GPR_ERROR,
"[xdslb %p] EDS response '%s' doesn't contain any valid locality "
"but doesn't require to drop all calls. Ignoring.",
xdslb_policy, response_slice_str);
gpr_free(response_slice_str);
return;
}
eds_calld->seen_response_ = true;
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO,
"[xdslb %p] EDS response with %" PRIuPTR
" priorities and %" PRIuPTR
" drop categories received (drop_all=%d)",
xdslb_policy, update.priority_list_update.size(),
update.drop_config->drop_category_list().size(), update.drop_all);
for (size_t priority = 0; priority < update.priority_list_update.size();
++priority) {
const auto* locality_map_update =
update.priority_list_update.Find(static_cast<uint32_t>(priority));
gpr_log(GPR_INFO,
"[xdslb %p] Priority %" PRIuPTR " contains %" PRIuPTR
" localities",
xdslb_policy, priority, locality_map_update->size());
size_t locality_count = 0;
for (const auto& p : locality_map_update->localities) {
const auto& locality = p.second;
gpr_log(GPR_INFO,
"[xdslb %p] Priority %" PRIuPTR ", locality %" PRIuPTR
" %s contains %" PRIuPTR " server addresses",
xdslb_policy, priority, locality_count,
locality.name->AsHumanReadableString(),
locality.serverlist.size());
for (size_t i = 0; i < locality.serverlist.size(); ++i) {
char* ipport;
grpc_sockaddr_to_string(&ipport, &locality.serverlist[i].address(),
false);
gpr_log(GPR_INFO,
"[xdslb %p] Priority %" PRIuPTR ", locality %" PRIuPTR
" %s, server address %" PRIuPTR ": %s",
xdslb_policy, priority, locality_count,
locality.name->AsHumanReadableString(), i, ipport);
gpr_free(ipport);
}
++locality_count;
}
for (size_t i = 0; i < update.drop_config->drop_category_list().size();
++i) {
const XdsDropConfig::DropCategory& drop_category =
update.drop_config->drop_category_list()[i];
gpr_log(GPR_INFO,
"[xdslb %p] Drop category %s has drop rate %d per million",
xdslb_policy, drop_category.name.get(),
drop_category.parts_per_million);
}
}
}
// Pending LB channel receives a response; promote it.
// Note that this call can't be on a discarded pending channel, because
// such channels don't have any current call but we have checked this call
// is a current call.
if (!lb_chand->IsCurrentChannel()) {
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO,
"[xdslb %p] Pending LB channel %p receives EDS response; "
"promoting it to replace current LB channel %p",
xdslb_policy, lb_chand, xdslb_policy->lb_chand_.get());
}
// TODO(juanlishen): Maybe promote the pending LB channel when the
// response results a READY locality map.
xdslb_policy->lb_chand_ = std::move(xdslb_policy->pending_lb_chand_);
}
// At this point, lb_chand must be the current LB channel, so try to start
// load reporting.
LrsCallState* lrs_calld = lb_chand->lrs_calld_->lb_calld();
if (lrs_calld != nullptr) lrs_calld->MaybeStartReportingLocked();
// If the balancer tells us to drop all the calls, we should exit fallback
// mode immediately.
if (update.drop_all) xdslb_policy->MaybeExitFallbackMode();
// Update the drop config.
const bool drop_config_changed =
xdslb_policy->drop_config_ == nullptr ||
*xdslb_policy->drop_config_ != *update.drop_config;
xdslb_policy->drop_config_ = std::move(update.drop_config);
// Ignore identical locality update.
if (xdslb_policy->priority_list_update_ == update.priority_list_update) {
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO,
"[xdslb %p] Incoming locality update identical to current, "
"ignoring. (drop_config_changed=%d)",
xdslb_policy, drop_config_changed);
}
if (drop_config_changed) {
xdslb_policy->priority_list_.UpdateXdsPickerLocked();
}
return;
}
// Update the priority list.
xdslb_policy->priority_list_update_ =
std::move(update.priority_list_update);
xdslb_policy->priority_list_.UpdateLocked();
}();
grpc_slice_unref_internal(response_slice);
if (xdslb_policy->shutting_down_) {
eds_calld->Unref(DEBUG_LOCATION,
"EDS+OnResponseReceivedLocked+xds_shutdown");
return;
}
// Keep listening for serverlist updates.
grpc_op op;
memset(&op, 0, sizeof(op));
op.op = GRPC_OP_RECV_MESSAGE;
op.data.recv_message.recv_message = &eds_calld->recv_message_payload_;
op.flags = 0;
op.reserved = nullptr;
GPR_ASSERT(eds_calld->lb_call_ != nullptr);
// Reuse the "EDS+OnResponseReceivedLocked" ref taken in ctor.
const grpc_call_error call_error = grpc_call_start_batch_and_execute(
eds_calld->lb_call_, &op, 1, &eds_calld->on_response_received_);
GPR_ASSERT(GRPC_CALL_OK == call_error);
}
void XdsLb::LbChannelState::EdsCallState::OnStatusReceivedLocked(
void* arg, grpc_error* error) {
EdsCallState* eds_calld = static_cast<EdsCallState*>(arg);
LbChannelState* lb_chand = eds_calld->lb_chand();
XdsLb* xdslb_policy = eds_calld->xdslb_policy();
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
char* status_details = grpc_slice_to_c_string(eds_calld->status_details_);
gpr_log(GPR_INFO,
"[xdslb %p] EDS call status received. Status = %d, details "
"= '%s', (lb_chand: %p, eds_calld: %p, lb_call: %p), error '%s'",
xdslb_policy, eds_calld->status_code_, status_details, lb_chand,
eds_calld, eds_calld->lb_call_, grpc_error_string(error));
gpr_free(status_details);
}
// Ignore status from a stale call.
if (eds_calld->IsCurrentCallOnChannel()) {
// Because this call is the current one on the channel, the channel can't
// have been swapped out; otherwise, the call should have been reset.
GPR_ASSERT(lb_chand->IsCurrentChannel() || lb_chand->IsPendingChannel());
if (lb_chand != xdslb_policy->LatestLbChannel()) {
// This channel must be the current one and there is a pending one. Swap
// in the pending one and we are done.
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO,
"[xdslb %p] Promoting pending LB channel %p to replace "
"current LB channel %p",
xdslb_policy, lb_chand, xdslb_policy->lb_chand_.get());
}
xdslb_policy->lb_chand_ = std::move(xdslb_policy->pending_lb_chand_);
} else {
// This channel is the most recently created one. Try to restart the call
// and reresolve.
eds_calld->parent_->OnCallFinishedLocked();
xdslb_policy->channel_control_helper()->RequestReresolution();
// If the fallback-at-startup checks are pending, go into fallback mode
// immediately. This short-circuits the timeout for the
// fallback-at-startup case.
if (xdslb_policy->fallback_at_startup_checks_pending_) {
gpr_log(GPR_INFO,
"[xdslb %p] Balancer call finished; entering fallback mode",
xdslb_policy);
xdslb_policy->fallback_at_startup_checks_pending_ = false;
grpc_timer_cancel(&xdslb_policy->lb_fallback_timer_);
lb_chand->CancelConnectivityWatchLocked();
xdslb_policy->UpdateFallbackPolicyLocked();
}
}
}
eds_calld->Unref(DEBUG_LOCATION, "EDS+OnStatusReceivedLocked");
}
bool XdsLb::LbChannelState::EdsCallState::IsCurrentCallOnChannel() const {
// If the retryable EDS call is null (which only happens when the LB channel
// is shutting down), all the EDS calls are stale.
if (lb_chand()->eds_calld_ == nullptr) return false;
return this == lb_chand()->eds_calld_->lb_calld();
}
//
// XdsLb::LbChannelState::LrsCallState::Reporter
//
void XdsLb::LbChannelState::LrsCallState::Reporter::Orphan() {
if (next_report_timer_callback_pending_) {
grpc_timer_cancel(&next_report_timer_);
}
}
void XdsLb::LbChannelState::LrsCallState::Reporter::ScheduleNextReportLocked() {
const grpc_millis next_report_time = ExecCtx::Get()->Now() + report_interval_;
grpc_timer_init(&next_report_timer_, next_report_time,
&on_next_report_timer_);
next_report_timer_callback_pending_ = true;
}
void XdsLb::LbChannelState::LrsCallState::Reporter::OnNextReportTimerLocked(
void* arg, grpc_error* error) {
Reporter* self = static_cast<Reporter*>(arg);
self->next_report_timer_callback_pending_ = false;
if (error != GRPC_ERROR_NONE || !self->IsCurrentReporterOnCall()) {
self->Unref(DEBUG_LOCATION, "Reporter+timer");
return;
}
self->SendReportLocked();
}
void XdsLb::LbChannelState::LrsCallState::Reporter::SendReportLocked() {
// Create a request that contains the load report.
grpc_slice request_payload_slice = XdsLrsRequestCreateAndEncode(
parent_->cluster_name_.get(), &xdslb_policy()->client_stats_);
// Skip client load report if the counters were all zero in the last
// report and they are still zero in this one.
const bool old_val = last_report_counters_were_zero_;
last_report_counters_were_zero_ = static_cast<bool>(
grpc_slice_eq(request_payload_slice, grpc_empty_slice()));
if (old_val && last_report_counters_were_zero_) {
ScheduleNextReportLocked();
return;
}
parent_->send_message_payload_ =
grpc_raw_byte_buffer_create(&request_payload_slice, 1);
grpc_slice_unref_internal(request_payload_slice);
// Send the report.
