Report any errors from the backend script to Slack.

[zigouras]

Is your feature request related to a problem? Please describe. This morning the scheduled backend job failed with the error below: cleanandgreenphl@backend:~/clean-and-green-philly/data$ docker logs data-vacant-lots-proj-run-bd197eebfaa5 2>&1 | grep -i error "ValueError: tmp/temp_vacant_properties_tiles_merged.pmtiles is 4557995 bytes in size but should be at least 5242880. Therefore, we are not uploading any files to the GCP bucket. The file may be corrupt or incomplete."

If the backend job fails, we will know indirectly by the fact that the diff report will not get sent to the clean-and-green-philly-back-end Slack channel. However, it would be better to have the error directly reported to the Slack channel.

Describe the solution you'd like Modify the Python code of the backend script to send a message to Slack on any exception raised. This can be done by putting a try/catch block around all of the logic in the script.py Python code. Then use the existing Slack API and credentials to send the error message to the channel. See existing code in diff_report.py::send_report_to_slack

Once the change has been made in the staging branch, do a git fetch and git pull in the project directory on the GCP VM to deploy the latest code to the scheduled job.

Describe alternatives you've considered If there is a better way to do this, please suggest.

Additional context Supply unit tests with the code change.