I am using rabbitmq and a simple python sample from here
together with docker-compose. My problem is that I need to wait for rabbitmq to fully started. From what I searched so far, I don’t know how to wait with container x ( in my case worker ) until y (rabbitmq) is started.
Usage: docker wait CONTAINER [CONTAINER…]
Block until a container stops, then print its exit code.
Waiting for a container to stop is maybe not what I am looking for but if
it is, is it possible to use that command inside the docker-compose.yml ?
My solution so far is to wait some seconds and check the port, but is this the way to achieve this?. If I don’t wait I get an error.
worker: build: myapp/. volumes: - myapp/.:/usr/src/app:ro links: - rabbitmq rabbitmq: image: rabbitmq:3-management
python hello sample (rabbit.py):
import pika import time import socket pingcounter = 0 isreachable = False while isreachable is False and pingcounter < 5: s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) try: s.connect(('rabbitmq', 5672)) isreachable = True except socket.error as e: time.sleep(2) pingcounter += 1 s.close() if isreachable: connection = pika.BlockingConnection(pika.ConnectionParameters( host="rabbitmq")) channel = connection.channel() channel.queue_declare(queue='hello') channel.basic_publish(exchange='', routing_key='hello', body='Hello World!') print (" [x] Sent 'Hello World!'") connection.close()
Dockerfile for worker:
FROM python:2-onbuild RUN ["pip", "install", "pika"] CMD ["python","rabbit.py"]
Update Nov 2015:
A shell script or waiting inside your program is maybe a possible solution. But after seeing this Issue I am looking for a command or feature of docker/docker-compose itself.
They mention a solution for implementing a health check, which may be the best option. A open tcp connection does not mean your service is ready or may remain ready. In addition to that I need to change my entrypoint in my dockerfile.
So I am hoping for an answer with docker-compose on board commands, which will hopefully the case if they finish this issue.
Update March 2016
There is a proposal for providing a built-in way to determine if a container is “alive”. So docker-compose can maybe make use of it in near future.
Update June 2016
It seems that the healthcheck will be integrated into docker in Version 1.12.0
Update January 2017
I found a docker-compose solution see:
Docker Compose wait for container X before starting Y