WARNING: Kythe is alpha. Use at your own risk.

Kythe is a pluggable, (mostly) language-agnostic ecosystem for building tools that work with code. This release contains the core set of indexers, extractors, and tools directly supported by the Kythe team.

License: Apache Licence, Version 2.0

Contents

• indexers
  • cxx_indexer :: C++ indexer
  • java_indexer.jar :: Java indexer
• extractors
  • bazel_cxx_extractor :: C++ extractor for Bazel extra_actions
  • bazel_java_extractor.jar :: Java extractor for Bazel extra_actions
  • cxx_extractor :: C++ extractor
  • javac_extractor.jar :: Java extractor
  • javac-wrapper.sh :: javac wrapper script for extractor
• proto :: Protocol buffer definitions of public APIs
• tools
  • dedup_stream :: Removes duplicates entries from a delimited stream
  • directory_indexer :: Emits Kythe file nodes for some local paths
  • entrystream :: Generic Kythe entry stream processor
  • http_server :: HTTP/GRPC server for Kythe service APIs (xrefs, filetree, search)
  • indexpack :: Converts between .kindex archives and indexpacks
  • kwazthis :: Determine what Kythe node(s) are at a particular point in a file
  • kythe :: CLI for the service APIs exposed by http_server
  • read_entries :: Dumps a GraphStore's contents as an entry stream
  • triples :: Converts an entry stream (or GraphStore) to N-Triples
  • verifier :: Verifies indexer outputs with source-inlined goals
  • viewindex :: Dumps a .kindex file as JSON
  • write_entries :: Writes an entry stream to a GraphStore
  • write_tables :: Processes a GraphStore into efficient serving tables for http_server

Dependencies

• Java JDK >=8
• libncurses
• libuuid

Debian Jessie Install

echo "deb http://http.debian.net/debian jessie-backports main" >> /etc/apt/sources.list
apt-get install openjdk-8-jdk libncurses5 libssl1.0.0

End-to-end Java Example

# Install Kythe
tar xzf kythe-v*.tar.gz
rm -rf /opt/kythe
mv kythe-v*/ /opt/kythe

git clone https://github.com/GoogleCloudPlatform/DataflowJavaSDK.git
cd DataflowJavaSDK

# Setup the Java extractor's environment
export REAL_JAVAC="$(which javac)"
export JAVAC_EXTRACTOR_JAR=/opt/kythe/extractors/javac_extractor.jar
export KYTHE_ROOT_DIRECTORY="$PWD"
export KYTHE_OUTPUT_DIRECTORY="/tmp/kythe"
export KYTHE_CORPUS=DataflowJavaSDK
mkdir -p "$KYTHE_OUTPUT_DIRECTORY"

# Force Maven to compile with extractors/javac-wrapper.sh
mvn clean compile \
  -Dmaven.compiler.forceJavacCompilerUse=true \
  -Dmaven.compiler.fork=true \
  -Dmaven.compiler.executable=/opt/kythe/extractors/javac-wrapper.sh

cd ..

# Index the resulting .kindex files, deduplicate the entries, and finally store
# them in a GraphStore
GRAPHSTORE=/tmp/kythe_graphstore
rm -rf "$GRAPHSTORE"
find "$KYTHE_OUTPUT_DIRECTORY" -name '*.kindex' | \
  xargs -L1 java -jar /opt/kythe/indexers/java_indexer.jar | \
  /opt/kythe/tools/dedup_stream | \
  /opt/kythe/tools/write_entries --graphstore $GRAPHSTORE

# Process the GraphStore into serving tables
SERVING=/tmp/kythe_serving
rm -rf "$SERVING"
/opt/kythe/tools/write_tables --graphstore $GRAPHSTORE --out "$SERVING"

# Launch Kythe's service APIs as an HTTP server listening to only local
# connections on port 9898.  Using `--listen :9898` instead will allow
# connections from other networked machines.
/opt/kythe/tools/http_server --serving_table "$SERVING" \
  --public_resources /opt/kythe/web/ui --listen localhost:9898

# The sample web UI will be serving at http://localhost:9898

# /opt/kythe/tools/kythe and /opt/kythe/tools/kwazthis can be used with the
# local running server by passing the '--api=http://localhost:9898' flag.

Usage

Extractors

extractors/cxx_extractor and extractors/javac_extractor.jar are flag-compatible replacements for clang and javac, respectively. Instead of performing a full compilation, they extract the compilation's full context including all file inputs and archive them in a .kindex file.

Since each extractor is meant to replace a compiler, all configuration is passed by the following environment variables:

KYTHE_ROOT_DIRECTORY (required): root directory of the repository being compiled.
    This helps the extractor correctly infer file input paths.
KYTHE_OUTPUT_DIRECTORY (required): output directory for resulting .kindex
    files
KYTHE_VNAMES: path to a JSON-encoded VNames configuration file.  See
    https://godoc.org/github.com/google/kythe/kythe/go/storage/vnameutil for
    more details on the file's format and
    https://kythe.io/repo/kythe/data/vnames.json for an example.
KYTHE_CORPUS: the name of the corpus for all constructed VNames (only used if
    KYTHE_VNAMES is unset; defaults to "kythe")

extractors/javac-wrapper.sh is provided as one way to inject an extractor into a build system -- by wrapping each compiler command. For instance, Maven compilations can easily be extracted by replacing $JAVA_HOME/bin/javac with this script and setting the following Maven options:

-Dmaven.compiler.forceJavacCompilerUse=true
-Dmaven.compiler.fork=true
-Dmaven.compiler.executable=$JAVA_HOME/bin/javac

Read extractors/javac-wrapper.sh for more details on its usage and see examples usages in the Docker images defined at https://kythe.io/repo/kythe/java/com/google/devtools/kythe/extractors/java/standalone/Dockerfile and https://kythe.io/repo/kythe/java/com/google/devtools/kythe/extractors/java/maven/Dockerfile.

Examples:

export KYTHE_ROOT_DIRECTORY="$PWD"
export KYTHE_OUTPUT_DIRECTORY=/tmp/kythe

mkdir -p "$KYTHE_OUTPUT_DIRECTORY"

java -Xbootclasspath/p:extractors/javac_extractor.jar \
  -jar extractors/javac_extractor.jar \
  -cp "${$(find third_party -name '*.jar' -printf '%p:')%:}" \
  $(find src/main -name '*.java')

extractors/cxx_extractor -Ithird_party/include some.cc

Indexers

indexers/cxx_indexer and indexers/java_indexer.jar analyze the .kindex files produced by the extractors and emit a stream of protobuf wire-encoded facts (entries) that conform to https://kythe.io/schema. The output stream can be processed by many of the accompanying binaries in the tools/ directory.

Examples

java -jar indexers/java_indexer.jar \
  /tmp/kythe/065c7a9a0789d09b73d74b0ca17cfcec6643d69a6218d095d19a770b10dffdf9.kindex \
  > java.entries

indexers/cxx_indexers \
  /tmp/kythe/579d266e5914257a9bd4458eb9b218690280ae15123d642025f224d10f64e6f3.kindex \
  > cxx.entries