production migrate command about dockerizing-django

[oppianmatt]

Where did you see docker-compose is removing links?

docker is removing legacy container links https://docs.docker.com/engine/userguide/networking/default_network/dockerlinks/

I believe links are still there, just now with the network. On the docker-compose links reference page:

Links also express dependency between services in the same way as depends_on, so they determine the order of service startup.

Note: If you define both links and networks, services with links between them must share at least one network in common in order to communicate.

So links is still used, and used to determine startup order. So if web links to postgres then running web will also start postgres first.

# built the containers if needed
$ docker-compose -f production.yml build
# migrate if needed, will automatically start postgres, run this if pulling new migrations down
$ docker-compose -f production.yml run web python -u manage.py migrate
# start up anything that hasn't already started
$ docker-compose -f production.yml up -d

Note if postgres is restart always, it will be started anyway.

For windows/mac users the migrate command needs to be:

# windows/mac users have to run in detach mode
$ docker-compose -f production.yml run -d web python -u manage.py migrate --noinput
# but you can still monitor progress
$ docker-compose logs <containername>

[mjhea0]

You would at least need to get Postgres up before running the migrations if you handle it that way.

[oppianmatt]

With the links in compose it will start the postgres container when you run the web container to do the migrate.

If you don't do the migrate first AND there are new migrations it might error on startup until you run migrate. For example if you have pulled new migrations down from in a team.

[mjhea0]

Your suggestion is to remove the links and then run the commands in this order? @oppianmatt

$ docker-compose -f production.yml build
$ docker-compose -f production.yml run web python -u manage.py migrate
$ docker-compose -f production.yml up -d

[oppianmatt]

no keep the links but do the run migrate first. It will start up postgres as needed and apply any migrations that might be in the source and not in the db.

[mjhea0]

I believe Docker is removing links altogether in the next release. May be worth removing them now. Also the DB would have to be up, so the commands would need to be:

$ docker-compose -f production.yml build
$ docker-compose -f production.yml up postgres -d
$ docker-compose -f production.yml run web python -u manage.py migrate
$ docker-compose -f production.yml up -d