grpc_op op;
memset(&op, 0, sizeof(op));
op.op = GRPC_OP_SEND_MESSAGE;
op.data.send_message.send_message = parent_->send_message_payload_;
grpc_call_error call_error = grpc_call_start_batch_and_execute(
parent_->lb_call_, &op, 1, &on_report_done_);
if (GPR_UNLIKELY(call_error != GRPC_CALL_OK)) {
gpr_log(GPR_ERROR,
"[xdslb %p] lb_calld=%p call_error=%d sending client load report",
xdslb_policy(), this, call_error);
GPR_ASSERT(GRPC_CALL_OK == call_error);
}
}
void XdsLb::LbChannelState::LrsCallState::Reporter::OnReportDoneLocked(
void* arg, grpc_error* error) {
Reporter* self = static_cast<Reporter*>(arg);
grpc_byte_buffer_destroy(self->parent_->send_message_payload_);
self->parent_->send_message_payload_ = nullptr;
if (error != GRPC_ERROR_NONE || !self->IsCurrentReporterOnCall()) {
// If this reporter is no longer the current one on the call, the reason
// might be that it was orphaned for a new one due to config update.
if (!self->IsCurrentReporterOnCall()) {
self->parent_->MaybeStartReportingLocked();
}
self->Unref(DEBUG_LOCATION, "Reporter+report_done");
return;
}
self->ScheduleNextReportLocked();
}
//
// XdsLb::LbChannelState::LrsCallState
//
XdsLb::LbChannelState::LrsCallState::LrsCallState(
RefCountedPtr<RetryableLbCall<LrsCallState>> parent)
: InternallyRefCounted<LrsCallState>(&grpc_lb_xds_trace),
parent_(std::move(parent)) {
// Init the LB call. Note that the LB call will progress every time there's
// activity in xdslb_policy()->interested_parties(), which is comprised of
// the polling entities from client_channel.
GPR_ASSERT(xdslb_policy() != nullptr);
GPR_ASSERT(xdslb_policy()->server_name_ != nullptr);
GPR_ASSERT(xdslb_policy()->server_name_[0] != '\0');
const grpc_millis deadline =
xdslb_policy()->lb_call_timeout_ms_ == 0
? GRPC_MILLIS_INF_FUTURE
: ExecCtx::Get()->Now() + xdslb_policy()->lb_call_timeout_ms_;
lb_call_ = grpc_channel_create_pollset_set_call(
lb_chand()->channel_, nullptr, GRPC_PROPAGATE_DEFAULTS,
xdslb_policy()->interested_parties(),
GRPC_MDSTR_SLASH_ENVOY_DOT_SERVICE_DOT_LOAD_STATS_DOT_V2_DOT_LOADREPORTINGSERVICE_SLASH_STREAMLOADSTATS,
nullptr, deadline, nullptr);
GPR_ASSERT(lb_call_ != nullptr);
// Init the LB call request payload.
grpc_slice request_payload_slice =
XdsLrsRequestCreateAndEncode(xdslb_policy()->server_name_);
send_message_payload_ =
grpc_raw_byte_buffer_create(&request_payload_slice, 1);
grpc_slice_unref_internal(request_payload_slice);
// Init other data associated with the LRS call.
grpc_metadata_array_init(&initial_metadata_recv_);
grpc_metadata_array_init(&trailing_metadata_recv_);
GRPC_CLOSURE_INIT(&on_initial_request_sent_, OnInitialRequestSentLocked, this,
grpc_combiner_scheduler(xdslb_policy()->combiner()));
GRPC_CLOSURE_INIT(&on_response_received_, OnResponseReceivedLocked, this,
grpc_combiner_scheduler(xdslb_policy()->combiner()));
GRPC_CLOSURE_INIT(&on_status_received_, OnStatusReceivedLocked, this,
grpc_combiner_scheduler(xdslb_policy()->combiner()));
// Start the call.
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO,
"[xdslb %p] Starting LRS call (lb_chand: %p, lb_calld: %p, "
"lb_call: %p)",
xdslb_policy(), lb_chand(), this, lb_call_);
}
// Create the ops.
grpc_call_error call_error;
grpc_op ops[3];
memset(ops, 0, sizeof(ops));
// Op: send initial metadata.
grpc_op* op = ops;
op->op = GRPC_OP_SEND_INITIAL_METADATA;
op->data.send_initial_metadata.count = 0;
op->flags = 0;
op->reserved = nullptr;
op++;
// Op: send request message.
GPR_ASSERT(send_message_payload_ != nullptr);
op->op = GRPC_OP_SEND_MESSAGE;
op->data.send_message.send_message = send_message_payload_;
op->flags = 0;
op->reserved = nullptr;
op++;
Ref(DEBUG_LOCATION, "LRS+OnInitialRequestSentLocked").release();
call_error = grpc_call_start_batch_and_execute(
lb_call_, ops, (size_t)(op - ops), &on_initial_request_sent_);
GPR_ASSERT(GRPC_CALL_OK == call_error);
// Op: recv initial metadata.
op = ops;
op->op = GRPC_OP_RECV_INITIAL_METADATA;
op->data.recv_initial_metadata.recv_initial_metadata =
&initial_metadata_recv_;
op->flags = 0;
op->reserved = nullptr;
op++;
// Op: recv response.
op->op = GRPC_OP_RECV_MESSAGE;
op->data.recv_message.recv_message = &recv_message_payload_;
op->flags = 0;
op->reserved = nullptr;
op++;
Ref(DEBUG_LOCATION, "LRS+OnResponseReceivedLocked").release();
call_error = grpc_call_start_batch_and_execute(
lb_call_, ops, (size_t)(op - ops), &on_response_received_);
GPR_ASSERT(GRPC_CALL_OK == call_error);
// Op: recv server status.
op = ops;
op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv_;
op->data.recv_status_on_client.status = &status_code_;
op->data.recv_status_on_client.status_details = &status_details_;
op->flags = 0;
op->reserved = nullptr;
op++;
// This callback signals the end of the LB call, so it relies on the initial
// ref instead of a new ref. When it's invoked, it's the initial ref that is
// unreffed.
call_error = grpc_call_start_batch_and_execute(
lb_call_, ops, (size_t)(op - ops), &on_status_received_);
GPR_ASSERT(GRPC_CALL_OK == call_error);
}
XdsLb::LbChannelState::LrsCallState::~LrsCallState() {
grpc_metadata_array_destroy(&initial_metadata_recv_);
grpc_metadata_array_destroy(&trailing_metadata_recv_);
grpc_byte_buffer_destroy(send_message_payload_);
grpc_byte_buffer_destroy(recv_message_payload_);
grpc_slice_unref_internal(status_details_);
GPR_ASSERT(lb_call_ != nullptr);
grpc_call_unref(lb_call_);
}
void XdsLb::LbChannelState::LrsCallState::Orphan() {
reporter_.reset();
GPR_ASSERT(lb_call_ != nullptr);
// If we are here because xdslb_policy wants to cancel the call,
// on_status_received_ will complete the cancellation and clean up. Otherwise,
// we are here because xdslb_policy has to orphan a failed call, then the
// following cancellation will be a no-op.
grpc_call_cancel(lb_call_, nullptr);
// Note that the initial ref is hold by on_status_received_. So the
// corresponding unref happens in on_status_received_ instead of here.
}
void XdsLb::LbChannelState::LrsCallState::MaybeStartReportingLocked() {
// Don't start if this is not the current call on the current channel.
if (!IsCurrentCallOnChannel() || !lb_chand()->IsCurrentChannel()) return;
// Don't start again if already started.
if (reporter_ != nullptr) return;
// Don't start if the previous send_message op (of the initial request or the
// last report of the previous reporter) hasn't completed.
if (send_message_payload_ != nullptr) return;
// Don't start if no LRS response has arrived.
if (!seen_response()) return;
// Don't start if the EDS call hasn't received any valid response. Note that
// this must be the first channel because it is the current channel but its
// EDS call hasn't seen any response.
EdsCallState* eds_calld = lb_chand()->eds_calld_->lb_calld();
if (eds_calld == nullptr || !eds_calld->seen_response()) return;
// Start reporting.
lb_chand()->xdslb_policy_->client_stats_.MaybeInitLastReportTime();
reporter_ = MakeOrphanable<Reporter>(
Ref(DEBUG_LOCATION, "LRS+load_report+start"), load_reporting_interval_);
}
void XdsLb::LbChannelState::LrsCallState::OnInitialRequestSentLocked(
void* arg, grpc_error* error) {
LrsCallState* lrs_calld = static_cast<LrsCallState*>(arg);
// Clear the send_message_payload_.
grpc_byte_buffer_destroy(lrs_calld->send_message_payload_);
lrs_calld->send_message_payload_ = nullptr;
lrs_calld->MaybeStartReportingLocked();
lrs_calld->Unref(DEBUG_LOCATION, "LRS+OnInitialRequestSentLocked");
}
void XdsLb::LbChannelState::LrsCallState::OnResponseReceivedLocked(
void* arg, grpc_error* error) {
LrsCallState* lrs_calld = static_cast<LrsCallState*>(arg);
XdsLb* xdslb_policy = lrs_calld->xdslb_policy();
// Empty payload means the LB call was cancelled.
if (!lrs_calld->IsCurrentCallOnChannel() ||
lrs_calld->recv_message_payload_ == nullptr) {
lrs_calld->Unref(DEBUG_LOCATION, "LRS+OnResponseReceivedLocked");
return;
}
// Read the response.
grpc_byte_buffer_reader bbr;
grpc_byte_buffer_reader_init(&bbr, lrs_calld->recv_message_payload_);
grpc_slice response_slice = grpc_byte_buffer_reader_readall(&bbr);
grpc_byte_buffer_reader_destroy(&bbr);
grpc_byte_buffer_destroy(lrs_calld->recv_message_payload_);
lrs_calld->recv_message_payload_ = nullptr;
// This anonymous lambda is a hack to avoid the usage of goto.
