Apache Kafka
=================
See our [web site](http://kafka.apache.org) for details on the project.

You need to have [Gradle](http://www.gradle.org/installation) and [Java](http://www.oracle.com/technetwork/java/javase/downloads/index.html) installed.

Kafka requires Gradle 2.0 or higher.

Java 7 should be used for building in order to support both Java 7 and Java 8 at runtime.

### First bootstrap and download the wrapper ###
    cd kafka_source_dir
    gradle

Now everything else will work.

### Building a jar and running it ###
    ./gradlew jar

Follow instructions in http://kafka.apache.org/documentation.html#quickstart

### Building source jar ###
    ./gradlew srcJar

### Building aggregated javadoc ###
    ./gradlew aggregatedJavadoc

### Building javadoc and scaladoc ###
    ./gradlew javadoc
    ./gradlew javadocJar # builds a javadoc jar for each module
    ./gradlew scaladoc
    ./gradlew scaladocJar # builds a scaladoc jar for each module
    ./gradlew docsJar # builds both (if applicable) javadoc and scaladoc jars for each module

### Running unit tests ###
    ./gradlew test

### Forcing re-running unit tests w/o code change ###
    ./gradlew cleanTest test

### Running a particular unit test ###
    ./gradlew -Dtest.single=RequestResponseSerializationTest core:test

### Running a particular test method within a unit test ###
    ./gradlew core:test --tests kafka.api.ProducerFailureHandlingTest.testCannotSendToInternalTopic
    ./gradlew clients:test --tests org.apache.kafka.clients.MetadataTest.testMetadataUpdateWaitTime

### Running a particular unit test with log4j output ###
Change the log4j setting in either `clients/src/test/resources/log4j.properties` or `core/src/test/resources/log4j.properties`

    ./gradlew -i -Dtest.single=RequestResponseSerializationTest core:test

### Generating test coverage reports ###
    ./gradlew reportCoverage

### Building a binary release gzipped tar ball ###
    ./gradlew clean
    ./gradlew releaseTarGz

The above command will fail if you haven't set up the signing key. To bypass signing the artifact, you can run:

    ./gradlew releaseTarGz -x signArchives

The release file can be found inside `./core/build/distributions/`.

### Cleaning the build ###
    ./gradlew clean

### Running a task on a particular version of Scala (either 2.10.6 or 2.11.8) ###
*Note that if building the jars with a version other than 2.10, you need to set the `SCALA_BINARY_VERSION` variable or change it in `bin/kafka-run-class.sh` to run the quick start.*

You can pass either the major version (eg 2.11) or the full version (eg 2.11.8):

    ./gradlew -PscalaVersion=2.11 jar
    ./gradlew -PscalaVersion=2.11 test
    ./gradlew -PscalaVersion=2.11 releaseTarGz

### Running a task for a specific project ###
This is for `core`, `examples` and `clients`

    ./gradlew core:jar
    ./gradlew core:test

### Listing all gradle tasks ###
    ./gradlew tasks

### Building IDE project ####
*Note that this is not strictly necessary (IntelliJ IDEA has good built-in support for Gradle projects, for example).*

    ./gradlew eclipse
    ./gradlew idea

### Building the jar for all scala versions and for all projects ###
    ./gradlew jarAll

### Running unit tests for all scala versions and for all projects ###
    ./gradlew testAll

### Building a binary release gzipped tar ball for all scala versions ###
    ./gradlew releaseTarGzAll

### Publishing the jar for all version of Scala and for all projects to maven ###
    ./gradlew uploadArchivesAll

Please note for this to work you should create/update `${GRADLE_USER_HOME}/gradle.properties` (typically, `~/.gradle/gradle.properties`) and assign the following variables

    mavenUrl=
    mavenUsername=
    mavenPassword=
    signing.keyId=
    signing.password=
    signing.secretKeyRingFile=

### Installing the jars to the local Maven repository ###
    ./gradlew installAll

### Building the test jar ###
    ./gradlew testJar

### Determining how transitive dependencies are added ###
    ./gradlew core:dependencies --configuration runtime

### Determining if any dependencies could be updated ###
    ./gradlew dependencyUpdates

### Running checkstyle on the java code ###
    ./gradlew checkstyleMain checkstyleTest

This will most commonly be useful for automated builds where the full resources of the host running the build and tests
may not be dedicated to Kafka's build.

### Common build options ###

The following options should be set with a `-D` switch, for example `./gradlew -Dorg.gradle.project.maxParallelForms=1 test`.

* `org.gradle.project.mavenUrl`: sets the URL of the maven deployment repository (`file://path/to/repo` can be used to point to a local repository).
* `org.gradle.project.maxParallelForks`: limits the maximum number of processes for each task.
* `org.gradle.project.showStandardStreams`: shows standard out and standard error of the test JVM(s) on the console.
* `org.gradle.project.skipSigning`: skips signing of artifacts.
* `org.gradle.project.testLoggingEvents`: unit test events to be logged, separated by comma. For example `./gradlew -Dorg.gradle.project.testLoggingEvents=started,passed,skipped,failed test`

### Running in Vagrant ###

See [vagrant/README.md](vagrant/README.md).

### Contribution ###

Apache Kafka is interested in building the community; we would welcome any thoughts or [patches](https://issues.apache.org/jira/browse/KAFKA). You can reach us [on the Apache mailing lists](http://kafka.apache.org/contact.html).

To contribute follow the instructions here:
 * http://kafka.apache.org/contributing.html