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android / platform / external / grpc-grpc / a3fe7c0c90 / . / src / core / ext / filters / client_channel / subchannel.cc
blob: 873db8ef57cdeca7b82294f9c714f7b31ab4bcc2 [file] [log] [blame]
/*
*
* Copyright 2015 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.
*
*/
#include <grpc/support/port_platform.h>
#include "src/core/ext/filters/client_channel/subchannel.h"
#include <inttypes.h>
#include <limits.h>
#include <algorithm>
#include <cstring>
#include <grpc/support/alloc.h>
#include <grpc/support/string_util.h>
#include "src/core/ext/filters/client_channel/client_channel.h"
#include "src/core/ext/filters/client_channel/health/health_check_client.h"
#include "src/core/ext/filters/client_channel/parse_address.h"
#include "src/core/ext/filters/client_channel/proxy_mapper_registry.h"
#include "src/core/ext/filters/client_channel/service_config.h"
#include "src/core/ext/filters/client_channel/subchannel_pool_interface.h"
#include "src/core/lib/backoff/backoff.h"
#include "src/core/lib/channel/channel_args.h"
#include "src/core/lib/channel/connected_channel.h"
#include "src/core/lib/debug/stats.h"
#include "src/core/lib/gpr/alloc.h"
#include "src/core/lib/gprpp/debug_location.h"
#include "src/core/lib/gprpp/manual_constructor.h"
#include "src/core/lib/gprpp/ref_counted_ptr.h"
#include "src/core/lib/gprpp/sync.h"
#include "src/core/lib/iomgr/sockaddr_utils.h"
#include "src/core/lib/profiling/timers.h"
#include "src/core/lib/slice/slice_internal.h"
#include "src/core/lib/surface/channel.h"
#include "src/core/lib/surface/channel_init.h"
#include "src/core/lib/transport/connectivity_state.h"
#include "src/core/lib/transport/error_utils.h"
#include "src/core/lib/transport/status_metadata.h"
#include "src/core/lib/uri/uri_parser.h"
// Strong and weak refs.
#define INTERNAL_REF_BITS 16
#define STRONG_REF_MASK (~(gpr_atm)((1 << INTERNAL_REF_BITS) - 1))
// Backoff parameters.
#define GRPC_SUBCHANNEL_INITIAL_CONNECT_BACKOFF_SECONDS 1
#define GRPC_SUBCHANNEL_RECONNECT_BACKOFF_MULTIPLIER 1.6
#define GRPC_SUBCHANNEL_RECONNECT_MIN_TIMEOUT_SECONDS 20
#define GRPC_SUBCHANNEL_RECONNECT_MAX_BACKOFF_SECONDS 120
#define GRPC_SUBCHANNEL_RECONNECT_JITTER 0.2
// Conversion between subchannel call and call stack.
#define SUBCHANNEL_CALL_TO_CALL_STACK(call) \
(grpc_call_stack*)((char*)(call) + GPR_ROUND_UP_TO_MAX_ALIGNMENT_SIZE( \
sizeof(SubchannelCall)))
#define CALL_STACK_TO_SUBCHANNEL_CALL(callstack) \
(SubchannelCall*)(((char*)(call_stack)) - \
GPR_ROUND_UP_TO_MAX_ALIGNMENT_SIZE( \
sizeof(SubchannelCall)))
namespace grpc_core {
//
// ConnectedSubchannel
//
ConnectedSubchannel::ConnectedSubchannel(
grpc_channel_stack* channel_stack, const grpc_channel_args* args,
RefCountedPtr<channelz::SubchannelNode> channelz_subchannel,
intptr_t socket_uuid)
: RefCounted<ConnectedSubchannel>(&grpc_trace_stream_refcount),
channel_stack_(channel_stack),
args_(grpc_channel_args_copy(args)),
channelz_subchannel_(std::move(channelz_subchannel)),
socket_uuid_(socket_uuid) {}
ConnectedSubchannel::~ConnectedSubchannel() {
grpc_channel_args_destroy(args_);
GRPC_CHANNEL_STACK_UNREF(channel_stack_, "connected_subchannel_dtor");
}
void ConnectedSubchannel::NotifyOnStateChange(
grpc_pollset_set* interested_parties, grpc_connectivity_state* state,
grpc_closure* closure) {
grpc_transport_op* op = grpc_make_transport_op(nullptr);
grpc_channel_element* elem;
op->connectivity_state = state;
op->on_connectivity_state_change = closure;
op->bind_pollset_set = interested_parties;
elem = grpc_channel_stack_element(channel_stack_, 0);
elem->filter->start_transport_op(elem, op);
}
void ConnectedSubchannel::Ping(grpc_closure* on_initiate,
grpc_closure* on_ack) {
grpc_transport_op* op = grpc_make_transport_op(nullptr);
grpc_channel_element* elem;
op->send_ping.on_initiate = on_initiate;
op->send_ping.on_ack = on_ack;
elem = grpc_channel_stack_element(channel_stack_, 0);
elem->filter->start_transport_op(elem, op);
}
RefCountedPtr<SubchannelCall> ConnectedSubchannel::CreateCall(
const CallArgs& args, grpc_error** error) {
const size_t allocation_size =
GetInitialCallSizeEstimate(args.parent_data_size);
RefCountedPtr<SubchannelCall> call(