[&]() {
// Parse the response.
UniquePtr<char> new_cluster_name;
grpc_millis new_load_reporting_interval;
grpc_error* parse_error = XdsLrsResponseDecodeAndParse(
response_slice, &new_cluster_name, &new_load_reporting_interval);
if (parse_error != GRPC_ERROR_NONE) {
gpr_log(GPR_ERROR, "[xdslb %p] LRS response parsing failed. error=%s",
xdslb_policy, grpc_error_string(parse_error));
GRPC_ERROR_UNREF(parse_error);
return;
}
lrs_calld->seen_response_ = true;
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO,
"[xdslb %p] LRS response received, cluster_name=%s, "
"load_report_interval=%" PRId64 "ms",
xdslb_policy, new_cluster_name.get(),
new_load_reporting_interval);
}
if (new_load_reporting_interval <
GRPC_XDS_MIN_CLIENT_LOAD_REPORTING_INTERVAL_MS) {
new_load_reporting_interval =
GRPC_XDS_MIN_CLIENT_LOAD_REPORTING_INTERVAL_MS;
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(
GPR_INFO,
"[xdslb %p] Increased load_report_interval to minimum value %dms",
xdslb_policy, GRPC_XDS_MIN_CLIENT_LOAD_REPORTING_INTERVAL_MS);
}
}
// Ignore identical update.
if (lrs_calld->load_reporting_interval_ == new_load_reporting_interval &&
strcmp(lrs_calld->cluster_name_.get(), new_cluster_name.get()) == 0) {
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO,
"[xdslb %p] Incoming LRS response identical to current, "
"ignoring.",
xdslb_policy);
}
return;
}
// Stop current load reporting (if any) to adopt the new config.
lrs_calld->reporter_.reset();
// Record the new config.
lrs_calld->cluster_name_ = std::move(new_cluster_name);
lrs_calld->load_reporting_interval_ = new_load_reporting_interval;
// Try starting sending load report.
lrs_calld->MaybeStartReportingLocked();
}();
grpc_slice_unref_internal(response_slice);
if (xdslb_policy->shutting_down_) {
lrs_calld->Unref(DEBUG_LOCATION,
"LRS+OnResponseReceivedLocked+xds_shutdown");
return;
}
// Keep listening for LRS config updates.
grpc_op op;
memset(&op, 0, sizeof(op));
op.op = GRPC_OP_RECV_MESSAGE;
op.data.recv_message.recv_message = &lrs_calld->recv_message_payload_;
op.flags = 0;
op.reserved = nullptr;
GPR_ASSERT(lrs_calld->lb_call_ != nullptr);
// Reuse the "OnResponseReceivedLocked" ref taken in ctor.
const grpc_call_error call_error = grpc_call_start_batch_and_execute(
lrs_calld->lb_call_, &op, 1, &lrs_calld->on_response_received_);
GPR_ASSERT(GRPC_CALL_OK == call_error);
}
void XdsLb::LbChannelState::LrsCallState::OnStatusReceivedLocked(
void* arg, grpc_error* error) {
LrsCallState* lrs_calld = static_cast<LrsCallState*>(arg);
XdsLb* xdslb_policy = lrs_calld->xdslb_policy();
LbChannelState* lb_chand = lrs_calld->lb_chand();
GPR_ASSERT(lrs_calld->lb_call_ != nullptr);
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
char* status_details = grpc_slice_to_c_string(lrs_calld->status_details_);
gpr_log(GPR_INFO,
"[xdslb %p] LRS call status received. Status = %d, details "
"= '%s', (lb_chand: %p, lb_calld: %p, lb_call: %p), error '%s'",
xdslb_policy, lrs_calld->status_code_, status_details, lb_chand,
lrs_calld, lrs_calld->lb_call_, grpc_error_string(error));
gpr_free(status_details);
}
// Ignore status from a stale call.
if (lrs_calld->IsCurrentCallOnChannel()) {
// Because this call is the current one on the channel, the channel can't
// have been swapped out; otherwise, the call should have been reset.
GPR_ASSERT(lb_chand->IsCurrentChannel() || lb_chand->IsPendingChannel());
GPR_ASSERT(!xdslb_policy->shutting_down_);
if (lb_chand == xdslb_policy->LatestLbChannel()) {
// This channel is the most recently created one. Try to restart the call
// and reresolve.
lrs_calld->parent_->OnCallFinishedLocked();
xdslb_policy->channel_control_helper()->RequestReresolution();
}
}
lrs_calld->Unref(DEBUG_LOCATION, "LRS+OnStatusReceivedLocked");
}
bool XdsLb::LbChannelState::LrsCallState::IsCurrentCallOnChannel() const {
// If the retryable LRS call is null (which only happens when the LB channel
// is shutting down), all the LRS calls are stale.
if (lb_chand()->lrs_calld_ == nullptr) return false;
return this == lb_chand()->lrs_calld_->lb_calld();
}
//
// helper code for creating balancer channel
//
// Returns the channel args for the LB channel, used to create a bidirectional
// stream for the reception of load balancing updates.
grpc_channel_args* BuildBalancerChannelArgs(const grpc_channel_args* args) {
static const char* args_to_remove[] = {
// LB policy name, since we want to use the default (pick_first) in
// the LB channel.
GRPC_ARG_LB_POLICY_NAME,
// The service config that contains the LB config. We don't want to
// recursively use xds in the LB channel.
GRPC_ARG_SERVICE_CONFIG,
// The channel arg for the server URI, since that will be different for
// the LB channel than for the parent channel. The client channel
// factory will re-add this arg with the right value.
GRPC_ARG_SERVER_URI,
// The LB channel should use the authority indicated by the target
// authority table (see \a ModifyXdsBalancerChannelArgs),
// as opposed to the authority from the parent channel.
GRPC_ARG_DEFAULT_AUTHORITY,
// Just as for \a GRPC_ARG_DEFAULT_AUTHORITY, the LB channel should be
// treated as a stand-alone channel and not inherit this argument from the
// args of the parent channel.
GRPC_SSL_TARGET_NAME_OVERRIDE_ARG,
// Don't want to pass down channelz node from parent; the balancer
// channel will get its own.
GRPC_ARG_CHANNELZ_CHANNEL_NODE,
};
// Channel args to add.
InlinedVector<grpc_arg, 2> args_to_add;
// A channel arg indicating the target is a xds load balancer.
args_to_add.emplace_back(grpc_channel_arg_integer_create(
const_cast<char*>(GRPC_ARG_ADDRESS_IS_XDS_LOAD_BALANCER), 1));
// The parent channel's channelz uuid.
channelz::ChannelNode* channelz_node = nullptr;
const grpc_arg* arg =
grpc_channel_args_find(args, GRPC_ARG_CHANNELZ_CHANNEL_NODE);
if (arg != nullptr && arg->type == GRPC_ARG_POINTER &&
arg->value.pointer.p != nullptr) {
channelz_node = static_cast<channelz::ChannelNode*>(arg->value.pointer.p);
args_to_add.emplace_back(
channelz::MakeParentUuidArg(channelz_node->uuid()));
}
// Construct channel args.
grpc_channel_args* new_args = grpc_channel_args_copy_and_add_and_remove(
args, args_to_remove, GPR_ARRAY_SIZE(args_to_remove), args_to_add.data(),
args_to_add.size());
// Make any necessary modifications for security.
return ModifyXdsBalancerChannelArgs(new_args);
}
//
// ctor and dtor
//
XdsLb::XdsLb(Args args)
: LoadBalancingPolicy(std::move(args)),
lb_call_timeout_ms_(grpc_channel_args_find_integer(
args.args, GRPC_ARG_GRPCLB_CALL_TIMEOUT_MS, {0, 0, INT_MAX})),
lb_fallback_timeout_ms_(grpc_channel_args_find_integer(
args.args, GRPC_ARG_XDS_FALLBACK_TIMEOUT_MS,
{GRPC_XDS_DEFAULT_FALLBACK_TIMEOUT_MS, 0, INT_MAX})),
locality_retention_interval_ms_(grpc_channel_args_find_integer(
args.args, GRPC_ARG_LOCALITY_RETENTION_INTERVAL_MS,
{GRPC_XDS_DEFAULT_LOCALITY_RETENTION_INTERVAL_MS, 0, INT_MAX})),
locality_map_failover_timeout_ms_(grpc_channel_args_find_integer(
args.args, GRPC_ARG_XDS_FAILOVER_TIMEOUT_MS,
{GRPC_XDS_DEFAULT_FAILOVER_TIMEOUT_MS, 0, INT_MAX})),
priority_list_(this) {
// Record server name.
