Docker Compose gRPC Health

docker-compose-grpc-health-check.md

Minimal linux version for all of those gRPC services that don't provide health port.

Example with gripmock

  gripmock:
    image: gripmock/gripmock
    ports:
      - "${STUB_GRPC_PORT}:${STUB_GRPC_PORT}"
      - "${STUB_ADMIN_PORT}:${STUB_ADMIN_PORT}"
    volumes:
      - ./stubs/service/protos:/proto:ro
      - ./stubs/service/stubs:/stubs:ro
    healthcheck:
        # note: this checks for without netstat/nc/other tools. Also, docker is tcp6.
        test: ["CMD-SHELL", "grep -q :$(printf '%04X' $$STUB_GRPC_PORT) /proc/net/tcp6"]
        interval: 3s
        timeout: 2s
        retries: 15
    command: --admin-port ${STUB_ADMIN_PORT} --grpc-port ${STUB_GRPC_PORT} --stub=/stubs /proto/service/v1/pservice.proto

The trick is here: grep -q :$(printf '%04X' $$STUB_GRPC_PORT) /proc/net/tcp6:

• printf '%04X' $$STUB_GRPC_PORT will HEX the readable (decimal) port number
• /proc/net/tcp6 is docker default, the port will appear here once it's opened (i.e. service started successfully)