Stop relying on -modfile to allow vendorization

The Makefile targets we use to build our tools rely on the `-modfile`
flag of the `go build` command.  Unfortunately, the golang build
toolchain doesn't respect the vendor directory relative to the `go.mod`
file specified by `-modfile`, and instead uses the vendor directory
relative to the current working directory.  Since each subdirectory in
this repository that contains a `go.mod` file needs to have its own
vendor directory in order to be built in vendorized scenarios, relying
on `-modfile` doesn't work.

The patch modifies the affected Makefile targets to instead change to
the directory of the tool being built instead of using the `-modfile`
flag.  This makes vendorization possible in downstream environments.

Finally, for consistency, we start building the kustomize tool in the
same way as controller-gen, and golangci-lint.

Makefile

@@ -18,7 +18,8 @@ COVER_PROFILE = cover.out
 BIN_DIR := bin
 
 CRD_OPTIONS ?= "crd:trivialVersions=false,allowDangerousTypes=true,crdVersions=v1"
-KUSTOMIZE ?= go run -modfile=hack/tools/go.mod sigs.k8s.io/kustomize/kustomize/v3
+KUSTOMIZE = tools/bin/kustomize
+CONTROLLER_GEN = tools/bin/controller-gen
 
 # See pkg/version.go for details
 SOURCE_GIT_COMMIT ?= $(shell git rev-parse --short HEAD)
@@ -83,7 +84,7 @@ unit-verbose: ## Run unit tests with verbose output
 linters: lint generate-check fmt-check
 
 tools/bin/golangci-lint: hack/tools/go.mod
-	go build -o $@ -modfile=$< github.com/golangci/golangci-lint/cmd/golangci-lint
+	cd hack/tools; go build -o $(abspath $@) github.com/golangci/golangci-lint/cmd/golangci-lint
 
 .PHONY: lint
 lint: tools/bin/golangci-lint
@@ -117,30 +118,33 @@ run-test-mode: generate fmt-check lint manifests ## Run against the configured K
 	go run -ldflags $(LDFLAGS) ./main.go -namespace=$(RUN_NAMESPACE) -dev -test-mode -webhook-port=0
 
 .PHONY: install
-install: manifests ## Install CRDs into a cluster
-	$(KUSTOMIZE) build config/crd | kubectl apply -f -
+install: $(KUSTOMIZE) manifests ## Install CRDs into a cluster
+	$< build config/crd | kubectl apply -f -
 
 .PHONY: uninstall
-uninstall: manifests ## Uninstall CRDs from a cluster
-	$(KUSTOMIZE) build config/crd | kubectl delete -f -
+uninstall: $(KUSTOMIZE) manifests ## Uninstall CRDs from a cluster
+	$< build config/crd | kubectl delete -f -
 
 .PHONY: deploy
-deploy: manifests ## Deploy controller in the configured Kubernetes cluster in ~/.kube/config
+deploy: $(KUSTOMIZE) manifests ## Deploy controller in the configured Kubernetes cluster in ~/.kube/config
 	cd config/manager && kustomize edit set image controller=${IMG}
-	$(KUSTOMIZE) build config/default | kubectl apply -f -
+	$< build config/default | kubectl apply -f -
 
-tools/bin/controller-gen: hack/tools/go.mod
-	go build -o $@ -modfile=$< sigs.k8s.io/controller-tools/cmd/controller-gen
+$(CONTROLLER_GEN): hack/tools/go.mod
+	cd hack/tools; go build -o $(abspath $@) sigs.k8s.io/controller-tools/cmd/controller-gen
+
+$(KUSTOMIZE): hack/tools/go.mod
+	cd hack/tools; go build -o $(abspath $@) sigs.k8s.io/kustomize/kustomize/v3
 
 .PHONY: manifests
-manifests: tools/bin/controller-gen ## Generate manifests e.g. CRD, RBAC etc.
-	cd apis; ../$< $(CRD_OPTIONS) rbac:roleName=manager-role webhook paths="./..." output:webhook:dir=../config/webhook/ output:crd:artifacts:config=../config/crd/bases
+manifests: $(CONTROLLER_GEN) $(KUSTOMIZE) ## Generate manifests e.g. CRD, RBAC etc.
+	cd apis; $(abspath $<) $(CRD_OPTIONS) rbac:roleName=manager-role webhook paths="./..." output:webhook:dir=../config/webhook/ output:crd:artifacts:config=../config/crd/bases
 	$< rbac:roleName=manager-role paths="./..." output:rbac:artifacts:config=config/rbac
 	$(KUSTOMIZE) build config/default > config/render/capm3.yaml
 
 .PHONY: generate
-generate: tools/bin/controller-gen ## Generate code
-	cd apis; ../$< object:headerFile="../hack/boilerplate.go.txt" paths="./..."
+generate: $(CONTROLLER_GEN) ## Generate code
+	cd apis; $(abspath $<) object:headerFile="../hack/boilerplate.go.txt" paths="./..."
 	$< object:headerFile="hack/boilerplate.go.txt" paths="./..."
 
 ## --------------------------------------
@@ -218,3 +222,5 @@ mod: ## Clean up go module settings
 	go mod verify
 	cd apis; go mod tidy
 	cd apis; go mod verify
+	cd hack/tools; go mod tidy
+	cd hack/tools; go mod verify

tools/deploy.sh

@@ -20,7 +20,7 @@ DEPLOY_BASIC_AUTH="${4,,}"
 DEPLOY_KEEPALIVED="${5,,}"
 MARIADB_HOST_IP="${MARIADB_HOST_IP:-"127.0.0.1"}"
 KUBECTL_ARGS="${KUBECTL_ARGS:-""}"
-KUSTOMIZE="go run -modfile=hack/tools/go.mod sigs.k8s.io/kustomize/kustomize/v3"
+KUSTOMIZE="tools/bin/kustomize"
 RESTART_CONTAINER_CERTIFICATE_UPDATED=${RESTART_CONTAINER_CERTIFICATE_UPDATED:-"false"}
 export NAMEPREFIX=${NAMEPREFIX:-"capm3"}
 
@@ -44,6 +44,8 @@ IRONIC_DEPLOY_FILES="${SCRIPTDIR}/ironic-deployment/basic-auth/default/auth.yaml
 	${SCRIPTDIR}/ironic-deployment/tls/keepalived/kustomization.yaml \
 	${SCRIPTDIR}/ironic-deployment/tls/keepalived/tls.yaml"
 
+make ${KUSTOMIZE}
+
 for DEPLOY_FILE in ${IRONIC_DEPLOY_FILES}; do
   cp "$DEPLOY_FILE" "$DEPLOY_FILE".bak
   # shellcheck disable=SC2094