feat(build): introduces controller-gen scaffolding

[eoinfennessy]

These changes introduce the controller-gen tool and a make target to generate CRDs and DeepCopy methods. This target is added as a dependency of the build target, and runs only when changes are made to source files of the generated CRDs and methods.

Placeholder types for the MeshFederation kind have been added to verify generation.

[openshift-ci]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[jewertow]

How did you create MeshFederation resource? I was trying to add a resource with the following command:

kubebuilder create api --group federation --version v1alpha1 --kind ImportedService

but I got this error:

FATA failed to create API: unable to run pre-scaffold tasks of "base.go.kubebuilder.io/v4": cmd/main.go file should present in the root directory

Are you going to change cmd package in this PR?

[eoinfennessy]

How did you create MeshFederation resource?

I scaffolded a new project and API using kubebuilder, then copied the files in api/v1alpha1 and pasted them into their current location.

Are you going to change cmd package in this PR?

I wasn't intending to. I think enabling us to use controller-gen to generate code and CRDs is enough for this PR. The next step (a follow-up PR) will set up a simple controller for the MeshFederation resource. That work could include changing the project structure so that more APIs can be scaffolded using kubebuilder, but in my opinion this is not that important as creating each API is a one-time operation that can easily be achieved with a little copy-pasting, similar to what was done here.

[jewertow]

Ok, that works for me.

[bartoszmajsak]

I think we can simplify the entire generation to one command. You can bundle my suggestions to a single commit.

[bartoszmajsak]

Suggested change

	build: deps $(PROTOBUF_GEN) $(DEEP_COPY_GEN) $(CRD_GEN) ## Builds the project
	build: deps $(PROTOBUF_GEN) $(CRD_GEN) ## Builds the project

[bartoszmajsak]

Suggested change

	DEEP_COPY_DIR := $(PROJECT_DIR)/api/v1alpha1
	DEEP_COPY_SRC := $(shell find $(DEEP_COPY_DIR) -type f -not -name "*deepcopy.go")
	DEEP_COPY_GEN := $(DEEP_COPY_DIR)/zz_generated.deepcopy.go
	CRD_SRC_DIR := $(PROJECT_DIR)/api/v1alpha1
	CRD_SRC := $(shell find $(CRD_SRC_DIR) -type f -name "*.go")
	CRD_GEN_DIR := $(PROJECT_DIR)/chart/crds
	CRD_GEN := $(shell find $(CRD_GEN_DIR) -type f -name "*.yaml")
	CRD_SRC_DIR := $(PROJECT_DIR)/api/v1alpha1
	CRD_SRC := $(shell find $(CRD_SRC_DIR) -type f -name "*.go")
	CRD_GEN_DIR := $(PROJECT_DIR)/chart/crds
	CRD_GEN := $(shell find $(CRD_GEN_DIR) -type f -name "*.yaml")

[bartoszmajsak]

Moving forward we will also add webhooks, so having the entire generation as one command will be more efficient.

What we missed here is dependency to the controller-gen itself - if it's not present in the path it will now be automatically fetched.

Suggested change

	$(DEEP_COPY_GEN): $(DEEP_COPY_SRC) ## Generate code containing DeepCopy, DeepCopyInto, and DeepCopyObject method implementations.
	$(CONTROLLER_GEN) object:headerFile=$(LICENSE_FILE) paths="./..."
	$(CRD_GEN): $(CRD_SRC) ## Generate CustomResourceDefinition objects.
	$(CONTROLLER_GEN) crd paths="./..." output:crd:artifacts:config=chart/crds
	$(CRD_GEN): $(CRD_SRC) $(CONTROLLER_GEN) ## Generates CRDs and other controller-runtime scaffolding.
	$(CONTROLLER_GEN) paths="$(CRD_SRC_DIR)/..." \
	crd output:crd:artifacts:config="$(CRD_GEN_DIR)" \
	object:headerFile="$(LICENSE_FILE)"

[bartoszmajsak]

There's more to that btw (RBAC generation, kube-builder directives in controllers etc), but we can fine-tune it as we go.

[bartoszmajsak]

One other thing from the top of my head - if someone opens PR with code changes but forgets to regenerate CRDs and other stuff we will end up with misaligned artifacts, i.e. YAMLs will be behind. I will capture it as an issue.

[bartoszmajsak]

#125

[eoinfennessy]

Done.

[jewertow]

/retest

[bartoszmajsak]

Part of #148