Socket

Socket sink connector

Support Those Engines

Spark
Flink
SeaTunnel Zeta

Key features

• exactly-once

Description

Used to send data to a socket server in streaming or batch mode. Each SeaTunnel row is serialized to a JSON object via JsonSerializationSchema and written to the configured TCP port. The connector does not append any delimiter at all — neither a newline, nor any other separator between records. Multiple records therefore travel as one undelimited, continuous TCP byte stream of concatenated JSON objects (for example {"a":1}{"a":2}{"a":3}). The output is explicitly not line-framed JSON, so the peer must handle framing itself: parse consecutive JSON values with a streaming JSON parser (such as Jackson's MappingIterator) rather than a line-oriented parser. Tools like nc -l only echo the raw concatenated bytes, so they are useful for a quick single-row check but cannot split records on their own.

For example, if the data from upstream is [age: 12, name: jared], the content send to socket server is the following: {"name":"jared","age":17}

Sink Options

Name	Type	Required	Default	Description
host	String	Yes		socket server host
port	Integer	Yes		socket server port
max_retries	Integer	No	3	The number of retries to send record failed. Set to -1 to retry indefinitely, or 0 to fail immediately.
common-options		No	-	Sink plugin common parameters, please refer to Sink Common Options for details

tip

Socket sink is mainly used for local debugging and simple integrations. It reconnects and retries failed writes according to max_retries, but it does not provide exactly-once delivery. The TCP client opens one connection per writer; host/port are the server endpoint that this client connects to.

Task Example

This is randomly generated data written to the Socket side

env {
  parallelism = 1
  job.mode = "STREAMING"
}

source {
  FakeSource {
    plugin_output = "fake"
    schema = {
      fields {
        name = "string"
        age = "int"
      }
    }
  }
}

sink {
  Socket {
    host = "localhost"
    port = 9999
    max_retries = 3
  }
}

• Start a port listening

nc -l -v 9999

• Start a SeaTunnel task

• Socket Server Console print data. No delimiter is appended, so multiple rows arrive as concatenated JSON objects in the raw byte stream (line breaks shown here only for readability):

{"name":"jared","age":17}{"name":"jared","age":18}...

Changelog

Change Log

Change	Commit	Version
[improve] socket options (#9517)	https://github.com/apache/seatunnel/commit/af83a302cf	2.3.12
[Feature][Restapi] Allow metrics information to be associated to logical plan nodes (#7786)	https://github.com/apache/seatunnel/commit/6b7c53d03c	2.3.9
[Improve] Remove use SeaTunnelSink::getConsumedType method and mark it as deprecated (#5755)	https://github.com/apache/seatunnel/commit/8de7408100	2.3.4
[Improve][build] Give the maven module a human readable name (#4114)	https://github.com/apache/seatunnel/commit/d7cd601051	2.3.1
[Improve][Project] Code format with spotless plugin. (#4101)	https://github.com/apache/seatunnel/commit/a2ab166561	2.3.1
[Feature][Connector] add get source method to all source connector (#3846)	https://github.com/apache/seatunnel/commit/417178fb84	2.3.1
[Hotfix][OptionRule] Fix option rule about all connectors (#3592)	https://github.com/apache/seatunnel/commit/226dc6a119	2.3.0
[Improve][Connector-V2][Socket] Unified exception for socket source & sink connector (#3511)	https://github.com/apache/seatunnel/commit/581292f210	2.3.0
[feature][connector][socket] Add Socket Connector Option Rules (#3317)	https://github.com/apache/seatunnel/commit/b85317bcbe	2.3.0
[Improve][all] change Log to @Slf4j (#3001)	https://github.com/apache/seatunnel/commit/6016100f12	2.3.0-beta
[DEV][Api] Replace SeaTunnelContext with JobContext and remove singleton pattern (#2706)	https://github.com/apache/seatunnel/commit/cbf82f755c	2.2.0-beta
[#2606]Dependency management split (#2630)	https://github.com/apache/seatunnel/commit/fc047be69b	2.2.0-beta
[Feature][Connector-V2] Socket Connector Sink (#2549)	https://github.com/apache/seatunnel/commit/94f4600a4e	2.2.0-beta
[api-draft][Optimize] Optimize module name (#2062)	https://github.com/apache/seatunnel/commit/f79e3112b1	2.2.0-beta