const grpc_arg* arg = grpc_channel_args_find(args.args, GRPC_ARG_SERVER_URI);
const char* server_uri = grpc_channel_arg_get_string(arg);
GPR_ASSERT(server_uri != nullptr);
grpc_uri* uri = grpc_uri_parse(server_uri, true);
GPR_ASSERT(uri->path[0] != '\0');
server_name_ = gpr_strdup(uri->path[0] == '/' ? uri->path + 1 : uri->path);
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO,
"[xdslb %p] Will use '%s' as the server name for LB request.", this,
server_name_);
}
grpc_uri_destroy(uri);
}
XdsLb::~XdsLb() {
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO, "[xdslb %p] destroying xds LB policy", this);
}
gpr_free((void*)server_name_);
grpc_channel_args_destroy(args_);
}
void XdsLb::ShutdownLocked() {
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO, "[xdslb %p] shutting down", this);
}
shutting_down_ = true;
if (fallback_at_startup_checks_pending_) {
grpc_timer_cancel(&lb_fallback_timer_);
}
priority_list_.ShutdownLocked();
if (fallback_policy_ != nullptr) {
grpc_pollset_set_del_pollset_set(fallback_policy_->interested_parties(),
interested_parties());
}
if (pending_fallback_policy_ != nullptr) {
grpc_pollset_set_del_pollset_set(
pending_fallback_policy_->interested_parties(), interested_parties());
}
fallback_policy_.reset();
pending_fallback_policy_.reset();
// We reset the LB channels here instead of in our destructor because they
// hold refs to XdsLb.
lb_chand_.reset();
pending_lb_chand_.reset();
}
//
// public methods
//
void XdsLb::ResetBackoffLocked() {
if (lb_chand_ != nullptr) {
grpc_channel_reset_connect_backoff(lb_chand_->channel());
}
if (pending_lb_chand_ != nullptr) {
grpc_channel_reset_connect_backoff(pending_lb_chand_->channel());
}
priority_list_.ResetBackoffLocked();
if (fallback_policy_ != nullptr) {
fallback_policy_->ResetBackoffLocked();
}
if (pending_fallback_policy_ != nullptr) {
pending_fallback_policy_->ResetBackoffLocked();
}
}
void XdsLb::ProcessAddressesAndChannelArgsLocked(
ServerAddressList addresses, const grpc_channel_args& args) {
// Update fallback address list.
fallback_backend_addresses_ = std::move(addresses);
// Make sure that GRPC_ARG_LB_POLICY_NAME is set in channel args,
// since we use this to trigger the client_load_reporting filter.
static const char* args_to_remove[] = {GRPC_ARG_LB_POLICY_NAME};
grpc_arg new_arg = grpc_channel_arg_string_create(
(char*)GRPC_ARG_LB_POLICY_NAME, (char*)"xds");
grpc_channel_args_destroy(args_);
args_ = grpc_channel_args_copy_and_add_and_remove(
&args, args_to_remove, GPR_ARRAY_SIZE(args_to_remove), &new_arg, 1);
// Construct args for balancer channel.
grpc_channel_args* lb_channel_args = BuildBalancerChannelArgs(&args);
// Create an LB channel if we don't have one yet or the balancer name has
// changed from the last received one.
bool create_lb_channel = lb_chand_ == nullptr;
if (lb_chand_ != nullptr) {
UniquePtr<char> last_balancer_name(
grpc_channel_get_target(LatestLbChannel()->channel()));
create_lb_channel =
strcmp(last_balancer_name.get(), balancer_name_.get()) != 0;
}
if (create_lb_channel) {
OrphanablePtr<LbChannelState> lb_chand = MakeOrphanable<LbChannelState>(
Ref(DEBUG_LOCATION, "XdsLb+LbChannelState"), balancer_name_.get(),
*lb_channel_args);
if (lb_chand_ == nullptr || !lb_chand_->HasActiveEdsCall()) {
GPR_ASSERT(pending_lb_chand_ == nullptr);
// If we do not have a working LB channel yet, use the newly created one.
lb_chand_ = std::move(lb_chand);
} else {
// Otherwise, wait until the new LB channel to be ready to swap it in.
pending_lb_chand_ = std::move(lb_chand);
}
}
grpc_channel_args_destroy(lb_channel_args);
}
void XdsLb::ParseLbConfig(const ParsedXdsConfig* xds_config) {
if (xds_config == nullptr || xds_config->balancer_name() == nullptr) return;
// TODO(yashykt) : does this need to be a gpr_strdup
// TODO(juanlishen): Read balancer name from bootstrap file.
balancer_name_ = UniquePtr<char>(gpr_strdup(xds_config->balancer_name()));
child_policy_config_ = xds_config->child_policy();
fallback_policy_config_ = xds_config->fallback_policy();
}
void XdsLb::UpdateLocked(UpdateArgs args) {
const bool is_initial_update = lb_chand_ == nullptr;
ParseLbConfig(static_cast<const ParsedXdsConfig*>(args.config.get()));
if (balancer_name_ == nullptr) {
gpr_log(GPR_ERROR, "[xdslb %p] LB config parsing fails.", this);
return;
}
ProcessAddressesAndChannelArgsLocked(std::move(args.addresses), *args.args);
priority_list_.UpdateLocked();
// Update the existing fallback policy. The fallback policy config and/or the
// fallback addresses may be new.
if (fallback_policy_ != nullptr) UpdateFallbackPolicyLocked();
// If this is the initial update, start the fallback-at-startup checks.
if (is_initial_update) {
grpc_millis deadline = ExecCtx::Get()->Now() + lb_fallback_timeout_ms_;
Ref(DEBUG_LOCATION, "on_fallback_timer").release(); // Held by closure
GRPC_CLOSURE_INIT(&lb_on_fallback_, &XdsLb::OnFallbackTimerLocked, this,
grpc_combiner_scheduler(combiner()));
fallback_at_startup_checks_pending_ = true;
grpc_timer_init(&lb_fallback_timer_, deadline, &lb_on_fallback_);
// Start watching the channel's connectivity state. If the channel
// goes into state TRANSIENT_FAILURE, we go into fallback mode even if
// the fallback timeout has not elapsed.
lb_chand_->StartConnectivityWatchLocked();
}
}
//
// fallback-related methods
//
void XdsLb::MaybeCancelFallbackAtStartupChecks() {
if (!fallback_at_startup_checks_pending_) return;
gpr_log(GPR_INFO,
"[xdslb %p] Cancelling fallback timer and LB channel connectivity "
"watch",
this);
grpc_timer_cancel(&lb_fallback_timer_);
lb_chand_->CancelConnectivityWatchLocked();
fallback_at_startup_checks_pending_ = false;
}
void XdsLb::OnFallbackTimerLocked(void* arg, grpc_error* error) {
XdsLb* xdslb_policy = static_cast<XdsLb*>(arg);
// If some fallback-at-startup check is done after the timer fires but before
// this callback actually runs, don't fall back.
if (xdslb_policy->fallback_at_startup_checks_pending_ &&
!xdslb_policy->shutting_down_ && error == GRPC_ERROR_NONE) {
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO,
"[xdslb %p] Child policy not ready after fallback timeout; "
"entering fallback mode",
xdslb_policy);
}
xdslb_policy->fallback_at_startup_checks_pending_ = false;
xdslb_policy->UpdateFallbackPolicyLocked();
xdslb_policy->lb_chand_->CancelConnectivityWatchLocked();
}
xdslb_policy->Unref(DEBUG_LOCATION, "on_fallback_timer");
}
void XdsLb::UpdateFallbackPolicyLocked() {
if (shutting_down_) return;
// Construct update args.
UpdateArgs update_args;
update_args.addresses = fallback_backend_addresses_;
update_args.config = fallback_policy_config_ == nullptr
? nullptr
: fallback_policy_config_->Ref();
update_args.args = grpc_channel_args_copy(args_);
// If the child policy name changes, we need to create a new child
// policy. When this happens, we leave child_policy_ as-is and store
// the new child policy in pending_child_policy_. Once the new child
// policy transitions into state READY, we swap it into child_policy_,
// replacing the original child policy. So pending_child_policy_ is
// non-null only between when we apply an update that changes the child
// policy name and when the new child reports state READY.
//
// Updates can arrive at any point during this transition. We always
// apply updates relative to the most recently created child policy,
// even if the most recent one is still in pending_child_policy_. This
// is true both when applying the updates to an existing child policy
// and when determining whether we need to create a new policy.
//
// As a result of this, there are several cases to consider here:
//
// 1. We have no existing child policy (i.e., we have started up but
// have not yet received a serverlist from the balancer or gone
// into fallback mode; in this case, both child_policy_ and
// pending_child_policy_ are null). In this case, we create a
// new child policy and store it in child_policy_.
//
// 2. We have an existing child policy and have no pending child policy
// from a previous update (i.e., either there has not been a
// previous update that changed the policy name, or we have already
// finished swapping in the new policy; in this case, child_policy_
// is non-null but pending_child_policy_ is null). In this case:
// a. If child_policy_->name() equals child_policy_name, then we
// update the existing child policy.
// b. If child_policy_->name() does not equal child_policy_name,
// we create a new policy. The policy will be stored in
// pending_child_policy_ and will later be swapped into
// child_policy_ by the helper when the new child transitions
// into state READY.
//
// 3. We have an existing child policy and have a pending child policy
// from a previous update (i.e., a previous update set
// pending_child_policy_ as per case 2b above and that policy has
// not yet transitioned into state READY and been swapped into
// child_policy_; in this case, both child_policy_ and
// pending_child_policy_ are non-null). In this case:
// a. If pending_child_policy_->name() equals child_policy_name,
// then we update the existing pending child policy.
