Execute specific command when receive Google Cloud Pub/Sub message
How to use
Create a Service Account and prepate credential.
If run in GCE/Cloud Run, use Application Default Credentials
If run in outside of Google Cloud, generate a service account key file and specify the path to it in GOOGLE_APPLICATION_CREDENTIALS environment variable.
Create a Pub/Sub subscription and grant Pub/Sub subscriber privileges to service account
Recommend setting the subscription expiration date to indefinite