My web server tries to connect to fluentd before listening port on docker

Question

I want to run my ASP.NET Core web api server and fluentd for its logging driver with docker-compose. My docker-compose.yml is like below.

version: "2"
services:
  web:
    build:
      context: ..
      dockerfile: ./DockerTest/Dockerfile
    container_name: web
    depends_on: [ fluentd ]
    networks:
      test_net:
       ipv4_address: 172.20.10.1
    ports:
      - "8080:80"
    logging:
      driver: fluentd
      options:
        fluentd-address: 172.20.10.4:24224
        tag: "web.log"
  fluentd:
    build:
      context: ./fluentd
      dockerfile: Dockerfile
    container_name: fluentd
    volumes:
      - ./fluentd/conf:/fluentd/etc
    networks:
      test_net:
        ipv4_address: 172.20.10.4
    ports:
      - "24224:24224"
      - "24224:24224/udp"
networks:
  test_net:
    ipam:
      config:
        - subnet: 172.20.0.0/16

If I run web server after fluentd is fully executed, it works fine. But if I run with command docker-compose up, my web server is started before fluentd makes following logs.

[info]: #0 listening port port=24224 bind="0.0.0.0"
[info]: #0 fluentd worker is now running worker=0

So the web server fails to start with error.

Error response from daemon: failed to initialize logging driver: dial tcp 172.20.10.4:24224: connect: connection refused.

I tried to add depends_on and links, but both are not working.

Answer 1

I solved this using fluentd-async-connect option.

logging:
      driver: fluentd
      options:
        fluentd-address: 172.20.10.4:24224
        fluentd-async-connect: "true"
        fluentd-retry-wait: 1s
        fluentd-max-retries: 30
        tag: "web.log"

It will try to re-connect after each connection fail.