// b. If pending_child_policy->name() does not equal
// child_policy_name, then we create a new policy. The new
// policy is stored in pending_child_policy_ (replacing the one
// that was there before, which will be immediately shut down)
// and will later be swapped into child_policy_ by the helper
// when the new child transitions into state READY.
const char* fallback_policy_name = fallback_policy_config_ == nullptr
? "round_robin"
: fallback_policy_config_->name();
const bool create_policy =
// case 1
fallback_policy_ == nullptr ||
// case 2b
(pending_fallback_policy_ == nullptr &&
strcmp(fallback_policy_->name(), fallback_policy_name) != 0) ||
// case 3b
(pending_fallback_policy_ != nullptr &&
strcmp(pending_fallback_policy_->name(), fallback_policy_name) != 0);
LoadBalancingPolicy* policy_to_update = nullptr;
if (create_policy) {
// Cases 1, 2b, and 3b: create a new child policy.
// If child_policy_ is null, we set it (case 1), else we set
// pending_child_policy_ (cases 2b and 3b).
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO, "[xdslb %p] Creating new %sfallback policy %s", this,
fallback_policy_ == nullptr ? "" : "pending ",
fallback_policy_name);
}
auto& lb_policy = fallback_policy_ == nullptr ? fallback_policy_
: pending_fallback_policy_;
lb_policy =
CreateFallbackPolicyLocked(fallback_policy_name, update_args.args);
policy_to_update = lb_policy.get();
} else {
// Cases 2a and 3a: update an existing policy.
// If we have a pending child policy, send the update to the pending
// policy (case 3a), else send it to the current policy (case 2a).
policy_to_update = pending_fallback_policy_ != nullptr
? pending_fallback_policy_.get()
: fallback_policy_.get();
}
GPR_ASSERT(policy_to_update != nullptr);
// Update the policy.
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(
GPR_INFO, "[xdslb %p] Updating %sfallback policy %p", this,
policy_to_update == pending_fallback_policy_.get() ? "pending " : "",
policy_to_update);
}
policy_to_update->UpdateLocked(std::move(update_args));
}
OrphanablePtr<LoadBalancingPolicy> XdsLb::CreateFallbackPolicyLocked(
const char* name, const grpc_channel_args* args) {
FallbackHelper* helper =
New<FallbackHelper>(Ref(DEBUG_LOCATION, "FallbackHelper"));
LoadBalancingPolicy::Args lb_policy_args;
lb_policy_args.combiner = combiner();
lb_policy_args.args = args;
lb_policy_args.channel_control_helper =
UniquePtr<ChannelControlHelper>(helper);
OrphanablePtr<LoadBalancingPolicy> lb_policy =
LoadBalancingPolicyRegistry::CreateLoadBalancingPolicy(
name, std::move(lb_policy_args));
if (GPR_UNLIKELY(lb_policy == nullptr)) {
gpr_log(GPR_ERROR, "[xdslb %p] Failure creating fallback policy %s", this,
name);
return nullptr;
}
helper->set_child(lb_policy.get());
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO, "[xdslb %p] Created new fallback policy %s (%p)", this,
name, lb_policy.get());
}
// Add the xDS's interested_parties pollset_set to that of the newly created
// child policy. This will make the child policy progress upon activity on xDS
// LB, which in turn is tied to the application's call.
grpc_pollset_set_add_pollset_set(lb_policy->interested_parties(),
interested_parties());
return lb_policy;
}
void XdsLb::MaybeExitFallbackMode() {
if (fallback_policy_ == nullptr) return;
gpr_log(GPR_INFO, "[xdslb %p] Exiting fallback mode", this);
fallback_policy_.reset();
pending_fallback_policy_.reset();
}
//
// XdsLb::PriorityList
//
void XdsLb::PriorityList::UpdateLocked() {
const auto& priority_list_update = xds_policy_->priority_list_update_;
// 1. Remove from the priority list the priorities that are not in the update.
DeactivatePrioritiesLowerThan(priority_list_update.LowestPriority());
// 2. Update all the existing priorities.
for (uint32_t priority = 0; priority < priorities_.size(); ++priority) {
LocalityMap* locality_map = priorities_[priority].get();
const auto* locality_map_update = priority_list_update.Find(priority);
// Propagate locality_map_update.
// TODO(juanlishen): Find a clean way to skip duplicate update for a
// priority.
locality_map->UpdateLocked(*locality_map_update);
}
// 3. Only create a new locality map if all the existing ones have failed.
if (priorities_.empty() ||
!priorities_[priorities_.size() - 1]->failover_timer_callback_pending()) {
const uint32_t new_priority = static_cast<uint32_t>(priorities_.size());
// Create a new locality map. Note that in some rare cases (e.g., the
// locality map reports TRANSIENT_FAILURE synchronously due to subchannel
// sharing), the following invocation may result in multiple locality maps
// to be created.
MaybeCreateLocalityMapLocked(new_priority);
}
}
void XdsLb::PriorityList::ResetBackoffLocked() {
for (size_t i = 0; i < priorities_.size(); ++i) {
priorities_[i]->ResetBackoffLocked();
}
}
void XdsLb::PriorityList::ShutdownLocked() { priorities_.clear(); }
void XdsLb::PriorityList::UpdateXdsPickerLocked() {
// If we are in fallback mode, don't generate an xds picker from localities.
if (xds_policy_->fallback_policy_ != nullptr) return;
if (current_priority() == UINT32_MAX) {
grpc_error* error = grpc_error_set_int(
GRPC_ERROR_CREATE_FROM_STATIC_STRING("no ready locality map"),
GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNAVAILABLE);
xds_policy_->channel_control_helper()->UpdateState(
GRPC_CHANNEL_TRANSIENT_FAILURE,
UniquePtr<SubchannelPicker>(New<TransientFailurePicker>(error)));
return;
}
priorities_[current_priority_]->UpdateXdsPickerLocked();
}
void XdsLb::PriorityList::MaybeCreateLocalityMapLocked(uint32_t priority) {
// Exhausted priorities in the update.
if (!priority_list_update().Contains(priority)) return;
auto new_locality_map = New<LocalityMap>(
xds_policy_->Ref(DEBUG_LOCATION, "XdsLb+LocalityMap"), priority);
priorities_.emplace_back(OrphanablePtr<LocalityMap>(new_locality_map));
new_locality_map->UpdateLocked(*priority_list_update().Find(priority));
}
void XdsLb::PriorityList::FailoverOnConnectionFailureLocked() {
const uint32_t failed_priority = LowestPriority();
// If we're failing over from the lowest priority, report TRANSIENT_FAILURE.
if (failed_priority == priority_list_update().LowestPriority()) {
UpdateXdsPickerLocked();
}
MaybeCreateLocalityMapLocked(failed_priority + 1);
}
void XdsLb::PriorityList::FailoverOnDisconnectionLocked(
uint32_t failed_priority) {
current_priority_ = UINT32_MAX;
for (uint32_t next_priority = failed_priority + 1;
next_priority <= priority_list_update().LowestPriority();
++next_priority) {
if (!Contains(next_priority)) {
MaybeCreateLocalityMapLocked(next_priority);
return;
}
if (priorities_[next_priority]->MaybeReactivateLocked()) return;
}
}
void XdsLb::PriorityList::SwitchToHigherPriorityLocked(uint32_t priority) {
current_priority_ = priority;
DeactivatePrioritiesLowerThan(current_priority_);
UpdateXdsPickerLocked();
}
void XdsLb::PriorityList::DeactivatePrioritiesLowerThan(uint32_t priority) {
if (priorities_.empty()) return;
// Deactivate the locality maps from the lowest priority.
for (uint32_t p = LowestPriority(); p > priority; --p) {
if (xds_policy_->locality_retention_interval_ms_ == 0) {
priorities_.pop_back();
} else {
priorities_[p]->DeactivateLocked();
}
}
}
OrphanablePtr<XdsLb::PriorityList::LocalityMap::Locality>
XdsLb::PriorityList::ExtractLocalityLocked(
const RefCountedPtr<XdsLocalityName>& name, uint32_t exclude_priority) {
for (uint32_t priority = 0; priority < priorities_.size(); ++priority) {
if (priority == exclude_priority) continue;
LocalityMap* locality_map = priorities_[priority].get();
auto locality = locality_map->ExtractLocalityLocked(name);
if (locality != nullptr) return locality;
}
return nullptr;
}
//
// XdsLb::PriorityList::LocalityMap
//
XdsLb::PriorityList::LocalityMap::LocalityMap(RefCountedPtr<XdsLb> xds_policy,
uint32_t priority)
: xds_policy_(std::move(xds_policy)), priority_(priority) {
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO, "[xdslb %p] Creating priority %" PRIu32,
xds_policy_.get(), priority_);
}
GRPC_CLOSURE_INIT(&on_delayed_removal_timer_, OnDelayedRemovalTimerLocked,
this, grpc_combiner_scheduler(xds_policy_->combiner()));
GRPC_CLOSURE_INIT(&on_failover_timer_, OnFailoverTimerLocked, this,
grpc_combiner_scheduler(xds_policy_->combiner()));
// Start the failover timer.
