Re-add the v1alpha1 API and implement conversion code

[amisevsk]

This PR should be reviewed commit-by-commit

What does this PR do?

• Re-add the go files defining the v1alpha1 API (this tag) to the current repo
• Implement conversion between v1alpha2 and v1alpha1 as much as possible (see below) according to the standard k8s spec (doc)
  • v1alpha2 is defined as the hub and the storage version.
• Add tests for conversion code.
• Regenerate files where appropriate to include v1alpha1.

Note that the general k8s requirement is that all CRD versions are safely round-trippable, meaning we can freely convert between them with no loss of information. This is not possible for DevWorkspaces due to some removals in v1alpha2 (e.g. removing custom commands and components from parents). I've added a few fields to the v1alpha1 spec where appropriate, so that we're mostly able to safely convert v1alpha2 -> v1alpha1 -> v1alpha2 without issue (the exception is sparseCheckoutDirs on Projects)

The general approach in this PR is to rely on yaml marshalling and unmarshalling. Otherwise a huge amount of code is required. Attempting to use conversion-gen results in an auto-generated file that's 2500 lines long, and still doesn't implement the bulk of the conversion.

Is your PR tested? Consider putting some instruction how to test your changes

This PR includes tests where the general structure is to fuzz a v1alpha1 struct, convert it v1alpha1 -> v1alpha2 -> v1alpha1 and check that it is unchanged.

I've also included a simple benchmark for conversion. Using a mostly-filled devworkspace, conversion takes around 8ms 5ms on my machine.

To test the code, use

go test ./pkg/apis/workspaces/v1alpha1 --count=1 -test.v

To run the benchmark,

go test ./pkg/apis/workspaces/v1alpha1 -bench=. -run=none -test.v

Additional Info

Summary of additions to v1alpha1 in this PR:

• Remove duplicate memoryLimit from Container components. (c.f. clean up the extra memoryLimit defined in containerComponent #175) -- the duplication actually breaks deserialization
• Add Keyed implementation to CustomComponent
• Add StarterProjects to Parent

With the additions above, the differences between v1alpha1 and v1alpha2 are

• Keys (ID/Name) are generally moved a level up in the yaml structure for Components, Commands, etc.
• Custom Components are removed from Plugin components and Parent
• Custom Commands are removed from Plugin components and Parent.
• Structure of Projects is significantly changed:
  • Custom project type is removed from Parent
  • sparseCheckoutDir is moved a level up and converted to a list. Since with v1alpha2, we can have multiple
  • For starter projects, clonePath and sparseCheckoutDir are removed; subDir is added. For compatibility, I use subDir to hold the value of sparseCheckoutDir.

A summary of differences can be found in this diff

[maysunfaisal]

@amisevsk curious as to why we're adding this and the conversion back when we didnt release during v1alpha1 :)

[amisevsk]

@maysunfaisal Because the Web Terminal Operator is released (you can grab it on crc now) and uses the v1alpha1 API.

[sleshchenko]

Good job. Nothing meaningful to add )
It was pretty craftily to use yaml marshaling to reduce our code for converting, as we see it's fast enough to proceed with.

[amisevsk]

Rebased on master to resolve a conflict with #211

[amisevsk]

Fixed a rare test flake when gofuzz would generate a map[string]string with the yaml merge key (<<), breaking yaml serialization/deserialization.

[amisevsk]

As suggested by @davidfestal, I've updated conversion to use json as an intermediate representation, since the yaml package we use converts between yaml and json as an intermediate step.

[JPinkney]

LGTM

[davidfestal]

Approved, but you will have to rebase the PR on master since I merged PR #214, so that endpoint attributes should be updated from string[string]string to Attributes.

[openshift-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: amisevsk, davidfestal, JPinkney, sleshchenko
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[openshift-ci-robot]

New changes are detected. LGTM label has been removed.

[amisevsk]

Rebased on master to include changes from #214

I had to write some additional conversion code, since #214 moves attributes on commands up a level (from e.g. command.Exec.Attributes to command.Attributes. It also removes attributes from Parent commands, which is not reflected in the test cases.

In the general case, no changes were needed for converting attributes in other cases.

[amisevsk]

Merging this PR as it's been two weeks; if any further issues are brought forward I'll fix them separately.

[sleshchenko]

🎉