fix #3334: adding basic support for server side apply

[shawkins]

Description

Adds basic support for server side apply via the additional patch type requested with #3334 - any higher level support for apply will be addressed under the other apply / createOrReplace issues.

This does ensure the fieldManager is set (fabric8 by default) and that the managedFields are cleared.

ServerSideIT shows the usage - typically all creates/updates would be done as server side apply. If you don't create the resource with server side apply any subsequent usage of server side apply will throw an exception - which you can workaround by including the force flag.

We may want to consider defaulting the user agent to fabric8 - if you create a resource using create, it will set the fieldManager to okhttp.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• Feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change
• Chore (non-breaking change which doesn't affect codebase;
  test, version modification, documentation, etc.)

Checklist

• Code contributed by me aligns with current project license: Apache 2.0
• I Added CHANGELOG entry regarding this change
• I have implemented unit tests to cover my changes
• I have added/updated the javadocs and other documentation accordingly
• No new bugs, code smells, etc. in SonarCloud report
• I tested my code in Kubernetes
• I tested my code in OpenShift

[shawkins]

On the UserAgent. It looks like we are looking for a property key of "fabric8-kubernetes-client/" + Version.clientVersion() - that seems more like it should be the default value if not set in the Config.

[manusa]

We may want to consider defaulting the user agent to fabric8 - if you create a resource using create, it will set the fieldManager to okhttp.

It looks like we are looking for a property key of "fabric8-kubernetes-client/" + Version.clientVersion() - that seems more like it should be the default value if not set in the Config.

Agree on the second, configurable value with default to fabric8-kubernetes-client/v$version

[shawkins]

Agree on the second, configurable value with default to fabric8-kubernetes-client/v$version

Applied that change as part of this pr - fabric8-kubernetes-client/$version

[rohanKanojia]

Thanks, please add some doc about this in CHEATSHEET as well. This has been requested multiple times

[sonarqubecloud]

SonarCloud Quality Gate failed.   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
4 Code Smells

42.1% Coverage
0.0% Duplication

[shawkins]

Thanks, please add some doc about this in CHEATSHEET as well. This has been requested multiple times

Sure. Also updated some other cheatsheet information related to creating clients and generic types.