Chapter 39. Flink Since Camel 2.18 Only producer is supported This documentation page covers the Flink component for the Apache Camel. The camel-flink component provides a bridge between Camel components and Flink tasks. This component provides a way to route a message from various transports, dynamically choosing a flink task to execute, use an incoming message as input data for the task and finally deliver the results back to the Camel pipeline. 39.1. Dependencies When using camel-flink with Red Hat build of Camel Spring Boot, add the following Maven dependency to your pom.xml to have support for auto configuration: Maven users will need to add the following dependency to their pom.xml for this component: <dependency> <groupId>org.apache.camel.springboot</groupId> <artifactId>camel-flink-starter</artifactId> </dependency> 39.2. URI Format Currently, the Flink Component supports only Producers. One can create DataSet, DataStream jobs. 39.3. Configuring Options Camel components are configured on two separate levels: component level endpoint level 39.3.1. Configuring Component Options At the component level, you set general and shared configurations that are, then, inherited by the endpoints. It is the highest configuration level. For example, a component may have security settings, credentials for authentication, urls for network connection and so forth. Some components only have a few options, and others may have many. Because components typically have pre-configured defaults that are commonly used, then you may often only need to configure a few options on a component; or none at all. You can configure components using: the Component DSL . in a configuration file (application.properties, *.yaml files, etc). directly in the Java code. 39.3.2. Configuring Endpoint Options You usually spend more time setting up endpoints because they have many options. These options help you customize what you want the endpoint to do. The options are also categorized into whether the endpoint is used as a consumer (from), as a producer (to), or both. Configuring endpoints is most often done directly in the endpoint URI as path and query parameters. You can also use the Endpoint DSL and DataFormat DSL as a type safe way of configuring endpoints and data formats in Java. A good practice when configuring options is to use Property Placeholders . Property placeholders provide a few benefits: They help prevent using hardcoded urls, port numbers, sensitive information, and other settings. They allow externalizing the configuration from the code. They help the code to become more flexible and reusable. The following two sections list all the options, firstly for the component followed by the endpoint. 39.4. Component Options The Flink component supports 5 options, which are listed below. Name Description Default Type dataSetCallback (producer) Function performing action against a DataSet. DataSetCallback dataStream (producer) DataStream to compute against. DataStream dataStreamCallback (producer) Function performing action against a DataStream. DataStreamCallback lazyStartProducer (producer) Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel's routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing. false boolean autowiredEnabled (advanced) Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc. true boolean 39.5. Endpoint Options The Flink endpoint is configured using URI syntax: With the following path and query parameters: 39.5.1. Path Parameters (1 parameters) Name Description Default Type endpointType (producer) Required Type of the endpoint (dataset, datastream). Enum values: dataset datastream EndpointType 39.5.2. Query Parameters (6 parameters) Name Description Default Type collect (producer) Indicates if results should be collected or counted. true boolean dataSet (producer) DataSet to compute against. DataSet dataSetCallback (producer) Function performing action against a DataSet. DataSetCallback dataStream (producer) DataStream to compute against. DataStream dataStreamCallback (producer) Function performing action against a DataStream. DataStreamCallback lazyStartProducer (producer (advanced)) Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel's routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing. false boolean 39.6. Message Headers The Flink component supports 4 message header(s), which is/are listed below: Name Description Default Type CamelFlinkDataSet (producer) Constant: FLINK_DATASET_HEADER The dataset. Object CamelFlinkDataSetCallback (producer) Constant: FLINK_DATASET_CALLBACK_HEADER The dataset callback. DataSetCallback CamelFlinkDataStream (producer) Constant: FLINK_DATASTREAM_HEADER The data stream. Object CamelFlinkDataStreamCallback (producer) Constant: FLINK_DATASTREAM_CALLBACK_HEADER The data stream callback. DataStreamCallback 39.7. Flink DataSet Callback @Bean public DataSetCallback<Long> dataSetCallback() { return new DataSetCallback<Long>() { public Long onDataSet(DataSet dataSet, Object... objects) { try { dataSet.print(); return new Long(0); } catch (Exception e) { return new Long(-1); } } }; } 39.8. Flink DataStream Callback @Bean public VoidDataStreamCallback dataStreamCallback() { return new VoidDataStreamCallback() { @Override public void doOnDataStream(DataStream dataStream, Object... objects) throws Exception { dataStream.flatMap(new Splitter()).print(); environment.execute("data stream test"); } }; } 39.9. Camel-Flink Producer call CamelContext camelContext = new SpringCamelContext(context); String pattern = "foo"; try { ProducerTemplate template = camelContext.createProducerTemplate(); camelContext.start(); Long count = template.requestBody("flink:dataSet?dataSet=#myDataSet&dataSetCallback=#countLinesContaining", pattern, Long.class); } finally { camelContext.stop(); } 39.10. Spring Boot Auto-Configuration The component supports 6 options, which are listed below. Name Description Default Type camel.component.flink.autowired-enabled Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc. true Boolean camel.component.flink.data-set-callback Function performing action against a DataSet. The option is a org.apache.camel.component.flink.DataSetCallback type. DataSetCallback camel.component.flink.data-stream DataStream to compute against. The option is a org.apache.flink.streaming.api.datastream.DataStream type. DataStream camel.component.flink.data-stream-callback Function performing action against a DataStream. The option is a org.apache.camel.component.flink.DataStreamCallback type. DataStreamCallback camel.component.flink.enabled Whether to enable auto configuration of the flink component. This is enabled by default. Boolean camel.component.flink.lazy-start-producer Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel's routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing. false Boolean

Commands:
<dependency> <groupId>org.apache.camel.springboot</groupId> <artifactId>camel-flink-starter</artifactId> </dependency>
flink:dataset?dataset=#myDataSet&dataSetCallback=#dataSetCallback flink:datastream?datastream=#myDataStream&dataStreamCallback=#dataStreamCallback
flink:endpointType
@Bean public DataSetCallback<Long> dataSetCallback() { return new DataSetCallback<Long>() { public Long onDataSet(DataSet dataSet, Object... objects) { try { dataSet.print(); return new Long(0); } catch (Exception e) { return new Long(-1); } } }; }
@Bean public VoidDataStreamCallback dataStreamCallback() { return new VoidDataStreamCallback() { @Override public void doOnDataStream(DataStream dataStream, Object... objects) throws Exception { dataStream.flatMap(new Splitter()).print(); environment.execute("data stream test"); } }; }
CamelContext camelContext = new SpringCamelContext(context); String pattern = "foo"; try { ProducerTemplate template = camelContext.createProducerTemplate(); camelContext.start(); Long count = template.requestBody("flink:dataSet?dataSet=#myDataSet&dataSetCallback=#countLinesContaining", pattern, Long.class); } finally { camelContext.stop(); }