refactor(gce): Refactor BasicGoogleDeployHandler to be more readable and testable

[edgarulg]

Key point about the refactor.

1. I translated the whole class BasicGoogleDeployHandler into java.
2. I split up the handle method into small single responsibility methods.
3. I defined unit testing for most of the new methods I created to prove functionality.
4. I do not include any new feature or change that was not defined by the BasicGoogleDeployHandler before.

Related to: spinnaker/spinnaker#6985

[edgarulg]

I published and deployed a snapshot version with my refactor and I validated a GCE deploy worked as expected. I didn't tests all possible configurations as part of my e2e validation.

[edgarulg]

@Mergifyio refresh

[mergify]

refresh

✅ Pull request refreshed

[edgarulg]

@Mergifyio rebase

[mergify]

rebase

☑️ Nothing to do

• -conflict [📌 rebase requirement]
• -closed [📌 rebase requirement]
• queue-position = -1 [📌 rebase requirement]
• any of:
  • #commits > 1 [📌 rebase requirement]
  • #commits-behind > 0 [📌 rebase requirement]
  • -linear-history [📌 rebase requirement]

[dbyron-sf]

How did this ever work before?

[edgarulg]

In line: https://github.com/spinnaker/clouddriver/blob/master/clouddriver-google/src/main/groovy/com/netflix/spinnaker/clouddriver/google/deploy/GCEUtil.groovy#L924
It creates a Scheduling object in runtime. Groovy is flexible enough to allow a different object in runtime and it only pass the object to the InstanceProperties object:
https://github.com/spinnaker/clouddriver/blob/master/clouddriver-google/src/main/groovy/com/netflix/spinnaker/clouddriver/google/deploy/handlers/BasicGoogleDeployHandler.groovy#L390
https://github.com/spinnaker/clouddriver/blob/master/clouddriver-google/src/main/groovy/com/netflix/spinnaker/clouddriver/google/deploy/handlers/BasicGoogleDeployHandler.groovy#L428

that is how this works but I don't like it. It's really hard to follow what is going on with groovy. That is why I moved it to java.

[dbyron-sf]

OK. I suppose in some future we'll change GCEUtil to java too.

[edgarulg]

yes, that is the plan

[jasonmcintosh]

get 0 - just the one? NOT checked old code... but we're streaming below which may mean multiple zones...