new (args.arena->Alloc(allocation_size))
SubchannelCall(Ref(DEBUG_LOCATION, "subchannel_call"), args));
grpc_call_stack* callstk = SUBCHANNEL_CALL_TO_CALL_STACK(call.get());
const grpc_call_element_args call_args = {
callstk, /* call_stack */
nullptr, /* server_transport_data */
args.context, /* context */
args.path, /* path */
args.start_time, /* start_time */
args.deadline, /* deadline */
args.arena, /* arena */
args.call_combiner /* call_combiner */
};
*error = grpc_call_stack_init(channel_stack_, 1, SubchannelCall::Destroy,
call.get(), &call_args);
if (GPR_UNLIKELY(*error != GRPC_ERROR_NONE)) {
const char* error_string = grpc_error_string(*error);
gpr_log(GPR_ERROR, "error: %s", error_string);
return call;
}
grpc_call_stack_set_pollset_or_pollset_set(callstk, args.pollent);
if (channelz_subchannel_ != nullptr) {
channelz_subchannel_->RecordCallStarted();
}
return call;
}
size_t ConnectedSubchannel::GetInitialCallSizeEstimate(
size_t parent_data_size) const {
size_t allocation_size =
GPR_ROUND_UP_TO_MAX_ALIGNMENT_SIZE(sizeof(SubchannelCall));
if (parent_data_size > 0) {
allocation_size +=
GPR_ROUND_UP_TO_MAX_ALIGNMENT_SIZE(channel_stack_->call_stack_size) +
parent_data_size;
} else {
allocation_size += channel_stack_->call_stack_size;
}
return allocation_size;
}
//
// SubchannelCall
//
void SubchannelCall::StartTransportStreamOpBatch(
grpc_transport_stream_op_batch* batch) {
GPR_TIMER_SCOPE("subchannel_call_process_op", 0);
MaybeInterceptRecvTrailingMetadata(batch);
grpc_call_stack* call_stack = SUBCHANNEL_CALL_TO_CALL_STACK(this);
grpc_call_element* top_elem = grpc_call_stack_element(call_stack, 0);
GRPC_CALL_LOG_OP(GPR_INFO, top_elem, batch);
top_elem->filter->start_transport_stream_op_batch(top_elem, batch);
}
void* SubchannelCall::GetParentData() {
grpc_channel_stack* chanstk = connected_subchannel_->channel_stack();
return (char*)this +
GPR_ROUND_UP_TO_MAX_ALIGNMENT_SIZE(sizeof(SubchannelCall)) +
GPR_ROUND_UP_TO_MAX_ALIGNMENT_SIZE(chanstk->call_stack_size);
}
grpc_call_stack* SubchannelCall::GetCallStack() {
return SUBCHANNEL_CALL_TO_CALL_STACK(this);
}
void SubchannelCall::SetAfterCallStackDestroy(grpc_closure* closure) {
GPR_ASSERT(after_call_stack_destroy_ == nullptr);
GPR_ASSERT(closure != nullptr);
after_call_stack_destroy_ = closure;
}
RefCountedPtr<SubchannelCall> SubchannelCall::Ref() {
IncrementRefCount();
return RefCountedPtr<SubchannelCall>(this);
}
RefCountedPtr<SubchannelCall> SubchannelCall::Ref(
const grpc_core::DebugLocation& location, const char* reason) {
IncrementRefCount(location, reason);
return RefCountedPtr<SubchannelCall>(this);
}
void SubchannelCall::Unref() {
GRPC_CALL_STACK_UNREF(SUBCHANNEL_CALL_TO_CALL_STACK(this), "");
}
void SubchannelCall::Unref(const DebugLocation& location, const char* reason) {
GRPC_CALL_STACK_UNREF(SUBCHANNEL_CALL_TO_CALL_STACK(this), reason);
}
void SubchannelCall::Destroy(void* arg, grpc_error* error) {
GPR_TIMER_SCOPE("subchannel_call_destroy", 0);
SubchannelCall* self = static_cast<SubchannelCall*>(arg);
// Keep some members before destroying the subchannel call.
grpc_closure* after_call_stack_destroy = self->after_call_stack_destroy_;
RefCountedPtr<ConnectedSubchannel> connected_subchannel =
std::move(self->connected_subchannel_);
// Destroy the subchannel call.
self->~SubchannelCall();
// Destroy the call stack. This should be after destroying the subchannel
// call, because call->after_call_stack_destroy(), if not null, will free the
// call arena.
grpc_call_stack_destroy(SUBCHANNEL_CALL_TO_CALL_STACK(self), nullptr,
after_call_stack_destroy);
// Automatically reset connected_subchannel. This should be after destroying
// the call stack, because destroying call stack needs access to the channel
// stack.
}
void SubchannelCall::MaybeInterceptRecvTrailingMetadata(
grpc_transport_stream_op_batch* batch) {
// only intercept payloads with recv trailing.
if (!batch->recv_trailing_metadata) {
return;
}
// only add interceptor is channelz is enabled.
if (connected_subchannel_->channelz_subchannel() == nullptr) {
return;
}
GRPC_CLOSURE_INIT(&recv_trailing_metadata_ready_, RecvTrailingMetadataReady,
this, grpc_schedule_on_exec_ctx);
// save some state needed for the interception callback.
