How can I wait for a docker container to be up and running?

Solution 1:

Found this simple solution, been looking for something better but no luck...

until [ "`docker inspect -f {{.State.Running}} CONTAINERNAME`"=="true" ]; do
    sleep 0.1;
done;

or if you want to wait until the container is reporting as healthy (assuming you have a healthcheck)

until [ "`docker inspect -f {{.State.Health.Status}} CONTAINERNAME`"=="healthy" ]; do
    sleep 0.1;
done;

Solution 2:

As commented in a similar issue for docker 1.12

HEALTHCHECK support is merged upstream as per docker/docker#23218 - this can be considered to determine when a container is healthy prior to starting the next in the order

This is available since docker 1.12rc3 (2016-07-14)

docker-compose is in the process of supporting a functionality to wait for specific conditions.

It uses libcompose (so I don't have to rebuild the docker interaction) and adds a bunch of config commands for this. Check it out here: https://github.com/dansteen/controlled-compose

You can use it in Dockerfile like this:

HEALTHCHECK --interval=5m --timeout=3s \
  CMD curl -f http://localhost/ || exit 1

Official docs: https://docs.docker.com/engine/reference/builder/#/healthcheck

Solution 3:

If you don't want to expose the ports, as is the case if you plan to link the container and might be running multiple instances for testing, then I found this was a good way to do it in one line :) This example is based on waiting for ElasticSearch to be ready:

docker inspect --format '{{ .NetworkSettings.IPAddress }}:9200' elasticsearch | xargs wget --retry-connrefused --tries=5 -q --wait=3 --spider

This requires wget to be available, which is standard on Ubuntu. It will retry 5 times, 3 seconds between tries, even if the connection is refused, and also does not download anything.