Ref(DEBUG_LOCATION, "LocalityMap+OnFailoverTimerLocked").release();
grpc_timer_init(
&failover_timer_,
ExecCtx::Get()->Now() + xds_policy_->locality_map_failover_timeout_ms_,
&on_failover_timer_);
failover_timer_callback_pending_ = true;
// This is the first locality map ever created, report CONNECTING.
if (priority_ == 0) {
xds_policy_->channel_control_helper()->UpdateState(
GRPC_CHANNEL_CONNECTING,
UniquePtr<SubchannelPicker>(
New<QueuePicker>(xds_policy_->Ref(DEBUG_LOCATION, "QueuePicker"))));
}
}
void XdsLb::PriorityList::LocalityMap::UpdateLocked(
const XdsPriorityListUpdate::LocalityMap& locality_map_update) {
if (xds_policy_->shutting_down_) return;
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO, "[xdslb %p] Start Updating priority %" PRIu32,
xds_policy(), priority_);
}
// Maybe reactivate the locality map in case all the active locality maps have
// failed.
MaybeReactivateLocked();
// Remove (later) the localities not in locality_map_update.
for (auto iter = localities_.begin(); iter != localities_.end();) {
const auto& name = iter->first;
Locality* locality = iter->second.get();
if (locality_map_update.Contains(name)) {
++iter;
continue;
}
if (xds_policy()->locality_retention_interval_ms_ == 0) {
iter = localities_.erase(iter);
} else {
locality->DeactivateLocked();
++iter;
}
}
// Add or update the localities in locality_map_update.
for (const auto& p : locality_map_update.localities) {
const auto& name = p.first;
const auto& locality_update = p.second;
OrphanablePtr<Locality>& locality = localities_[name];
if (locality == nullptr) {
// Move from another locality map if possible.
locality = priority_list()->ExtractLocalityLocked(name, priority_);
if (locality != nullptr) {
locality->set_locality_map(
Ref(DEBUG_LOCATION, "LocalityMap+Locality_move"));
} else {
locality = MakeOrphanable<Locality>(
Ref(DEBUG_LOCATION, "LocalityMap+Locality"), name);
}
}
// Keep a copy of serverlist in the update so that we can compare it
// with the future ones.
locality->UpdateLocked(locality_update.lb_weight,
locality_update.serverlist);
}
}
void XdsLb::PriorityList::LocalityMap::ResetBackoffLocked() {
for (auto& p : localities_) p.second->ResetBackoffLocked();
}
void XdsLb::PriorityList::LocalityMap::UpdateXdsPickerLocked() {
// Construct a new xds picker which maintains a map of all locality pickers
// that are ready. Each locality is represented by a portion of the range
// proportional to its weight, such that the total range is the sum of the
// weights of all localities.
Picker::PickerList picker_list;
uint32_t end = 0;
for (const auto& p : localities_) {
const auto& locality_name = p.first;
const Locality* locality = p.second.get();
// Skip the localities that are not in the latest locality map update.
if (!locality_map_update()->Contains(locality_name)) continue;
if (locality->connectivity_state() != GRPC_CHANNEL_READY) continue;
end += locality->weight();
picker_list.push_back(MakePair(end, locality->picker_wrapper()));
}
xds_policy()->channel_control_helper()->UpdateState(
GRPC_CHANNEL_READY, UniquePtr<SubchannelPicker>(New<Picker>(
xds_policy_->Ref(DEBUG_LOCATION, "XdsLb+Picker"),
std::move(picker_list))));
}
OrphanablePtr<XdsLb::PriorityList::LocalityMap::Locality>
XdsLb::PriorityList::LocalityMap::ExtractLocalityLocked(
const RefCountedPtr<XdsLocalityName>& name) {
for (auto iter = localities_.begin(); iter != localities_.end(); ++iter) {
const auto& name_in_map = iter->first;
if (*name_in_map == *name) {
auto locality = std::move(iter->second);
localities_.erase(iter);
return locality;
}
}
return nullptr;
}
void XdsLb::PriorityList::LocalityMap::DeactivateLocked() {
// If already deactivated, don't do it again.
if (delayed_removal_timer_callback_pending_) return;
MaybeCancelFailoverTimerLocked();
// Start a timer to delete the locality.
Ref(DEBUG_LOCATION, "LocalityMap+timer").release();
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO,
"[xdslb %p] Will remove priority %" PRIu32 " in %" PRId64 " ms.",
xds_policy(), priority_,
xds_policy()->locality_retention_interval_ms_);
}
grpc_timer_init(
&delayed_removal_timer_,
ExecCtx::Get()->Now() + xds_policy()->locality_retention_interval_ms_,
&on_delayed_removal_timer_);
delayed_removal_timer_callback_pending_ = true;
}
bool XdsLb::PriorityList::LocalityMap::MaybeReactivateLocked() {
// Don't reactivate a priority that is not higher than the current one.
if (priority_ >= priority_list()->current_priority()) return false;
// Reactivate this priority by cancelling deletion timer.
if (delayed_removal_timer_callback_pending_) {
grpc_timer_cancel(&delayed_removal_timer_);
}
// Switch to this higher priority if it's READY.
if (connectivity_state_ != GRPC_CHANNEL_READY) return false;
priority_list()->SwitchToHigherPriorityLocked(priority_);
return true;
}
void XdsLb::PriorityList::LocalityMap::MaybeCancelFailoverTimerLocked() {
if (failover_timer_callback_pending_) grpc_timer_cancel(&failover_timer_);
}
void XdsLb::PriorityList::LocalityMap::Orphan() {
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO, "[xdslb %p] Priority %" PRIu32 " orphaned.", xds_policy(),
priority_);
}
MaybeCancelFailoverTimerLocked();
if (delayed_removal_timer_callback_pending_) {
grpc_timer_cancel(&delayed_removal_timer_);
}
localities_.clear();
Unref(DEBUG_LOCATION, "LocalityMap+Orphan");
}
void XdsLb::PriorityList::LocalityMap::OnLocalityStateUpdateLocked() {
UpdateConnectivityStateLocked();
// Ignore priorities not in priority_list_update.
if (!priority_list_update().Contains(priority_)) return;
const uint32_t current_priority = priority_list()->current_priority();
// Ignore lower-than-current priorities.
if (priority_ > current_priority) return;
// Maybe update fallback state.
if (connectivity_state_ == GRPC_CHANNEL_READY) {
xds_policy_->MaybeCancelFallbackAtStartupChecks();
xds_policy_->MaybeExitFallbackMode();
}
// Update is for a higher-than-current priority. (Special case: update is for
// any active priority if there is no current priority.)
if (priority_ < current_priority) {
if (connectivity_state_ == GRPC_CHANNEL_READY) {
MaybeCancelFailoverTimerLocked();
// If a higher-than-current priority becomes READY, switch to use it.
priority_list()->SwitchToHigherPriorityLocked(priority_);
} else if (connectivity_state_ == GRPC_CHANNEL_TRANSIENT_FAILURE) {
// If a higher-than-current priority becomes TRANSIENT_FAILURE, only
// handle it if it's the priority that is still in failover timeout.
if (failover_timer_callback_pending_) {
MaybeCancelFailoverTimerLocked();
priority_list()->FailoverOnConnectionFailureLocked();
}
}
return;
}
// Update is for current priority.
if (connectivity_state_ != GRPC_CHANNEL_READY) {
// Fail over if it's no longer READY.
priority_list()->FailoverOnDisconnectionLocked(priority_);
}
// At this point, one of the following things has happened to the current
// priority.
// 1. It remained the same (but received picker update from its localities).
// 2. It changed to a lower priority due to failover.
// 3. It became invalid because failover didn't yield a READY priority.
// In any case, update the xds picker.
priority_list()->UpdateXdsPickerLocked();
}
void XdsLb::PriorityList::LocalityMap::UpdateConnectivityStateLocked() {
size_t num_ready = 0;
size_t num_connecting = 0;
size_t num_idle = 0;
size_t num_transient_failures = 0;
for (const auto& p : localities_) {
const auto& locality_name = p.first;
const Locality* locality = p.second.get();
// Skip the localities that are not in the latest locality map update.
if (!locality_map_update()->Contains(locality_name)) continue;
switch (locality->connectivity_state()) {
case GRPC_CHANNEL_READY: {
++num_ready;
break;
}
case GRPC_CHANNEL_CONNECTING: {
++num_connecting;
break;
}
case GRPC_CHANNEL_IDLE: {
++num_idle;
break;
}
case GRPC_CHANNEL_TRANSIENT_FAILURE: {
++num_transient_failures;
break;
}
default:
GPR_UNREACHABLE_CODE(return );
}
}
if (num_ready > 0) {
connectivity_state_ = GRPC_CHANNEL_READY;
} else if (num_connecting > 0) {
connectivity_state_ = GRPC_CHANNEL_CONNECTING;
} else if (num_idle > 0) {
connectivity_state_ = GRPC_CHANNEL_IDLE;
} else {
connectivity_state_ = GRPC_CHANNEL_TRANSIENT_FAILURE;
}
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO,
"[xdslb %p] Priority %" PRIu32 " (%p) connectivity changed to %s",
xds_policy(), priority_, this,
grpc_connectivity_state_name(connectivity_state_));
}
}
void XdsLb::PriorityList::LocalityMap::OnDelayedRemovalTimerLocked(
void* arg, grpc_error* error) {
LocalityMap* self = static_cast<LocalityMap*>(arg);
self->delayed_removal_timer_callback_pending_ = false;
if (error == GRPC_ERROR_NONE && !self->xds_policy_->shutting_down_) {
auto* priority_list = self->priority_list();
const bool keep = self->priority_list_update().Contains(self->priority_) &&
self->priority_ <= priority_list->current_priority();
if (!keep) {
// This check is to make sure we always delete the locality maps from the
// lowest priority even if the closures of the back-to-back timers are not
// run in FIFO order.