GPR_ASSERT(recv_trailing_metadata_ == nullptr);
recv_trailing_metadata_ =
batch->payload->recv_trailing_metadata.recv_trailing_metadata;
original_recv_trailing_metadata_ =
batch->payload->recv_trailing_metadata.recv_trailing_metadata_ready;
batch->payload->recv_trailing_metadata.recv_trailing_metadata_ready =
&recv_trailing_metadata_ready_;
}
namespace {
// Sets *status based on the rest of the parameters.
void GetCallStatus(grpc_status_code* status, grpc_millis deadline,
grpc_metadata_batch* md_batch, grpc_error* error) {
if (error != GRPC_ERROR_NONE) {
grpc_error_get_status(error, deadline, status, nullptr, nullptr, nullptr);
} else {
if (md_batch->idx.named.grpc_status != nullptr) {
*status = grpc_get_status_code_from_metadata(
md_batch->idx.named.grpc_status->md);
} else {
*status = GRPC_STATUS_UNKNOWN;
}
}
GRPC_ERROR_UNREF(error);
}
} // namespace
void SubchannelCall::RecvTrailingMetadataReady(void* arg, grpc_error* error) {
SubchannelCall* call = static_cast<SubchannelCall*>(arg);
GPR_ASSERT(call->recv_trailing_metadata_ != nullptr);
grpc_status_code status = GRPC_STATUS_OK;
GetCallStatus(&status, call->deadline_, call->recv_trailing_metadata_,
GRPC_ERROR_REF(error));
channelz::SubchannelNode* channelz_subchannel =
call->connected_subchannel_->channelz_subchannel();
GPR_ASSERT(channelz_subchannel != nullptr);
if (status == GRPC_STATUS_OK) {
channelz_subchannel->RecordCallSucceeded();
} else {
channelz_subchannel->RecordCallFailed();
}
GRPC_CLOSURE_RUN(call->original_recv_trailing_metadata_,
GRPC_ERROR_REF(error));
}
void SubchannelCall::IncrementRefCount() {
GRPC_CALL_STACK_REF(SUBCHANNEL_CALL_TO_CALL_STACK(this), "");
}
void SubchannelCall::IncrementRefCount(const grpc_core::DebugLocation& location,
const char* reason) {
GRPC_CALL_STACK_REF(SUBCHANNEL_CALL_TO_CALL_STACK(this), reason);
}
//
// Subchannel::ConnectedSubchannelStateWatcher
//
class Subchannel::ConnectedSubchannelStateWatcher
: public InternallyRefCounted<ConnectedSubchannelStateWatcher> {
public:
// Must be instantiated while holding c->mu.
explicit ConnectedSubchannelStateWatcher(Subchannel* c) : subchannel_(c) {
// Steal subchannel ref for connecting.
GRPC_SUBCHANNEL_WEAK_REF(subchannel_, "state_watcher");
GRPC_SUBCHANNEL_WEAK_UNREF(subchannel_, "connecting");
// Start watching for connectivity state changes.
// Callback uses initial ref to this.
GRPC_CLOSURE_INIT(&on_connectivity_changed_, OnConnectivityChanged, this,
grpc_schedule_on_exec_ctx);
c->connected_subchannel_->NotifyOnStateChange(c->pollset_set_,
&pending_connectivity_state_,
&on_connectivity_changed_);
// Start health check if needed.
grpc_connectivity_state health_state = GRPC_CHANNEL_READY;
if (c->health_check_service_name_ != nullptr) {
health_check_client_ = MakeOrphanable<HealthCheckClient>(
c->health_check_service_name_.get(), c->connected_subchannel_,
c->pollset_set_, c->channelz_node_);
GRPC_CLOSURE_INIT(&on_health_changed_, OnHealthChanged, this,
grpc_schedule_on_exec_ctx);
Ref().release(); // Ref for health callback tracked manually.
health_check_client_->NotifyOnHealthChange(&health_state_,
&on_health_changed_);
health_state = GRPC_CHANNEL_CONNECTING;
}
// Report initial state.
c->SetConnectivityStateLocked(GRPC_CHANNEL_READY, "subchannel_connected");
grpc_connectivity_state_set(&c->state_and_health_tracker_, health_state,
"subchannel_connected");
}
~ConnectedSubchannelStateWatcher() {
GRPC_SUBCHANNEL_WEAK_UNREF(subchannel_, "state_watcher");
}
// Must be called while holding subchannel_->mu.
void Orphan() override { health_check_client_.reset(); }
private:
static void OnConnectivityChanged(void* arg, grpc_error* error) {
auto* self = static_cast<ConnectedSubchannelStateWatcher*>(arg);
Subchannel* c = self->subchannel_;
{
MutexLock lock(&c->mu_);
switch (self->pending_connectivity_state_) {
case GRPC_CHANNEL_TRANSIENT_FAILURE:
case GRPC_CHANNEL_SHUTDOWN: {
if (!c->disconnected_ && c->connected_subchannel_ != nullptr) {
if (grpc_trace_stream_refcount.enabled()) {
gpr_log(GPR_INFO,
"Connected subchannel %p of subchannel %p has gone into "
"%s. Attempting to reconnect.",
c->connected_subchannel_.get(), c,
grpc_connectivity_state_name(
self->pending_connectivity_state_));
}
c->connected_subchannel_.reset();
c->connected_subchannel_watcher_.reset();
self->last_connectivity_state_ = GRPC_CHANNEL_TRANSIENT_FAILURE;
c->SetConnectivityStateLocked(GRPC_CHANNEL_TRANSIENT_FAILURE,
"reflect_child");
grpc_connectivity_state_set(&c->state_and_health_tracker_,
GRPC_CHANNEL_TRANSIENT_FAILURE,
"reflect_child");
c->backoff_begun_ = false;
c->backoff_.Reset();
c->MaybeStartConnectingLocked();
} else {
self->last_connectivity_state_ = GRPC_CHANNEL_SHUTDOWN;
}
self->health_check_client_.reset();
break;
}
default: {
// In principle, this should never happen. We should not get
// a callback for READY, because that was the state we started
// this watch from. And a connected subchannel should never go
// from READY to CONNECTING or IDLE.
