Connecting to Kinesis

You can configure your Samza jobs to process data from AWS Kinesis, Amazon’s data streaming service. A Kinesis data stream is similar to a Kafka topic and can have multiple partitions. Each message consumed from a Kinesis data stream is an instance of Record.

Consuming from Kinesis:

Samza’s KinesisSystemConsumer wraps the Record into a KinesisIncomingMessageEnvelope. The key of the message is set to partition key of the Record. The message is obtained from the Record body.

To configure Samza to consume from Kinesis streams:

# define a kinesis system factory with your identifier. eg: kinesis-system
systems.kinesis-system.samza.factory=org.apache.samza.system.eventhub.KinesisSystemFactory

# kinesis system consumer works with only AllSspToSingleTaskGrouperFactory
job.systemstreampartition.grouper.factory=org.apache.samza.container.grouper.stream.AllSspToSingleTaskGrouperFactory

# define your streams
task.inputs=kinesis-system.input0

# define required properties for your streams
systems.kinesis-system.streams.input0.aws.region=YOUR-STREAM-REGION
systems.kinesis-system.streams.input0.aws.accessKey=YOUR-ACCESS_KEY
sensitive.systems.kinesis-system.streams.input0.aws.secretKey=YOUR-SECRET-KEY

The tuple required to access the Kinesis data stream must be provided, namely the fields YOUR-STREAM-REGION, YOUR-ACCESS-KEY, YOUR-SECRET-KEY.

Advanced Configuration:

AWS Client Configs:

You can configure any AWS client config with the prefix system.system-name.aws.clientConfig.*

system.system-name.aws.clientConfig.CONFIG-NAME=CONFIG-VALUE

As an example, to set a proxy host and proxy port for the AWS Client:

systems.system-name.aws.clientConfig.ProxyHost=my-proxy-host.com
systems.system-name.aws.clientConfig.ProxyPort=my-proxy-port

KCL Configs:

Similarly, you can set any Kinesis Client Library config for a stream by configuring it under systems.system-name.streams.stream-name.aws.kcl.*

systems.system-name.streams.stream-name.aws.kcl.CONFIG-NAME=CONFIG-VALUE

As an example, to reset the checkpoint and set the starting position for a stream:

systems.kinesis-system.streams.input0.aws.kcl.TableName=my-app-table-name
# set the starting position to either TRIM_HORIZON (oldest) or LATEST (latest)
systems.kinesis-system.streams.input0.aws.kcl.InitialPositionInStream=my-start-position

Limitations

The following limitations apply for Samza jobs consuming from Kinesis streams using the Samza consumer: * Stateful processing (eg: windows or joins) is not supported on Kinesis streams. However, you can accomplish this by chaining two Samza jobs where the first job reads from Kinesis and sends to Kafka while the second job processes the data from Kafka. * Kinesis streams cannot be configured as bootstrap or broadcast streams. * Kinesis streams must be used with the AllSspToSingleTaskGrouperFactory. No other grouper is supported. * A Samza job that consumes from Kinesis cannot consume from any other input source. However, you can send your results to any destination (eg: Kafka, EventHubs), and have another Samza job consume them.

Producing to Kinesis:

The KinesisSystemProducer for Samza is not yet implemented.

How to configure Samza job to consume from Kinesis data stream ?

This tutorial uses hello samza to illustrate running a Samza job on Yarn that consumes from Kinesis. We will use the KinesisHelloSamza example.

Update properties file

Update the following properties in the kinesis-hello-samza.properties file:

task.inputs=kinesis.<kinesis-stream>
systems.kinesis.streams.<kinesis-stream>.aws.region=<kinesis-stream-region>
systems.kinesis.streams.<kinesis-stream>.aws.accessKey=<your-access-key>
sensitive.systems.kinesis.streams.<kinesis-stream>.aws.region=<your-secret-key>

Now, you are ready to run your Samza application on Yarn as described here. Check the log file for messages read from your Kinesis stream.