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Custom Sink Stream

Compile code to write the data processed by DLI to a specified cloud ecosystem or open-source ecosystem.

Syntax

CREATE SINK STREAM stream_id (attr_name attr_type (',' attr_name attr_type)* )
  WITH (
    type = "user_defined",
    type_class_name = "",
    type_class_parameter = ""
  );

Keyword

Table 1 Keyword description

Parameter

Mandatory

Description

type

Yes

Data source type. The value user_defined indicates that the data source is a user-defined data source.

type_class_name

Yes

Name of the sink class for obtaining source data. The value must contain the complete package path.

type_class_parameter

Yes

Input parameter of the user-defined sink class. Only one parameter of the string type is supported.

Precautions

The user-defined sink class needs to inherit the RichSinkFunction class and specify the data type as Row. For example, define MySink class: public class MySink extends RichSinkFunction<Row>{}. It aims to implement the open, invoke, and close functions.

Dependency pom:

<dependency>
	<groupId>org.apache.flink</groupId>
	<artifactId>flink-streaming-java_2.11</artifactId>
	<version>${flink.version}</version>
	<scope>provided</scope>
</dependency>
<dependency>
	<groupId>org.apache.flink</groupId>
	<artifactId>flink-core</artifactId>
	<version>${flink.version}</version>
	<scope>provided</scope>
</dependency>

Example

Writing data encoded in CSV format to a DIS stream is used as an example.

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CREATE SINK STREAM user_out_data (
	count INT
)
  WITH (  
	type = "user_defined", 
	type_class_name = "mySourceSink.MySink", 
	type_class_parameter = ""
      );

To customize the implementation of the sink class, you need to pack the class in a JAR package and upload the UDF function on the SQL editing page.

Parent topic: Custom Stream Ecosystem