self->last_connectivity_state_ = self->pending_connectivity_state_;
c->SetConnectivityStateLocked(self->pending_connectivity_state_,
"reflect_child");
if (self->pending_connectivity_state_ != GRPC_CHANNEL_READY) {
grpc_connectivity_state_set(&c->state_and_health_tracker_,
self->pending_connectivity_state_,
"reflect_child");
}
c->connected_subchannel_->NotifyOnStateChange(
nullptr, &self->pending_connectivity_state_,
&self->on_connectivity_changed_);
self = nullptr; // So we don't unref below.
}
}
}
// Don't unref until we've released the lock, because this might
// cause the subchannel (which contains the lock) to be destroyed.
if (self != nullptr) self->Unref();
}
static void OnHealthChanged(void* arg, grpc_error* error) {
auto* self = static_cast<ConnectedSubchannelStateWatcher*>(arg);
Subchannel* c = self->subchannel_;
{
MutexLock lock(&c->mu_);
if (self->health_state_ != GRPC_CHANNEL_SHUTDOWN &&
self->health_check_client_ != nullptr) {
if (self->last_connectivity_state_ == GRPC_CHANNEL_READY) {
grpc_connectivity_state_set(&c->state_and_health_tracker_,
self->health_state_, "health_changed");
}
self->health_check_client_->NotifyOnHealthChange(
&self->health_state_, &self->on_health_changed_);
self = nullptr; // So we don't unref below.
}
}
// Don't unref until we've released the lock, because this might
// cause the subchannel (which contains the lock) to be destroyed.
if (self != nullptr) self->Unref();
}
Subchannel* subchannel_;
grpc_closure on_connectivity_changed_;
grpc_connectivity_state pending_connectivity_state_ = GRPC_CHANNEL_READY;
grpc_connectivity_state last_connectivity_state_ = GRPC_CHANNEL_READY;
OrphanablePtr<HealthCheckClient> health_check_client_;
grpc_closure on_health_changed_;
grpc_connectivity_state health_state_ = GRPC_CHANNEL_CONNECTING;
};
//
// Subchannel::ExternalStateWatcher
//
struct Subchannel::ExternalStateWatcher {
ExternalStateWatcher(Subchannel* subchannel, grpc_pollset_set* pollset_set,
grpc_closure* notify)
: subchannel(subchannel), pollset_set(pollset_set), notify(notify) {
GRPC_SUBCHANNEL_WEAK_REF(subchannel, "external_state_watcher+init");
GRPC_CLOSURE_INIT(&on_state_changed, OnStateChanged, this,
grpc_schedule_on_exec_ctx);
}
static void OnStateChanged(void* arg, grpc_error* error) {
ExternalStateWatcher* w = static_cast<ExternalStateWatcher*>(arg);
grpc_closure* follow_up = w->notify;
if (w->pollset_set != nullptr) {
grpc_pollset_set_del_pollset_set(w->subchannel->pollset_set_,
w->pollset_set);
}
{
MutexLock lock(&w->subchannel->mu_);
if (w->subchannel->external_state_watcher_list_ == w) {
w->subchannel->external_state_watcher_list_ = w->next;
}
if (w->next != nullptr) w->next->prev = w->prev;
if (w->prev != nullptr) w->prev->next = w->next;
}
GRPC_SUBCHANNEL_WEAK_UNREF(w->subchannel, "external_state_watcher+done");
Delete(w);
GRPC_CLOSURE_SCHED(follow_up, GRPC_ERROR_REF(error));
}
Subchannel* subchannel;
grpc_pollset_set* pollset_set;
grpc_closure* notify;
grpc_closure on_state_changed;
ExternalStateWatcher* next = nullptr;
ExternalStateWatcher* prev = nullptr;
};
//
// Subchannel
//
namespace {
BackOff::Options ParseArgsForBackoffValues(
const grpc_channel_args* args, grpc_millis* min_connect_timeout_ms) {
grpc_millis initial_backoff_ms =
GRPC_SUBCHANNEL_INITIAL_CONNECT_BACKOFF_SECONDS * 1000;
*min_connect_timeout_ms =
GRPC_SUBCHANNEL_RECONNECT_MIN_TIMEOUT_SECONDS * 1000;
grpc_millis max_backoff_ms =
GRPC_SUBCHANNEL_RECONNECT_MAX_BACKOFF_SECONDS * 1000;
bool fixed_reconnect_backoff = false;
if (args != nullptr) {
for (size_t i = 0; i < args->num_args; i++) {
if (0 == strcmp(args->args[i].key,
"grpc.testing.fixed_reconnect_backoff_ms")) {
fixed_reconnect_backoff = true;
initial_backoff_ms = *min_connect_timeout_ms = max_backoff_ms =
grpc_channel_arg_get_integer(
&args->args[i],
{static_cast<int>(initial_backoff_ms), 100, INT_MAX});
} else if (0 ==
strcmp(args->args[i].key, GRPC_ARG_MIN_RECONNECT_BACKOFF_MS)) {
fixed_reconnect_backoff = false;
*min_connect_timeout_ms = grpc_channel_arg_get_integer(
&args->args[i],
