SE-1463 add djangoapps.heartbeat to INSTALLED_APPS by default

Description

If this isn't installed, celery workers never see the sample_task used
for the extended heartbeat api call. Since the celery heartbeat check is
turned on by default, we should also make sure this djangoapp and thus
sample_task is installed by default.

Currently, the default configuration causes extended heartbeat to be broken by default.

*JIRA tickets*:

*Dependencies*: None

*Sandbox URL*: TBD - sandbox is being provisioned.

*Merge deadline*: None

*Testing instructions*:

1. deploy edx-platform *on latest master* with the default configuration (ie. no overrides/additions for the installed apps or extended heartbeat checks).
2. visit the extended heartbeat api endpoint (`/heartbeat?extended=true`)
3. verify that the celery heartbeat check is present and fails with `"message": "expired"`
4. verify that `KeyError: u'openedx.core.djangoapps.heartbeat.tasks.sample_task'` is shown in the logs
5. apply the patch from this branch and restart/redeploy the devstack.

*Author notes and concerns*:

  • it is recommended to test this on a local devstack rather than the sandbox (haproxy configuration hides the response when it fails, and ocim adds overrides to installed_apps and extended heartbeat checks by default). If running on a sandbox, you will need to check the extended heartbeat api call locally on the sandbox - eg. `curl localhost:80/heartbeat?extended=true`

*Reviewers*

  • [ ] @viadanna

  • [ ] edX reviewer[s] TBD

*Settings*
```yaml
```

Status

Assignee

David Ormsbee

Reporter

Open Source Pull Request Bot

Labels

Contributor Name

Samuel Walladge

Repo

edx/edx-platform

Customer

Epic Link

None

OSCM Assignee

None

Priority

Unset
Configure