Makefile, webhook: add run-nowebhook (opendatahub-io#1286)

Make it possible to compile operator without webhook enabled (with
-tags nowebhook). Create a stub webhook.Init() function for that.

Add run-nowebhook target to run webhook locally. It requires
`make install` to be executed on the cluster beforehand.

Since it repeats `make run`, move the command to a variable.
Also use variable RUN_ARGS for operator arguments. It makes it
possible to override them from the command line.

In VSCode it is possible to debug it with the following example
launch.json configuration:

```
        {
            "name": "Debug Operator No Webhook",
            "type": "go",
            "request": "launch",
            "mode": "debug",
            "program": "main.go",
            "buildFlags": [
                "-tags", "nowebhook"
            ],
            "env": {
                "OPERATOR_NAMESPACE": "opendatahub-operator-system",
                "DEFAULT_MANIFESTS_PATH": "./opt/manifests"
            },
            "args": [
                "--log-mode=devel"
            ],
            "cwd": "${workspaceFolder}",
        }
```

Signed-off-by: Yauheni Kaliuta <[email protected]>

Makefile

@@ -180,9 +180,16 @@ api-docs: crd-ref-docs ## Creates API docs using https://github.com/elastic/crd-
 build: generate fmt vet ## Build manager binary.
 	go build -o bin/manager main.go
 
+RUN_ARGS = --log-mode=devel
+GO_RUN_MAIN = OPERATOR_NAMESPACE=$(OPERATOR_NAMESPACE) DEFAULT_MANIFESTS_PATH=$(DEFAULT_MANIFESTS_PATH) go run $(GO_RUN_ARGS) ./main.go $(RUN_ARGS)
 .PHONY: run
 run: manifests generate fmt vet ## Run a controller from your host.
-	OPERATOR_NAMESPACE=$(OPERATOR_NAMESPACE) DEFAULT_MANIFESTS_PATH=${DEFAULT_MANIFESTS_PATH} go run ./main.go --log-mode=devel
+	$(GO_RUN_MAIN)
+
+.PHONY: run-nowebhook
+run-nowebhook: GO_RUN_ARGS += -tags nowebhook
+run-nowebhook: manifests generate fmt vet ## Run a controller from your host without webhook enabled
+	$(GO_RUN_MAIN)
 
 .PHONY: image-build
 image-build: # unit-test ## Build image with the manager.

controllers/webhook/nowebhook.go

@@ -0,0 +1,7 @@
+//go:build nowebhook
+
+package webhook
+
+import ctrl "sigs.k8s.io/controller-runtime"
+
+func Init(mgr ctrl.Manager) {}

controllers/webhook/webhook.go

@@ -1,3 +1,5 @@
+//go:build !nowebhook
+
 /*
 Copyright 2023.