Releases

Last updated 18 January 2019

Whenever you deploy code, change a config var, or modify your app’s add-on resources, Heroku creates a new release and restarts your app. You can view your app’s release history, and temporarily roll back to a previous release in the event of a bad deploy or config change.

Release creation

Your app’s first release is named v1, and this number increments with each subsequent release.

In this example, a code deploy creates release v10:

$ git push heroku master
...
-----> Compressing... done, 8.3MB
-----> Launching... done, v10
       http://severe-mountain-793.herokuapp.com deployed to Heroku

As mentioned, releases are also created whenever you modify your app’s config vars or add-on resources.

Listing release history

Use the heroku releases command to see your app’s release history:

$ heroku releases
Rel   Change                          By                    When
----  ----------------------          ----------            ----------
v52   Config add AWS_S3_KEY           jim@example.com       5 minutes ago
v51   Deploy de63889                  stephan@example.com   7 minutes ago
v50   Deploy 7c35f77                  stephan@example.com   3 hours ago
v49   Rollback to v46                 joe@example.com       2010-09-12 15:32:17 -0700

The value of the Change column indicates the cause of each release. For deployments, this value includes the hash of the Git commit that was deployed. Use this hash to correlate changes in a release with changes in your Git repository. For example:

$ git log -n 1 de63889
commit de63889c20a96347679af2c5160c390727fa6749
Author: <stephan@example.com>
Date:   Thu Jul 11 17:16:20 2013 +0200
Fixed listing CSS and localization of description.

You can get detailed info on a release with the heroku releases:info command:

$ heroku releases:info v24
=== Release v24
Change:      Deploy 575bfa8
By:          jim@example.com
When:        6 hours ago
Addons:      deployhooks:email, releases:advanced
Config:      MY_CONFIG_VAR => 42
             RACK_ENV      => production

Rollback

If you deploy buggy code to production that you need to roll back, whenever possible you should simply revert the relevant code changes locally with git revert and redeploy.

If you need to roll back a release due to incorrect configuration or other Heroku-platform-specific issues, you can use the heroku rollback command. This command rolls your app back to a previous release:

$ heroku rollback v40
Rolled back to v40

If you don’t specify a release number, your app is rolled back by a single release.

The heroku rollback command creates a new release. This release copies the compiled slug and config vars (including add-on-related config vars) of the release you are rolling back to.

The heroku rollback command does not roll back the state of any of the following:

  • Add-on provisioning (provisioned add-ons remain provisioned, and deprovisioned add-ons remain deprovisioned)
    • Note that any add-on-related config vars do roll back.
  • Your app’s Heroku-hosted Git repository
  • Any state stored in add-ons or externally

It is your responsibility to reconcile these resources after rolling back. Consequently, you should use the heroku rollback command only when absolutely necessary.

Running on a rolled-back release should serve as a temporary fix to a bad deployment. If you are running on a rolled-back release, commit a fix to your encountered issue and push it to Heroku. As always, this updates the heroku Git remote and creates a new release.

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