1344716 - use healthchecks to block on successful container startup

Status: RESOLVED FIXED

(Release Engineering Graveyard :: Applications: Balrog (backend), enhancement, P2)

Description

[[e-mail] (:bhearsum)]

We have 5 docker containers in our docker-compose.yml, and some dependencies between them. Right now, we don't really enforce those dependencies well. Eg: balrogadmin simply sleeps before starting up (to wait for the database), and balrogagent just spews errors until balrogadmin is started.

As of Docker 1.12.0, there's a new "healthcheck" feature that can be used to delay a container startup until the healthcheck command is successful. http://stackoverflow.com/questions/31746182/docker-compose-wait-for-container-x-before-starting-y/41854997#41854997 has a very relevant example.

For our purposes, we'll want:
* balrogadmin to wait until mysql is up (we can probably use nc to check port 3306 of the balrogdb container for this)
* balrogpub to wait until mysql is up
* balrogagent to wait until balrogadmin is up (we can probably use a similar curl command as the stackoverflow link for this)
* balrogui to wait until balrogadmin is up

Comment 1

[[github robot]]

Commit pushed to master at https://github.com/mozilla/balrog

https://github.com/mozilla/balrog/commit/b74d1fba10a43d0bea91fd1ea70218ac9bbead6d
Bug 1344716: Add health checks to Docker-compose file (#297). r=bhearsum

Comment 2

[[e-mail] (:bhearsum)]

This is a great improvement to the developer experience, thank you Durodola!