Docker is a system for isolating a build environment and is suitable for deploying plots2 with a predictable environment.
Plots2 requires a number of services to function. We use docker-compose to start up required services and parallel processes.
In order to configure our container we use both a configuration file and environment variables.
The configuration file is under /containers/ directory:
docker-compose-production.yml
docker-compose-stable.yml
docker-compose-testing.yml
docker-compose-unstable.yml
Container should not include secrets (API keys, passwords, credentials). Therefore we make an environment.sh file which assigns the variables needed for operation.
Currently (Nov 2018) the variables in use are:
SECRET_KEY_BASE RAILS_ENV COMPOSE_FILE HA_SITE_KEY RECAPTCHA_SECRET_KEY OAUTH_GOOGLE_APP_KEY OAUTH_GOOGLE_APP_SECRET OAUTH_GITHUB_APP_KEY OAUTH_GITHUB_APP_SECRET SERVER_ADDRESS (pop3) USERNAME (pop3) EMAIL_PASSWORD (pop3) OAUTH_TWITTER_APP_KEY OAUTH_TWITTER_APP_SECRET OAUTH_FACEBOOK_APP_KEY OAUTH_FACEBOOK_APP_SECRET TWITTER_CONSUMER_KEY TWITTER_CONSUMER_SECRET TWITTER_ACCESS_TOKEN TWITTER_ACCESS_TOKEN_SECRET TWEET_SEARCH WEBSITE_HOST_PATTERN GMAPS_API_KEY
We use the same variables in our Jenkins staging service (but those are configured thru the GUI).
We do not keep our environment.sh in version control.
docker-compose exec will execute commands on a running container. We use this in production in order to inject the IP address of the email service into the routing table of the container host (echo 172.19.0.1 smtp >> /etc/hosts). We have to do this in every container that needs to send mail (e.g. sidekiq, mailman and web. We also start cron this way.
So a started plots2 docker-compose is not ready for email until cron has been started, and whenever gem has updated the crontab.
This process has been automated in our staging and production servers by using the Makefile. Type make deploy-container in order to deploy a new container, and make redeploy-container in order to attempt to do the same with shutting down an already running container.
It is possible to run the test suite by issuing make test-container. Remember to set RAILS_ENV=test in that case.
You need to tell docker-compose which compose file you are using by using the -f containers/docker-compose-... option.
This can be avoided by setting the COMPOSE_FILE variable.
It is useful to run docker-compose logs to figure out when something is affecting a specific container.