Customizing Deployments

The fly launch command sets you up with a useful starting point, but you can customize just about everything to meet your needs. Here’s a few things that might be useful to know.

Startup Scripts

The fly launch command generated a .fly/scripts directory. Any file in here ending in .sh will run (via bash) anytime your application is started.

These scripts are called from the Docker ENTRYPOINT script (.fly/ before anything else is ran.

By default, fly launch generates a startup script .fly/scripts/, which runs various artisan cache commands such as config:cache, route:cache, and view:cache.

You can enable or disable those as you see fit, as well as add your own .sh scripts!

Release Command

You may want to use the release_command to perform database migrations or other tasks. The release command is run in a temporary VM that is created just before your application is deployed and released. Keep in mind that this temporary VM doesn’t have access to volumes. This potentially helps with zero-downtime deploys.

Note, however, that any Startup Script in .fly/scripts will also be run when a release_command is used.

If you need a startup script to do something (or NOT do something) during a release command, your scripts can detect the presence of the RELEASE_COMMAND environment variable.

if [ -z "$RELEASE_COMMAND" ]; then
    # We are NOT in a temporary VM, run as normal...
    # We are in the temporary VM created
    # for release commands...

Note that release commands run in a temporary VM. Any file-based changes done in the release command (such as artisan view:cache) will be lost when the release command is completed. The subsequently deployed application is a totally different VM. Commands that result in file-based changes (such as artisan view:cache) is best run as a Startup Script.