gcloud app deploy does not terminate even when service is running - google-app-engine

Question

I am deploying a node.js server to Google App Engine from Bitbucket pipeline environment and the last command in the script is: gcloud -q app deploy app.yaml --no-promote --verbosity=debug
The logs show that the service is deployed successfully but the script is not terminating, this is the last part of the log:
> DEBUG: Reading GCS logfile: 206 (read 10 bytes) PUSH DONE DEBUG:
> Operation [...] complete. Result: {...} DEBUG: Reading GCS logfile:
> 416 (no new content; keep polling)
> -------------------------------------------------------------------------------- DEBUG: Converted YAML to JSON: "{...}" DEBUG: Operation [...] not
> complete. Waiting to retry. Updating service [default] (this may take
> several minutes)... .DEBUG: Operation [...] not complete. Waiting to
> retry. ......DEBUG: Operation [...] not complete. Waiting to retry.
> .......DEBUG: Operation [...] not complete. Waiting to retry.
> ......DEBUG: Operation [...] not complete. Waiting to retry.
> .......DEBUG: Operation [...] not complete. Waiting to retry.
> .......DEBUG: Operation [...] not complete. Waiting to retry.
I tried to add readiness_check and liveness_check to app.yml but it didn't change the behaviour.
readiness_check:
path: "/api/public/logout"
check_interval_sec: 5
timeout_sec: 4
failure_threshold: 2
success_threshold: 2
app_start_timeout_sec: 300
liveness_check:
path: "/api/public/logout"
check_interval_sec: 30
timeout_sec: 4
failure_threshold: 2
success_threshold: 2
The main unknown here is what criteria does gcloud app deploy uses to determine termination condition?
Also, is there any bypass to this problem?
Update
The problem happens also when running the gcloud app deploy command from local environment (my laptop).
The problem does NOT happen when removing the --no-promote flag.

Answer 1

The gcloud app deploy command expects a well-formed and valid app.yml file, this is what determines its termination condition.
As you confirmed the deployment worked without the --no-promote flag, it could mean that something in the configuration expects the application to be already deployed and running, thus preventing the script to complete.
Another possible cause would be that the Google Cloud SDK version specified in bitbucket-pipelines.yml is an older one. Make sure you work with the latest. This consideration applies extensively to all dependencies in package.json, which might be conflicting with one another, especially when using older versions of Node.js.
This guide can help at building a sound configuration for Bitbucket-based deployments; although the example given is with Python, it might as well be used as a template for processing a Node.js pipeline.
Nb. in this solution, the Google Cloud SDK version is an older one (127.0.0), which will make this deployment fail, so it should be replaced with the latest (228.0.0 or higher). Also the guide omits another required API activation: Cloud Build API. I've notified the team to amend the solution.
I've tested several scenarios with a simple Node.js server, and could not reproduce the issue. Check my Github repository for the code.
For further help on this topic, please provide more hints, such as the content of the app.yml, bitbucket-pipelines.yml, and package.json files, as well as a description of the state of App Engine (services, versions).
In order to deploy the test repository to App Engine from Bitbucket, make sure the following is done on the project:
Enable API's:
App Engine Admin
Cloud Build
Create a Service Account with following permissions, and generate an API Key:
App Engine: Admin
Cloud Build: Editor
Storage: Object Admin