{static_cast<int>(*min_connect_timeout_ms), 100, INT_MAX});
} else if (0 ==
strcmp(args->args[i].key, GRPC_ARG_MAX_RECONNECT_BACKOFF_MS)) {
fixed_reconnect_backoff = false;
max_backoff_ms = grpc_channel_arg_get_integer(
&args->args[i], {static_cast<int>(max_backoff_ms), 100, INT_MAX});
} else if (0 == strcmp(args->args[i].key,
GRPC_ARG_INITIAL_RECONNECT_BACKOFF_MS)) {
fixed_reconnect_backoff = false;
initial_backoff_ms = grpc_channel_arg_get_integer(
&args->args[i],
{static_cast<int>(initial_backoff_ms), 100, INT_MAX});
}
}
}
return BackOff::Options()
.set_initial_backoff(initial_backoff_ms)
.set_multiplier(fixed_reconnect_backoff
? 1.0
: GRPC_SUBCHANNEL_RECONNECT_BACKOFF_MULTIPLIER)
.set_jitter(fixed_reconnect_backoff ? 0.0
: GRPC_SUBCHANNEL_RECONNECT_JITTER)
.set_max_backoff(max_backoff_ms);
}
} // namespace
Subchannel::Subchannel(SubchannelKey* key, grpc_connector* connector,
const grpc_channel_args* args)
: key_(key),
connector_(connector),
backoff_(ParseArgsForBackoffValues(args, &min_connect_timeout_ms_)) {
GRPC_STATS_INC_CLIENT_SUBCHANNELS_CREATED();
gpr_atm_no_barrier_store(&ref_pair_, 1 << INTERNAL_REF_BITS);
grpc_connector_ref(connector_);
pollset_set_ = grpc_pollset_set_create();
grpc_resolved_address* addr =
static_cast<grpc_resolved_address*>(gpr_malloc(sizeof(*addr)));
GetAddressFromSubchannelAddressArg(args, addr);
grpc_resolved_address* new_address = nullptr;
grpc_channel_args* new_args = nullptr;
if (grpc_proxy_mappers_map_address(addr, args, &new_address, &new_args)) {
GPR_ASSERT(new_address != nullptr);
gpr_free(addr);
addr = new_address;
}
static const char* keys_to_remove[] = {GRPC_ARG_SUBCHANNEL_ADDRESS};
grpc_arg new_arg = CreateSubchannelAddressArg(addr);
gpr_free(addr);
args_ = grpc_channel_args_copy_and_add_and_remove(
new_args != nullptr ? new_args : args, keys_to_remove,
GPR_ARRAY_SIZE(keys_to_remove), &new_arg, 1);
gpr_free(new_arg.value.string);
if (new_args != nullptr) grpc_channel_args_destroy(new_args);
GRPC_CLOSURE_INIT(&on_connecting_finished_, OnConnectingFinished, this,
grpc_schedule_on_exec_ctx);
grpc_connectivity_state_init(&state_tracker_, GRPC_CHANNEL_IDLE,
"subchannel");
grpc_connectivity_state_init(&state_and_health_tracker_, GRPC_CHANNEL_IDLE,
"subchannel");
health_check_service_name_ =
UniquePtr<char>(gpr_strdup(grpc_channel_arg_get_string(
grpc_channel_args_find(args_, "grpc.temp.health_check"))));
const grpc_arg* arg = grpc_channel_args_find(args_, GRPC_ARG_ENABLE_CHANNELZ);
const bool channelz_enabled =
grpc_channel_arg_get_bool(arg, GRPC_ENABLE_CHANNELZ_DEFAULT);
arg = grpc_channel_args_find(
args_, GRPC_ARG_MAX_CHANNEL_TRACE_EVENT_MEMORY_PER_NODE);
const grpc_integer_options options = {
GRPC_MAX_CHANNEL_TRACE_EVENT_MEMORY_PER_NODE_DEFAULT, 0, INT_MAX};
size_t channel_tracer_max_memory =
(size_t)grpc_channel_arg_get_integer(arg, options);
if (channelz_enabled) {
channelz_node_ = MakeRefCounted<channelz::SubchannelNode>(
this, channel_tracer_max_memory);
channelz_node_->AddTraceEvent(
channelz::ChannelTrace::Severity::Info,
grpc_slice_from_static_string("subchannel created"));
}
}
Subchannel::~Subchannel() {
if (channelz_node_ != nullptr) {
channelz_node_->AddTraceEvent(
channelz::ChannelTrace::Severity::Info,
grpc_slice_from_static_string("Subchannel destroyed"));
channelz_node_->MarkSubchannelDestroyed();
}
grpc_channel_args_destroy(args_);
grpc_connectivity_state_destroy(&state_tracker_);
grpc_connectivity_state_destroy(&state_and_health_tracker_);
grpc_connector_unref(connector_);
grpc_pollset_set_destroy(pollset_set_);
Delete(key_);
}
Subchannel* Subchannel::Create(grpc_connector* connector,
const grpc_channel_args* args) {
SubchannelKey* key = New<SubchannelKey>(args);
SubchannelPoolInterface* subchannel_pool =
SubchannelPoolInterface::GetSubchannelPoolFromChannelArgs(args);
GPR_ASSERT(subchannel_pool != nullptr);
Subchannel* c = subchannel_pool->FindSubchannel(key);
if (c != nullptr) {
Delete(key);
return c;
}
c = New<Subchannel>(key, connector, args);
// Try to register the subchannel before setting the subchannel pool.
