Ruby on Azure App Service

Notes

• Current version (tag) in production is 2.3-1 dockerhub
• 2.3-0 does not work with current build of App Service
• We are currently working on adding support for Rails 5.1 and Yarn dependency management, until then it's recommended that you remove the package.json from your solution and manually copy any built dependencies through yarn to your site through ftp
• If you set your RAILS_ENV to development, you may need to update your appcommandline to be "rails server -b 0.0.0.0" , otherwise it will run on localhost by default and the server won't be exposed outside the container.

Changes from 2.3-0 - 2.3-1

• Move startup steps from behind-the-scenes to startup.sh
• Remove passenger from default startup
• Logs are 100% stored in home/LogFiles/docker (container stdout)

About the docker image

This ruby image is built around the idea that it does not contain the site itself, rather the site will be mounted to the home/site/wwwroot directory. The site is assumed to have packaged gems in the vendor/bundle folder and gems cached in vendor/cache. These steps are taken care of in Kudu during deployment. In app service, the site exists on a shared volume and is mounted to into the container on each worker.

Key Points for Running Ruby Site

• Default sites run in "production" mode. Make sure your site runs in production mode locally before trying on app service.
• Gems are installed and packaged on deployment, do not push vendored gems to the site.

Ruby-Specific AppSettings

These app settings are checked for and honored in ruby site deployment on app service.

Deployment specific appsettings

• BUNDLE_WITHOUT - in Kudu, this setting will be set as such: "bundle install --without $BUNDLE_WITHOUT" (multiple w/ comma-separated list ie. development,production
• ASSETS_PRECOMPILE - if set, we run "bundle exec rake --trace assets:precompile" in deployment through kudu

Site container specific appsettings

• SECRET_KEY_BASE - if not set we will set it for you
• RAILS_ENV - if not set, we default to 'production' and run it as 'rails server -e $RAILS_ENV'
• APP_COMMAND_LINE - overrides the 'rails server' command. Make sure your site starts on port 3000 unless specified through $PORT

Deployment steps

When a site is deployed to App Service using git, the Kudu site (appsvc/kudu:1.4) will run a series of steps on the site to make it deployment ready.

1. Check for existence of Gemfile
2. run bundle clean to remove any changed/unnecessary gems
3. run bundle install --path "vendor/bundle" to install gems to vendor folder. $OPTIONS will turn into any --without parameters.
4. run bundle package to package gems into vendor/cache folder
5. If $ASSETS_PRECOMPILE is defined as true, then we run bundle exec rake --trace assets:precompile

Site startup

If you look at the startup.sh file you will see the steps taken when the site container starts.

1. Generate $SECRET_KEY_BASE if the user hasn't provided one already (to allow running in production mode)
2. Default $RAILS_ENV to production if not specified
3. remove any pid files from tmp/pids
4. run bundle check in vendor/bundle to make sure all dependencies are satisfied, if not, container fails to start (this is because gems shouldn't be installed on site start, only in deployment. So if check fails, run deployment again or install gems locally and directly drop them into the vendor folder.
5. Run bundle install --local --deployment just in case. If a gem doesn't exist then it will try to install the gem from the vendor/cache folder but won't try to download from the "source" defined in Gemfile.
6. If $APP_COMMAND_LINE is not set, default to rails server -e $RAILS_ENV, otherwise run $APP_COMMAND_LINE to start the server.

Tutorials

A few "quick start" tutorials will be available to help you develop using our service.

hello world

github deployment

rails + bootstrap (serving static assets + debugging)

Troubleshooting

In your site contents directory (you can access via ftp or kudu/scm site), look for LogFiles/docker and all docker output will be sent to those files. Feel free to give feedback on any container issues, this image is still being developed.