// TODO(juanlishen): Eliminate unnecessary maintenance overhead for some
// deactivated locality maps when out-of-order closures are run.
// TODO(juanlishen): Check the timer implementation to see if this defense
// is necessary.
if (self->priority_ == priority_list->LowestPriority()) {
priority_list->priorities_.pop_back();
} else {
gpr_log(GPR_ERROR,
"[xdslb %p] Priority %" PRIu32
" is not the lowest priority (highest numeric value) but is "
"attempted to be deleted.",
self->xds_policy(), self->priority_);
}
}
}
self->Unref(DEBUG_LOCATION, "LocalityMap+timer");
}
void XdsLb::PriorityList::LocalityMap::OnFailoverTimerLocked(
void* arg, grpc_error* error) {
LocalityMap* self = static_cast<LocalityMap*>(arg);
self->failover_timer_callback_pending_ = false;
if (error == GRPC_ERROR_NONE && !self->xds_policy_->shutting_down_) {
self->priority_list()->FailoverOnConnectionFailureLocked();
}
self->Unref(DEBUG_LOCATION, "LocalityMap+OnFailoverTimerLocked");
}
//
// XdsLb::PriorityList::LocalityMap::Locality
//
XdsLb::PriorityList::LocalityMap::Locality::Locality(
RefCountedPtr<LocalityMap> locality_map,
RefCountedPtr<XdsLocalityName> name)
: locality_map_(std::move(locality_map)), name_(std::move(name)) {
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO, "[xdslb %p] created Locality %p for %s", xds_policy(),
this, name_->AsHumanReadableString());
}
GRPC_CLOSURE_INIT(&on_delayed_removal_timer_, OnDelayedRemovalTimerLocked,
this, grpc_combiner_scheduler(xds_policy()->combiner()));
}
XdsLb::PriorityList::LocalityMap::Locality::~Locality() {
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO, "[xdslb %p] Locality %p %s: destroying locality",
xds_policy(), this, name_->AsHumanReadableString());
}
locality_map_.reset(DEBUG_LOCATION, "Locality");
}
grpc_channel_args*
XdsLb::PriorityList::LocalityMap::Locality::CreateChildPolicyArgsLocked(
const grpc_channel_args* args_in) {
const grpc_arg args_to_add[] = {
// A channel arg indicating if the target is a backend inferred from a
// grpclb load balancer.
grpc_channel_arg_integer_create(
const_cast<char*>(GRPC_ARG_ADDRESS_IS_BACKEND_FROM_XDS_LOAD_BALANCER),
1),
// Inhibit client-side health checking, since the balancer does
// this for us.
grpc_channel_arg_integer_create(
const_cast<char*>(GRPC_ARG_INHIBIT_HEALTH_CHECKING), 1),
};
return grpc_channel_args_copy_and_add(args_in, args_to_add,
GPR_ARRAY_SIZE(args_to_add));
}
OrphanablePtr<LoadBalancingPolicy>
XdsLb::PriorityList::LocalityMap::Locality::CreateChildPolicyLocked(
const char* name, const grpc_channel_args* args) {
Helper* helper = New<Helper>(this->Ref(DEBUG_LOCATION, "Helper"));
LoadBalancingPolicy::Args lb_policy_args;
lb_policy_args.combiner = xds_policy()->combiner();
lb_policy_args.args = args;
lb_policy_args.channel_control_helper =
UniquePtr<ChannelControlHelper>(helper);
OrphanablePtr<LoadBalancingPolicy> lb_policy =
LoadBalancingPolicyRegistry::CreateLoadBalancingPolicy(
name, std::move(lb_policy_args));
if (GPR_UNLIKELY(lb_policy == nullptr)) {
gpr_log(GPR_ERROR,
"[xdslb %p] Locality %p %s: failure creating child policy %s",
locality_map_.get(), this, name_->AsHumanReadableString(), name);
return nullptr;
}
helper->set_child(lb_policy.get());
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO,
"[xdslb %p] Locality %p %s: Created new child policy %s (%p)",
locality_map_.get(), this, name_->AsHumanReadableString(), name,
lb_policy.get());
}
// Add the xDS's interested_parties pollset_set to that of the newly created
// child policy. This will make the child policy progress upon activity on xDS
// LB, which in turn is tied to the application's call.
grpc_pollset_set_add_pollset_set(lb_policy->interested_parties(),
xds_policy()->interested_parties());
return lb_policy;
}
void XdsLb::PriorityList::LocalityMap::Locality::UpdateLocked(
uint32_t locality_weight, ServerAddressList serverlist) {
if (xds_policy()->shutting_down_) return;
// Update locality weight.
weight_ = locality_weight;
if (delayed_removal_timer_callback_pending_) {
grpc_timer_cancel(&delayed_removal_timer_);
}
// Construct update args.
UpdateArgs update_args;
update_args.addresses = std::move(serverlist);
update_args.config = xds_policy()->child_policy_config_ == nullptr
? nullptr
: xds_policy()->child_policy_config_->Ref();
update_args.args = CreateChildPolicyArgsLocked(xds_policy()->args_);
// If the child policy name changes, we need to create a new child
// policy. When this happens, we leave child_policy_ as-is and store
// the new child policy in pending_child_policy_. Once the new child
// policy transitions into state READY, we swap it into child_policy_,
// replacing the original child policy. So pending_child_policy_ is
// non-null only between when we apply an update that changes the child
// policy name and when the new child reports state READY.
//
// Updates can arrive at any point during this transition. We always
// apply updates relative to the most recently created child policy,
// even if the most recent one is still in pending_child_policy_. This
// is true both when applying the updates to an existing child policy
// and when determining whether we need to create a new policy.
//
// As a result of this, there are several cases to consider here:
//
// 1. We have no existing child policy (i.e., we have started up but
// have not yet received a serverlist from the balancer or gone
// into fallback mode; in this case, both child_policy_ and
// pending_child_policy_ are null). In this case, we create a
// new child policy and store it in child_policy_.
//
// 2. We have an existing child policy and have no pending child policy
// from a previous update (i.e., either there has not been a
// previous update that changed the policy name, or we have already
// finished swapping in the new policy; in this case, child_policy_
// is non-null but pending_child_policy_ is null). In this case:
// a. If child_policy_->name() equals child_policy_name, then we
// update the existing child policy.
// b. If child_policy_->name() does not equal child_policy_name,
// we create a new policy. The policy will be stored in
// pending_child_policy_ and will later be swapped into
// child_policy_ by the helper when the new child transitions
// into state READY.
//
// 3. We have an existing child policy and have a pending child policy
// from a previous update (i.e., a previous update set
// pending_child_policy_ as per case 2b above and that policy has
// not yet transitioned into state READY and been swapped into
// child_policy_; in this case, both child_policy_ and
// pending_child_policy_ are non-null). In this case:
// a. If pending_child_policy_->name() equals child_policy_name,
// then we update the existing pending child policy.
// b. If pending_child_policy->name() does not equal
// child_policy_name, then we create a new policy. The new
// policy is stored in pending_child_policy_ (replacing the one
// that was there before, which will be immediately shut down)
// and will later be swapped into child_policy_ by the helper
// when the new child transitions into state READY.
// TODO(juanlishen): If the child policy is not configured via service config,
// use whatever algorithm is specified by the balancer.
const char* child_policy_name =
xds_policy()->child_policy_config_ == nullptr
? "round_robin"
: xds_policy()->child_policy_config_->name();
const bool create_policy =
// case 1
child_policy_ == nullptr ||
// case 2b
(pending_child_policy_ == nullptr &&
strcmp(child_policy_->name(), child_policy_name) != 0) ||
// case 3b
(pending_child_policy_ != nullptr &&
strcmp(pending_child_policy_->name(), child_policy_name) != 0);
LoadBalancingPolicy* policy_to_update = nullptr;
if (create_policy) {
// Cases 1, 2b, and 3b: create a new child policy.
// If child_policy_ is null, we set it (case 1), else we set
// pending_child_policy_ (cases 2b and 3b).
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO,
"[xdslb %p] Locality %p %s: Creating new %schild policy %s",
locality_map_.get(), this, name_->AsHumanReadableString(),
child_policy_ == nullptr ? "" : "pending ", child_policy_name);
}
auto& lb_policy =
child_policy_ == nullptr ? child_policy_ : pending_child_policy_;
lb_policy = CreateChildPolicyLocked(child_policy_name, update_args.args);
policy_to_update = lb_policy.get();
} else {
// Cases 2a and 3a: update an existing policy.
// If we have a pending child policy, send the update to the pending
// policy (case 3a), else send it to the current policy (case 2a).
policy_to_update = pending_child_policy_ != nullptr
? pending_child_policy_.get()
: child_policy_.get();
}
GPR_ASSERT(policy_to_update != nullptr);
// Update the policy.