// Otherwise, in case of a registration race, unreffing c in
// RegisterSubchannel() will cause c to be tried to be unregistered, while
// its key maps to a different subchannel.
Subchannel* registered = subchannel_pool->RegisterSubchannel(key, c);
if (registered == c) c->subchannel_pool_ = subchannel_pool->Ref();
return registered;
}
Subchannel* Subchannel::Ref(GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
gpr_atm old_refs;
old_refs = RefMutate((1 << INTERNAL_REF_BITS),
0 GRPC_SUBCHANNEL_REF_MUTATE_PURPOSE("STRONG_REF"));
GPR_ASSERT((old_refs & STRONG_REF_MASK) != 0);
return this;
}
void Subchannel::Unref(GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
gpr_atm old_refs;
// add a weak ref and subtract a strong ref (atomically)
old_refs = RefMutate(
static_cast<gpr_atm>(1) - static_cast<gpr_atm>(1 << INTERNAL_REF_BITS),
1 GRPC_SUBCHANNEL_REF_MUTATE_PURPOSE("STRONG_UNREF"));
if ((old_refs & STRONG_REF_MASK) == (1 << INTERNAL_REF_BITS)) {
Disconnect();
}
GRPC_SUBCHANNEL_WEAK_UNREF(this, "strong-unref");
}
Subchannel* Subchannel::WeakRef(GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
gpr_atm old_refs;
old_refs = RefMutate(1, 0 GRPC_SUBCHANNEL_REF_MUTATE_PURPOSE("WEAK_REF"));
GPR_ASSERT(old_refs != 0);
return this;
}
namespace {
void subchannel_destroy(void* arg, grpc_error* error) {
Subchannel* self = static_cast<Subchannel*>(arg);
Delete(self);
}
} // namespace
void Subchannel::WeakUnref(GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
gpr_atm old_refs;
old_refs = RefMutate(-static_cast<gpr_atm>(1),
1 GRPC_SUBCHANNEL_REF_MUTATE_PURPOSE("WEAK_UNREF"));
if (old_refs == 1) {
GRPC_CLOSURE_SCHED(GRPC_CLOSURE_CREATE(subchannel_destroy, this,
grpc_schedule_on_exec_ctx),
GRPC_ERROR_NONE);
}
}
Subchannel* Subchannel::RefFromWeakRef(GRPC_SUBCHANNEL_REF_EXTRA_ARGS) {
for (;;) {
gpr_atm old_refs = gpr_atm_acq_load(&ref_pair_);
if (old_refs >= (1 << INTERNAL_REF_BITS)) {
gpr_atm new_refs = old_refs + (1 << INTERNAL_REF_BITS);
if (gpr_atm_rel_cas(&ref_pair_, old_refs, new_refs)) {
return this;
}
} else {
return nullptr;
}
}
}
intptr_t Subchannel::GetChildSocketUuid() {
if (connected_subchannel_ != nullptr) {
return connected_subchannel_->socket_uuid();
} else {
return 0;
}
}
const char* Subchannel::GetTargetAddress() {
const grpc_arg* addr_arg =
grpc_channel_args_find(args_, GRPC_ARG_SUBCHANNEL_ADDRESS);
const char* addr_str = grpc_channel_arg_get_string(addr_arg);
GPR_ASSERT(addr_str != nullptr); // Should have been set by LB policy.
return addr_str;
}
RefCountedPtr<ConnectedSubchannel> Subchannel::connected_subchannel() {
MutexLock lock(&mu_);
return connected_subchannel_;
}
channelz::SubchannelNode* Subchannel::channelz_node() {
return channelz_node_.get();
}
grpc_connectivity_state Subchannel::CheckConnectivity(
bool inhibit_health_checking) {
grpc_connectivity_state_tracker* tracker =
inhibit_health_checking ? &state_tracker_ : &state_and_health_tracker_;
grpc_connectivity_state state = grpc_connectivity_state_check(tracker);
return state;
}
void Subchannel::NotifyOnStateChange(grpc_pollset_set* interested_parties,
grpc_connectivity_state* state,
grpc_closure* notify,
bool inhibit_health_checking) {
grpc_connectivity_state_tracker* tracker =
inhibit_health_checking ? &state_tracker_ : &state_and_health_tracker_;
ExternalStateWatcher* w;
if (state == nullptr) {
MutexLock lock(&mu_);
for (w = external_state_watcher_list_; w != nullptr; w = w->next) {
if (w->notify == notify) {
grpc_connectivity_state_notify_on_state_change(tracker, nullptr,
&w->on_state_changed);
}
}
} else {
w = New<ExternalStateWatcher>(this, interested_parties, notify);
if (interested_parties != nullptr) {
grpc_pollset_set_add_pollset_set(pollset_set_, interested_parties);
}
MutexLock lock(&mu_);
if (external_state_watcher_list_ != nullptr) {
w->next = external_state_watcher_list_;
w->next->prev = w;
}
external_state_watcher_list_ = w;
grpc_connectivity_state_notify_on_state_change(tracker, state,
&w->on_state_changed);
MaybeStartConnectingLocked();
}
}
void Subchannel::ResetBackoff() {
MutexLock lock(&mu_);
backoff_.Reset();
if (have_retry_alarm_) {
retry_immediately_ = true;
grpc_timer_cancel(&retry_alarm_);
} else {
backoff_begun_ = false;
MaybeStartConnectingLocked();
}
}
grpc_arg Subchannel::CreateSubchannelAddressArg(
const grpc_resolved_address* addr) {
return grpc_channel_arg_string_create(
(char*)GRPC_ARG_SUBCHANNEL_ADDRESS,
addr->len > 0 ? grpc_sockaddr_to_uri(addr) : gpr_strdup(""));
}
const char* Subchannel::GetUriFromSubchannelAddressArg(
const grpc_channel_args* args) {
const grpc_arg* addr_arg =
grpc_channel_args_find(args, GRPC_ARG_SUBCHANNEL_ADDRESS);
const char* addr_str = grpc_channel_arg_get_string(addr_arg);
GPR_ASSERT(addr_str != nullptr); // Should have been set by LB policy.
