gcloud functions deploy streaming --region=${REGION} \\
    --source=./functions/streaming --runtime=python37 \\
    --stage-bucket=${FUNCTIONS_BUCKET} \\
    --trigger-bucket=${FILES_SOURCE}

This code deploys a Cloud Function written in Python, which is named streaming. It is triggered whenever a file is added to your FILES_SOURCE bucket.

describe deployed functions

gcloud functions describe streaming  --region=${REGION} \\
    --format="table[box](entryPoint, status, eventTrigger.eventType)"