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO, "[xdslb %p] Locality %p %s: Updating %schild policy %p",
locality_map_.get(), this, name_->AsHumanReadableString(),
policy_to_update == pending_child_policy_.get() ? "pending " : "",
policy_to_update);
}
policy_to_update->UpdateLocked(std::move(update_args));
}
void XdsLb::PriorityList::LocalityMap::Locality::ShutdownLocked() {
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO, "[xdslb %p] Locality %p %s: shutting down locality",
locality_map_.get(), this, name_->AsHumanReadableString());
}
// Remove the child policy's interested_parties pollset_set from the
// xDS policy.
grpc_pollset_set_del_pollset_set(child_policy_->interested_parties(),
xds_policy()->interested_parties());
child_policy_.reset();
if (pending_child_policy_ != nullptr) {
grpc_pollset_set_del_pollset_set(
pending_child_policy_->interested_parties(),
xds_policy()->interested_parties());
pending_child_policy_.reset();
}
// Drop our ref to the child's picker, in case it's holding a ref to
// the child.
picker_wrapper_.reset();
if (delayed_removal_timer_callback_pending_) {
grpc_timer_cancel(&delayed_removal_timer_);
}
shutdown_ = true;
}
void XdsLb::PriorityList::LocalityMap::Locality::ResetBackoffLocked() {
child_policy_->ResetBackoffLocked();
if (pending_child_policy_ != nullptr) {
pending_child_policy_->ResetBackoffLocked();
}
}
void XdsLb::PriorityList::LocalityMap::Locality::Orphan() {
ShutdownLocked();
Unref();
}
void XdsLb::PriorityList::LocalityMap::Locality::DeactivateLocked() {
// If already deactivated, don't do that again.
if (weight_ == 0) return;
// Set the locality weight to 0 so that future xds picker won't contain this
// locality.
weight_ = 0;
// Start a timer to delete the locality.
Ref(DEBUG_LOCATION, "Locality+timer").release();
grpc_timer_init(
&delayed_removal_timer_,
ExecCtx::Get()->Now() + xds_policy()->locality_retention_interval_ms_,
&on_delayed_removal_timer_);
delayed_removal_timer_callback_pending_ = true;
}
void XdsLb::PriorityList::LocalityMap::Locality::OnDelayedRemovalTimerLocked(
void* arg, grpc_error* error) {
Locality* self = static_cast<Locality*>(arg);
self->delayed_removal_timer_callback_pending_ = false;
if (error == GRPC_ERROR_NONE && !self->shutdown_ && self->weight_ == 0) {
self->locality_map_->localities_.erase(self->name_);
}
self->Unref(DEBUG_LOCATION, "Locality+timer");
}
//
// XdsLb::Locality::Helper
//
bool XdsLb::PriorityList::LocalityMap::Locality::Helper::CalledByPendingChild()
const {
GPR_ASSERT(child_ != nullptr);
return child_ == locality_->pending_child_policy_.get();
}
bool XdsLb::PriorityList::LocalityMap::Locality::Helper::CalledByCurrentChild()
const {
GPR_ASSERT(child_ != nullptr);
return child_ == locality_->child_policy_.get();
}
RefCountedPtr<SubchannelInterface>
XdsLb::PriorityList::LocalityMap::Locality::Helper::CreateSubchannel(
const grpc_channel_args& args) {
if (locality_->xds_policy()->shutting_down_ ||
(!CalledByPendingChild() && !CalledByCurrentChild())) {
return nullptr;
}
return locality_->xds_policy()->channel_control_helper()->CreateSubchannel(
args);
}
void XdsLb::PriorityList::LocalityMap::Locality::Helper::UpdateState(
grpc_connectivity_state state, UniquePtr<SubchannelPicker> picker) {
if (locality_->xds_policy()->shutting_down_) return;
// If this request is from the pending child policy, ignore it until
// it reports READY, at which point we swap it into place.
if (CalledByPendingChild()) {
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO,
"[xdslb %p helper %p] pending child policy %p reports state=%s",
locality_->xds_policy(), this,
locality_->pending_child_policy_.get(),
grpc_connectivity_state_name(state));
}
if (state != GRPC_CHANNEL_READY) return;
grpc_pollset_set_del_pollset_set(
locality_->child_policy_->interested_parties(),
locality_->xds_policy()->interested_parties());
locality_->child_policy_ = std::move(locality_->pending_child_policy_);
} else if (!CalledByCurrentChild()) {
// This request is from an outdated child, so ignore it.
return;
}
GPR_ASSERT(locality_->xds_policy()->lb_chand_ != nullptr);
// Cache the picker and its state in the locality.
locality_->picker_wrapper_ = MakeRefCounted<PickerWrapper>(
std::move(picker),
locality_->xds_policy()->client_stats_.FindLocalityStats(
locality_->name_));
locality_->connectivity_state_ = state;
// Notify the locality map.
locality_->locality_map_->OnLocalityStateUpdateLocked();
}
void XdsLb::PriorityList::LocalityMap::Locality::Helper::RequestReresolution() {
if (locality_->xds_policy()->shutting_down_) return;
// If there is a pending child policy, ignore re-resolution requests
// from the current child policy (or any outdated child).
if (locality_->pending_child_policy_ != nullptr && !CalledByPendingChild()) {
return;
}
if (GRPC_TRACE_FLAG_ENABLED(grpc_lb_xds_trace)) {
gpr_log(GPR_INFO,
"[xdslb %p] Re-resolution requested from the internal RR policy "
"(%p).",
locality_->xds_policy(), locality_->child_policy_.get());
}
GPR_ASSERT(locality_->xds_policy()->lb_chand_ != nullptr);
// If we are talking to a balancer, we expect to get updated addresses
// from the balancer, so we can ignore the re-resolution request from
// the child policy. Otherwise, pass the re-resolution request up to the
// channel.
if (locality_->xds_policy()->lb_chand_->eds_calld() == nullptr ||
!locality_->xds_policy()->lb_chand_->eds_calld()->seen_response()) {
locality_->xds_policy()->channel_control_helper()->RequestReresolution();
}
}
void XdsLb::PriorityList::LocalityMap::Locality::Helper::AddTraceEvent(
TraceSeverity severity, StringView message) {
if (locality_->xds_policy()->shutting_down_ ||
(!CalledByPendingChild() && !CalledByCurrentChild())) {
return;
}
locality_->xds_policy()->channel_control_helper()->AddTraceEvent(severity,
message);
}
//
// factory
//
class XdsFactory : public LoadBalancingPolicyFactory {
public:
OrphanablePtr<LoadBalancingPolicy> CreateLoadBalancingPolicy(
LoadBalancingPolicy::Args args) const override {
return OrphanablePtr<LoadBalancingPolicy>(New<XdsLb>(std::move(args)));
}
const char* name() const override { return kXds; }
RefCountedPtr<LoadBalancingPolicy::Config> ParseLoadBalancingConfig(
const grpc_json* json, grpc_error** error) const override {
GPR_DEBUG_ASSERT(error != nullptr && *error == GRPC_ERROR_NONE);
if (json == nullptr) {
// xds was mentioned as a policy in the deprecated loadBalancingPolicy
// field or in the client API.
*error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
"field:loadBalancingPolicy error:Xds Parser has required field - "
"balancerName. Please use loadBalancingConfig field of service "
"config instead.");
return nullptr;
}
GPR_DEBUG_ASSERT(strcmp(json->key, name()) == 0);
InlinedVector<grpc_error*, 3> error_list;
const char* balancer_name = nullptr;
RefCountedPtr<LoadBalancingPolicy::Config> child_policy;
RefCountedPtr<LoadBalancingPolicy::Config> fallback_policy;
for (const grpc_json* field = json->child; field != nullptr;
field = field->next) {
if (field->key == nullptr) continue;
if (strcmp(field->key, "balancerName") == 0) {
if (balancer_name != nullptr) {
error_list.push_back(GRPC_ERROR_CREATE_FROM_STATIC_STRING(
"field:balancerName error:Duplicate entry"));
}
if (field->type != GRPC_JSON_STRING) {
error_list.push_back(GRPC_ERROR_CREATE_FROM_STATIC_STRING(
"field:balancerName error:type should be string"));
continue;
}
balancer_name = field->value;
} else if (strcmp(field->key, "childPolicy") == 0) {
if (child_policy != nullptr) {
error_list.push_back(GRPC_ERROR_CREATE_FROM_STATIC_STRING(
"field:childPolicy error:Duplicate entry"));
}
grpc_error* parse_error = GRPC_ERROR_NONE;
child_policy = LoadBalancingPolicyRegistry::ParseLoadBalancingConfig(
field, &parse_error);
if (child_policy == nullptr) {
GPR_DEBUG_ASSERT(parse_error != GRPC_ERROR_NONE);
error_list.push_back(parse_error);
}
} else if (strcmp(field->key, "fallbackPolicy") == 0) {
if (fallback_policy != nullptr) {
error_list.push_back(GRPC_ERROR_CREATE_FROM_STATIC_STRING(
"field:fallbackPolicy error:Duplicate entry"));
}
grpc_error* parse_error = GRPC_ERROR_NONE;
fallback_policy = LoadBalancingPolicyRegistry::ParseLoadBalancingConfig(
field, &parse_error);
if (fallback_policy == nullptr) {
GPR_DEBUG_ASSERT(parse_error != GRPC_ERROR_NONE);
error_list.push_back(parse_error);
}
}
}
if (error_list.empty()) {
return RefCountedPtr<LoadBalancingPolicy::Config>(New<ParsedXdsConfig>(
balancer_name, std::move(child_policy), std::move(fallback_policy)));
} else {
*error = GRPC_ERROR_CREATE_FROM_VECTOR("Xds Parser", &error_list);
return nullptr;
}
}
};
} // namespace
} // namespace grpc_core
//
// Plugin registration
//
void grpc_lb_policy_xds_init() {
grpc_core::LoadBalancingPolicyRegistry::Builder::
RegisterLoadBalancingPolicyFactory(
grpc_core::UniquePtr<grpc_core::LoadBalancingPolicyFactory>(
grpc_core::New<grpc_core::XdsFactory>()));
}
void grpc_lb_policy_xds_shutdown() {}