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What is Samza? Build Status

Apache Samza is a distributed stream processing framework. It uses Apache Kafka for messaging, and Apache Hadoop YARN to provide fault tolerance, processor isolation, security, and resource management.

Samza's key features include:

Check out Hello Samza to try Samza. Read the Background page to learn more about Samza.

Building Samza

To build Samza from a git checkout, run:

./gradlew clean build

To build Samza from a source release, it is first necessary to download the gradle wrapper script above. This bootstrapping process requires Gradle to be installed on the source machine. Gradle is available through most package managers or directly from its website. To bootstrap the wrapper, run:

gradle -b bootstrap.gradle

After the bootstrap script has completed, the regular gradlew instructions below are available.

Java Version Support

This project is built with Java 8 and can run in a Java 8 runtime enviornment. Additionally, it also supports running in a Java 11 runtime environment. If you intend to use Samza in a Java 11 runtime environment, it means you will also need to use YARN 3.3.4+ and in which case, you should also use the samza-yarn3 module (built with YARN 3.3.4) instead of the samza-yarn (built with YARN 2.10.1). There is also a samza-shell-yarn3 that depends on the samza-yarn3 module, so use that shell module if you intend on using Yarn 3.

Scala and YARN

Samza builds with Scala 2.11 or 2.12 and YARN 2.10.1, by default. Use the -PscalaSuffix switches to change Scala versions. Samza supports building Scala with 2.11 and 2.12 and provides a YARN 2 module (samze-yarn) and a YARN 3 module (samza-yarn3).

NOTE: Some modules currently do not officially support Java 11 Runtime and are still using the YARN 2.10.1 dependency:

Also, you can make use of bin/check-all.sh in order to test multiple variants of Java JDKs, Scala, and Yarn.

Testing Samza

To run all tests:

./gradlew clean test

To run a single test:

./gradlew clean :samza-test:test -Dtest.single=TestStatefulTask

To run key-value performance tests:

./gradlew samza-shell:kvPerformanceTest -PconfigPath=file://$PWD/samza-test/src/main/config/perf/kv-perf.properties

To run yarn integration tests:

./bin/integration-tests.sh <dir> yarn-integration-tests

To run standalone integration tests:

./bin/integration-tests.sh <dir> standalone-integration-tests

Running checkstyle on the java code

./gradlew checkstyleMain checkstyleTest

Job Management

To run a job (defined in a properties file):

./gradlew samza-shell:runJob -PconfigPath=/path/to/job/config.properties

To inspect a job's latest checkpoint:

./gradlew samza-shell:checkpointTool -PconfigPath=/path/to/job/config.properties

To modify a job's checkpoint (assumes that the job is not currently running), give it a file with the new offset for each partition, in the format systems.<system>.streams.<topic>.partitions.<partition>=<offset>:

./gradlew samza-shell:checkpointTool -PconfigPath=/path/to/job/config.properties \
    -PnewOffsets=file:///path/to/new/offsets.properties

Developers

To get Eclipse projects, run:

./gradlew eclipse

For IntelliJ, run:

./gradlew idea

Contribution

To start contributing on Samza please read Rules and Contributor Corner. Notice that Samza git repository does not support git pull request.

Apache Software Foundation

Apache Samza is a top level project of the Apache Software Foundation.

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