Generate CRDs for APIs (#471)

- CRDs are now generated with `make generate` with `controller-gen` from
`controller-runtime`.
- Removed unneeded `MachineTemplate`.
- Use `k8s.io/api/autoscaling/v1.Scale` instead of home-brew copy.
- Split all versioned APIs into separate `go` files for better code
navigation.

Author: Martin Vladev

Makefile

@@ -20,6 +20,13 @@ CONTROL_NAMESPACE  := default
 CONTROL_KUBECONFIG := dev/target-kubeconfig.yaml
 TARGET_KUBECONFIG  := dev/target-kubeconfig.yaml
 
+# Get the currently used golang install path (in GOPATH/bin, unless GOBIN is set)
+ifeq (,$(shell go env GOBIN))
+GOBIN=$(shell go env GOPATH)/bin
+else
+GOBIN=$(shell go env GOBIN)
+endif
+
 #########################################
 # Rules for local development scenarios #
 #########################################
@@ -120,3 +127,25 @@ show-coverage:
 test-clean:
 	@find . -name "*.coverprofile" -type f -delete
 	@rm -f $(COVERPROFILE)
+
+generate: controller-gen
+	$(CONTROLLER_GEN) crd paths=./pkg/apis/machine/v1alpha1... output:crd:dir=kubernetes/crds output:stdout
+	@./hack/generate-code
+
+# find or download controller-gen
+# download controller-gen if necessary
+.PHONY: controller-gen
+controller-gen:
+ifeq (, $(shell which controller-gen))
+	@{ \
+	set -e ;\
+	CONTROLLER_GEN_TMP_DIR=$$(mktemp -d) ;\
+	cd $$CONTROLLER_GEN_TMP_DIR ;\
+	go mod init tmp ;\
+	go get sigs.k8s.io/controller-tools/cmd/controller-gen@v0.3.0 ;\
+	rm -rf $$CONTROLLER_GEN_TMP_DIR ;\
+	}
+CONTROLLER_GEN=$(GOBIN)/controller-gen
+else
+CONTROLLER_GEN=$(shell which controller-gen)
+endif