Apache Beam Runners
Overview
Runners execute Beam pipelines on distributed processing backends. Each runner translates the portable Beam model to its native execution engine.
Available Runners
| Runner | Location | Description |
|---|---|---|
| Direct | runners/direct-java/ | Local execution for testing |
| Prism | runners/prism/ | Portable local runner |
| Dataflow | runners/google-cloud-dataflow-java/ | Google Cloud Dataflow |
| Flink | runners/flink/ | Apache Flink |
| Spark | runners/spark/ | Apache Spark |
| Samza | runners/samza/ | Apache Samza |
| Jet | runners/jet/ | Hazelcast Jet |
| Twister2 | runners/twister2/ | Twister2 |
Direct Runner
For local development and testing.
Java
PipelineOptions options = PipelineOptionsFactory.create();
options.setRunner(DirectRunner.class);
Pipeline p = Pipeline.create(options);Python
options = PipelineOptions()
options.view_as(StandardOptions).runner = 'DirectRunner'
p = beam.Pipeline(options=options)Command Line
--runner=DirectRunnerDataflow Runner
Prerequisites
- GCP project with Dataflow API enabled
- Service account with Dataflow Admin role
- GCS bucket for staging
Java Usage
DataflowPipelineOptions options = PipelineOptionsFactory.as(DataflowPipelineOptions.class);
options.setRunner(DataflowRunner.class);
options.setProject("my-project");
options.setRegion("us-central1");
options.setTempLocation("gs://my-bucket/temp");Python Usage
options = PipelineOptions([
'--runner=DataflowRunner',
'--project=my-project',
'--region=us-central1',
'--temp_location=gs://my-bucket/temp'
])Runner v2
--experiments=use_runner_v2Custom SDK Container
--sdkContainerImage=gcr.io/project/beam_java11_sdk:customFlink Runner
Embedded Mode
FlinkPipelineOptions options = PipelineOptionsFactory.as(FlinkPipelineOptions.class);
options.setRunner(FlinkRunner.class);
options.setFlinkMaster("[local]");Cluster Mode
options.setFlinkMaster("host:port");Portable Mode (Python)
options = PipelineOptions([
'--runner=FlinkRunner',
'--flink_master=host:port',
'--environment_type=LOOPBACK' # or DOCKER, EXTERNAL
])Spark Runner
Java
SparkPipelineOptions options = PipelineOptionsFactory.as(SparkPipelineOptions.class);
options.setRunner(SparkRunner.class);
options.setSparkMaster("local[*]"); # or spark://host:portPython (Portable)
options = PipelineOptions([
'--runner=SparkRunner',
'--spark_master_url=local[*]'
])Testing with Runners
ValidatesRunner Tests
Tests that validate runner correctness:
# Direct Runner
./gradlew :runners:direct-java:validatesRunner
# Flink Runner
./gradlew :runners:flink:1.18:validatesRunner
# Spark Runner
./gradlew :runners:spark:3:validatesRunner
# Dataflow Runner
./gradlew :runners:google-cloud-dataflow-java:validatesRunnerTestPipeline with Runners
@Rule public TestPipeline pipeline = TestPipeline.create();
// Set runner via system property
-DbeamTestPipelineOptions='["--runner=TestDataflowRunner"]'Portable Runners
Concept
- SDK-independent execution via Fn API
- SDK runs in container, communicates via gRPC
Environment Types
DOCKER- SDK in Docker containerLOOPBACK- SDK in same process (testing)EXTERNAL- SDK at specified addressPROCESS- SDK in subprocess
Job Server
Start Flink job server:
./gradlew :runners:flink:1.18:job-server:runShadowStart Spark job server:
./gradlew :runners:spark:3:job-server:runShadowRunner-Specific Options
Dataflow
| Option | Description |
|---|---|
--project | GCP project |
--region | GCP region |
--tempLocation | GCS temp location |
--stagingLocation | GCS staging |
--numWorkers | Initial workers |
--maxNumWorkers | Max workers |
--workerMachineType | VM type |
Flink
| Option | Description |
|---|---|
--flinkMaster | Flink master address |
--parallelism | Default parallelism |
--checkpointingInterval | Checkpoint interval |
Spark
| Option | Description |
|---|---|
--sparkMaster | Spark master URL |
--sparkConf | Additional Spark config |
Building Runner Artifacts
Dataflow Worker Jar
./gradlew :runners:google-cloud-dataflow-java:worker:shadowJarFlink Job Server
./gradlew :runners:flink:1.18:job-server:shadowJarSpark Job Server
./gradlew :runners:spark:3:job-server:shadowJarDebugging
Direct Runner
- Enable logging:
-Dorg.slf4j.simpleLogger.defaultLogLevel=debug - Use
--targetParallelism=1for deterministic execution
Dataflow
- Check Dataflow UI: console.cloud.google.com/dataflow
- Use
--experiments=upload_graphfor graph debugging - Worker logs in Cloud Logging
Portable Runners
- Enable debug logging on job server
- Check SDK harness logs in worker containers