return addr_str;
}
namespace {
void UriToSockaddr(const char* uri_str, grpc_resolved_address* addr) {
grpc_uri* uri = grpc_uri_parse(uri_str, 0 /* suppress_errors */);
GPR_ASSERT(uri != nullptr);
if (!grpc_parse_uri(uri, addr)) memset(addr, 0, sizeof(*addr));
grpc_uri_destroy(uri);
}
} // namespace
void Subchannel::GetAddressFromSubchannelAddressArg(
const grpc_channel_args* args, grpc_resolved_address* addr) {
const char* addr_uri_str = GetUriFromSubchannelAddressArg(args);
memset(addr, 0, sizeof(*addr));
if (*addr_uri_str != '\0') {
UriToSockaddr(addr_uri_str, addr);
}
}
namespace {
// Returns a string indicating the subchannel's connectivity state change to
// \a state.
const char* SubchannelConnectivityStateChangeString(
grpc_connectivity_state state) {
switch (state) {
case GRPC_CHANNEL_IDLE:
return "Subchannel state change to IDLE";
case GRPC_CHANNEL_CONNECTING:
return "Subchannel state change to CONNECTING";
case GRPC_CHANNEL_READY:
return "Subchannel state change to READY";
case GRPC_CHANNEL_TRANSIENT_FAILURE:
return "Subchannel state change to TRANSIENT_FAILURE";
case GRPC_CHANNEL_SHUTDOWN:
return "Subchannel state change to SHUTDOWN";
}
GPR_UNREACHABLE_CODE(return "UNKNOWN");
}
} // namespace
void Subchannel::SetConnectivityStateLocked(grpc_connectivity_state state,
const char* reason) {
if (channelz_node_ != nullptr) {
channelz_node_->AddTraceEvent(
channelz::ChannelTrace::Severity::Info,
grpc_slice_from_static_string(
SubchannelConnectivityStateChangeString(state)));
}
grpc_connectivity_state_set(&state_tracker_, state, reason);
}
void Subchannel::MaybeStartConnectingLocked() {
if (disconnected_) {
// Don't try to connect if we're already disconnected.
return;
}
if (connecting_) {
// Already connecting: don't restart.
return;
}
if (connected_subchannel_ != nullptr) {
// Already connected: don't restart.
return;
}
if (!grpc_connectivity_state_has_watchers(&state_tracker_) &&
!grpc_connectivity_state_has_watchers(&state_and_health_tracker_)) {
// Nobody is interested in connecting: so don't just yet.
return;
}
connecting_ = true;
GRPC_SUBCHANNEL_WEAK_REF(this, "connecting");
if (!backoff_begun_) {
backoff_begun_ = true;
ContinueConnectingLocked();
} else {
GPR_ASSERT(!have_retry_alarm_);
have_retry_alarm_ = true;
const grpc_millis time_til_next =
next_attempt_deadline_ - ExecCtx::Get()->Now();
if (time_til_next <= 0) {
gpr_log(GPR_INFO, "Subchannel %p: Retry immediately", this);
} else {
gpr_log(GPR_INFO, "Subchannel %p: Retry in %" PRId64 " milliseconds",
this, time_til_next);
}
GRPC_CLOSURE_INIT(&on_retry_alarm_, OnRetryAlarm, this,
grpc_schedule_on_exec_ctx);
grpc_timer_init(&retry_alarm_, next_attempt_deadline_, &on_retry_alarm_);
}
}
void Subchannel::OnRetryAlarm(void* arg, grpc_error* error) {
Subchannel* c = static_cast<Subchannel*>(arg);
// TODO(soheilhy): Once subchannel refcounting is simplified, we can get use
// MutexLock instead of ReleasableMutexLock, here.
