App Engine deployment pipe fails to deploy Spring Boot app

[mklosinski]

I'm testing out Bitbucket Pipe for GCloud App Engine deployment. It turns out the deployment fails with the following message, stating that Java environment is missing:

INFO: Starting deployment to GCP app engine...
gcloud app deploy src/main/webapp/WEB-INF/appengine-web.xml --quiet
The component [app-engine-java] is required for staging this 
application.
Your current Cloud SDK version is: 242.0.0
Installing components from version: 242.0.0
+----------------------------------------------------+
| These components will be installed. |
+------------------------------+---------+-----------+
| Name | Version | Size |
+------------------------------+---------+-----------+
| Cloud Datastore Emulator | 2.1.0 | 18.4 MiB |
| gRPC python library | 1.9.1 | 12.1 MiB |
| gRPC python library | | |
| gcloud app Java Extensions | 1.9.73 | 104.8 MiB |
| gcloud app Python Extensions | 1.9.85 | 6.0 MiB |
+------------------------------+---------+-----------+
For the latest full release notes, please visit:
https://cloud.google.com/sdk/release_notes
#============================================================#
#= Creating update staging area =#
#============================================================#
#= Installing: Cloud Datastore Emulator =#
#============================================================#
#= Installing: gRPC python library =#
#============================================================#
#= Installing: gRPC python library =#
#============================================================#
#= Installing: gcloud app Java Extensions =#
#============================================================#
#= Installing: gcloud app Python Extensions =#
#============================================================#
#= Creating backup and activating new installation =#
#============================================================#
Performing post processing steps...
...........................................................done.
Update done!
Restarting command:
$ gcloud app deploy src/main/webapp/WEB-INF/appengine-web.xml --quiet
ERROR: (gcloud.app.deploy) To use the local staging for java, a Java 7+ JRE must be installed and on your system PATH
Deployment failed.

I manually examined the pipe Docker container and indeed it doesn't seem to have any Java installed:

docker run -i -t --entrypoint /bin/bash bitbucketpipelines/google-app-engine-deploy:0.3.1
bash-4.4# java -version
bash: java: command not found

[Andrew Reed]

I got around this, somewhat, by using atlassian/google-app-engine-deploy:0.3.0 (version 0.3.0 instead of 0.3.1). I looked at the sizes of the two versions on dockerhub and noticed a very large difference in size. Assumed that a JRE was missing and thought I'd have nothing to lose in trying the downgrade.

So I get messages that tell me the app has deployed successfully, however something is still not right with it, as when I go to use it I get a "404 Not Found" - and the stackdriver logs aren't really telling me much yet. But according to the appengine dashboard the correct version of application seems to be running and available.