flink-mcp

flink-mcp — Flink MCP Server

This project provides an MCP server that connects to Apache Flink SQL Gateway.

Prerequisites

• A running Apache Flink cluster and SQL Gateway

  • Start cluster: ./bin/start-cluster.sh
  • Start gateway: ./bin/sql-gateway.sh start -Dsql-gateway.endpoint.rest.address=localhost
  • Verify: curl http://localhost:8083/v3/info

• Configure environment:

  • Set SQL_GATEWAY_API_BASE_URL (default http://localhost:8083). You can use a .env file at repo root.

Run

Install and run via the console script:

pip install -e .
flink-mcp

MCP clients should launch the server over stdio with command: flink-mcp.

Ensure SQL_GATEWAY_API_BASE_URL is set in your environment or .env.

Tools (v0.2.5)

• flink_info (resource): returns cluster info from /v3/info.
• open_new_session(properties?: dict) -> { sessionHandle, ... }.
• get_config(sessionHandle: str): returns session configuration.
• configure_session(sessionHandle: str, statement: str): apply session-scoped DDL/config (CREATE/USE/SET/RESET/LOAD/UNLOAD/ADD JAR).
• run_query_collect_and_stop(sessionHandle: str, query: str, max_rows: int=5, max_seconds: float=15.0): execute, fetch up to N rows within T seconds, then STOP the job if a jobID is present; closes the operation.
• run_query_stream_start(sessionHandle: str, query: str): execute a streaming query and return { jobID, operationHandle }; the job is left running.
• fetch_result_page(sessionHandle: str, operationHandle: str, token: int): fetch a single page; returns { page, nextToken, isEnd }.
• cancel_job(sessionHandle: str, jobId: str): issue STOP JOB '<jobId>', wait until DESCRIBE JOB status is not RUNNING; returns { jobID, status, jobGone, jobStatus }.

Notes

• Tools are stateless; clients manage and pass session/operation handles explicitly.

• run_query_stream_start returns both jobID and operationHandle; use fetch_result_page to stream results.

• cancel_job issues STOP and waits using DESCRIBE JOB; close_operation is invoked internally where appropriate.

• Endpoints target SQL Gateway v3-style paths.