ruby on rails - Heroku - Display hash of current commit in browser

Question

I want to display the hash of the current git commit in the browser so that testing team (which does not have an access to run heruko commands) will be able to include the corresponding commit hash in bug reports.

First I tried grit, but something is broken and it doesn't work on Heroku (on local it works great, I don't know why it fails on Heroku).

So I found out that there are two environment variables on Heroku:

ENV["COMMIT_HASH"]
ENV["LAST_COMMIT_BY"]

But neither of them is available (both are nil).

I also checked with:

heroku config

But again, neither is set.

Is there a way to retrieve the hash information? Is there any way to have more git information, such as date for example?

Answer 1

It's now possible to try the Heroku feature Roberto wrote about in his answer, without contacting Heroku. It's called Heroku Labs: Dyno Metadata and you can enable it by

heroku labs:enable runtime-dyno-metadata -a <app name>

and then the information is available (on the next deploy) as environment variables:

~ $ env
HEROKU_APP_ID:                   9daa2797-e49b-4624-932f-ec3f9688e3da
HEROKU_APP_NAME:                 example-app
HEROKU_DYNO_ID:                  1vac4117-c29f-4312-521e-ba4d8638c1ac
HEROKU_RELEASE_VERSION:          v42
HEROKU_SLUG_COMMIT:              2c3a0b24069af49b3de35b8e8c26765c1dba9ff0
HEROKU_SLUG_DESCRIPTION:         Deploy 2c3a0b2
...