Allow passing of custom JSON body in Outgoing Notifications of Gatsby Cloud

[dumitrualex]

Hello 👋 ,

While trying to integrate Gatsby build process with our CMS SaaS (DatoCMS) I realised Gatsby is missing one integration feature that could come in handy. The scenario is that, while I have the option to create a POST request to a custom URL, the other side has a generic endpoint and is expecting a custom JSON body stating the build status.

In case of DatoCMS, this is an excerpt from their build trigger setup, showing they expect a custom JSON body to a generic URL:

Step 2: Status notifications

After each build, make sure to notify DatoCMS with the status of the publishing operation with a POST request to the following URL:

# Successful build notification example
curl -n -X POST https://webhooks.datocms.com/123/deploy-results \
  -H 'Content-Type: application/json' \
  -d '{ "status": "success" }'

# Failed build notification example
curl -n -X POST https://webhooks.datocms.com/123/deploy-results \
  -H 'Content-Type: application/json' \
  -d '{ "status": "error" }'

Since the information provided in the JSON body from Gatsby, by default, doesn't map to the above specifications, it would be nice to have the opportunity to set our own, when needed.

This feature would speed up the integration efforts, since we wouldn't be forced to funnel these notifications through a custom solution just to map out the correct status updates.

Thank you in advance for taking this request into consideration.

Kind regards,
Alex Dumitru