ReleasableMutexLock lock(&c->mu_);
c->have_retry_alarm_ = false;
if (c->disconnected_) {
error = GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING("Disconnected",
&error, 1);
} else if (c->retry_immediately_) {
c->retry_immediately_ = false;
error = GRPC_ERROR_NONE;
} else {
GRPC_ERROR_REF(error);
}
if (error == GRPC_ERROR_NONE) {
gpr_log(GPR_INFO, "Failed to connect to channel, retrying");
c->ContinueConnectingLocked();
lock.Unlock();
} else {
lock.Unlock();
GRPC_SUBCHANNEL_WEAK_UNREF(c, "connecting");
}
GRPC_ERROR_UNREF(error);
}
void Subchannel::ContinueConnectingLocked() {
grpc_connect_in_args args;
args.interested_parties = pollset_set_;
const grpc_millis min_deadline =
min_connect_timeout_ms_ + ExecCtx::Get()->Now();
next_attempt_deadline_ = backoff_.NextAttemptTime();
args.deadline = std::max(next_attempt_deadline_, min_deadline);
args.channel_args = args_;
SetConnectivityStateLocked(GRPC_CHANNEL_CONNECTING, "connecting");
grpc_connectivity_state_set(&state_and_health_tracker_,
GRPC_CHANNEL_CONNECTING, "connecting");
grpc_connector_connect(connector_, &args, &connecting_result_,
&on_connecting_finished_);
}
void Subchannel::OnConnectingFinished(void* arg, grpc_error* error) {
auto* c = static_cast<Subchannel*>(arg);
grpc_channel_args* delete_channel_args = c->connecting_result_.channel_args;
GRPC_SUBCHANNEL_WEAK_REF(c, "on_connecting_finished");
{
MutexLock lock(&c->mu_);
c->connecting_ = false;
if (c->connecting_result_.transport != nullptr &&
c->PublishTransportLocked()) {
// Do nothing, transport was published.
} else if (c->disconnected_) {
GRPC_SUBCHANNEL_WEAK_UNREF(c, "connecting");
} else {
gpr_log(GPR_INFO, "Connect failed: %s", grpc_error_string(error));
c->SetConnectivityStateLocked(GRPC_CHANNEL_TRANSIENT_FAILURE,
"connect_failed");
grpc_connectivity_state_set(&c->state_and_health_tracker_,
GRPC_CHANNEL_TRANSIENT_FAILURE,
"connect_failed");
c->MaybeStartConnectingLocked();
GRPC_SUBCHANNEL_WEAK_UNREF(c, "connecting");
}
}
GRPC_SUBCHANNEL_WEAK_UNREF(c, "on_connecting_finished");
grpc_channel_args_destroy(delete_channel_args);
}
namespace {
void ConnectionDestroy(void* arg, grpc_error* error) {
grpc_channel_stack* stk = static_cast<grpc_channel_stack*>(arg);
grpc_channel_stack_destroy(stk);
gpr_free(stk);
}
} // namespace
bool Subchannel::PublishTransportLocked() {
// Construct channel stack.
grpc_channel_stack_builder* builder = grpc_channel_stack_builder_create();
grpc_channel_stack_builder_set_channel_arguments(
builder, connecting_result_.channel_args);
grpc_channel_stack_builder_set_transport(builder,
connecting_result_.transport);
if (!grpc_channel_init_create_stack(builder, GRPC_CLIENT_SUBCHANNEL)) {
grpc_channel_stack_builder_destroy(builder);
return false;
}
grpc_channel_stack* stk;
grpc_error* error = grpc_channel_stack_builder_finish(
builder, 0, 1, ConnectionDestroy, nullptr,
reinterpret_cast<void**>(&stk));
if (error != GRPC_ERROR_NONE) {
grpc_transport_destroy(connecting_result_.transport);
gpr_log(GPR_ERROR, "error initializing subchannel stack: %s",
grpc_error_string(error));
GRPC_ERROR_UNREF(error);
return false;
}
intptr_t socket_uuid = connecting_result_.socket_uuid;
memset(&connecting_result_, 0, sizeof(connecting_result_));
if (disconnected_) {
grpc_channel_stack_destroy(stk);
gpr_free(stk);
return false;
}
// Publish.
connected_subchannel_.reset(
New<ConnectedSubchannel>(stk, args_, channelz_node_, socket_uuid));
gpr_log(GPR_INFO, "New connected subchannel at %p for subchannel %p",
connected_subchannel_.get(), this);
// Instantiate state watcher. Will clean itself up.
connected_subchannel_watcher_ =
MakeOrphanable<ConnectedSubchannelStateWatcher>(this);
return true;
}
void Subchannel::Disconnect() {
// The subchannel_pool is only used once here in this subchannel, so the
// access can be outside of the lock.
if (subchannel_pool_ != nullptr) {
subchannel_pool_->UnregisterSubchannel(key_);
subchannel_pool_.reset();
}
MutexLock lock(&mu_);
GPR_ASSERT(!disconnected_);
disconnected_ = true;
grpc_connector_shutdown(connector_, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
"Subchannel disconnected"));
connected_subchannel_.reset();
connected_subchannel_watcher_.reset();
}
gpr_atm Subchannel::RefMutate(
gpr_atm delta, int barrier GRPC_SUBCHANNEL_REF_MUTATE_EXTRA_ARGS) {
gpr_atm old_val = barrier ? gpr_atm_full_fetch_add(&ref_pair_, delta)
: gpr_atm_no_barrier_fetch_add(&ref_pair_, delta);
#ifndef NDEBUG
if (grpc_trace_stream_refcount.enabled()) {
gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
"SUBCHANNEL: %p %12s 0x%" PRIxPTR " -> 0x%" PRIxPTR " [%s]", this,
purpose, old_val, old_val + delta, reason);
}
#endif
return old_val;
}
} // namespace grpc_core