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Running Rake Commands

Last Updated: 22 April 2013

Rake tasks are executed as one-off dynos on Heroku, using the same environment as your app’s dynos. You can run Rake tasks within the remote app environment using the heroku run rake command as follows:

$ heroku run rake db:version
Running `rake db:version` attached to terminal... up, run.1
(in /home/slugs/41913_06f36ef_ab3a/mnt)
Current version: 20081118092504

You can pass Rake arguments, run multiple tasks, and pass environment variables just as you would locally. For instance, to migrate the database to a specific version with verbose backtraces:

$ heroku run rake --trace db:migrate VERSION=20081118092504

After running a migration you’ll want to restart your app with heroku restart to reload the schema and pickup any schema changes.

Limitations

Not all Rake features are supported on Heroku. The following is a list of known limitations:

  • Rake tasks that write to disk, such as rake db:schema:dump, are not compatible with Heroku’s ephemeral filesystem.

  • The db:reset task is not supported. Heroku apps do not have permission to drop and create databases. Use the heroku pg:reset command instead.