Break cyclical dependency of generated template fs

For `fluxctl install`, we embed a set of templates in the fluxctl
binary by generating a fake filesystem as Go code
(pkg/install/generated_templates.gogen.go).

But the code that generates the fake filesystem also _depends_ on the
fake filesystem, since it does double duty as a program for generating
example manifests from those templates.

This leads to a problem: if anything has upset the generation process,
it's not possible to regenerate the files, since the generation tool
won't build.

A related problem, worked around elsewhere (#2473), is that it's easy
to introduce spurious differences in the generated code -- which,
since it's checked in -- means painful merges.

In general we don't care about the generated Go code, only about what
it produces. This commit removes it from git and from the uncommitted
change detection (`make check-generated`); and uses `fluxctl install`
to generate the example files, removing the need for the code
generating program to depend on the code it's generating.

Makefile

@@ -29,9 +29,11 @@ BUILD_DATE:=$(shell date -u +'%Y-%m-%dT%H:%M:%SZ')
 
 DOCS_PORT:=8000
 
+GENERATED_TEMPLATES_FILE=pkg/install/generated_templates.gogen.go
+
 all: $(GOBIN)/fluxctl $(GOBIN)/fluxd build/.flux.done
 
-release-bins:
+release-bins: $(GENERATED_TEMPLATES_FILE)
 	for arch in amd64; do \
 		for os in linux darwin windows; do \
 			CGO_ENABLED=0 GOOS=$$os GOARCH=$$arch go build -o "build/fluxctl_"$$os"_$$arch" $(LDFLAGS) -ldflags "-X main.version=$(shell ./docker/image-tag)" ./cmd/fluxctl/; \
@@ -51,7 +53,7 @@ clean:
 realclean: clean
 	rm -rf ./cache
 
-test: test/bin/helm test/bin/kubectl test/bin/kustomize
+test: test/bin/helm test/bin/kubectl test/bin/kustomize $(GENERATED_TEMPLATES_FILE)
 	PATH="${PWD}/bin:${PWD}/test/bin:${PATH}" go test ${TEST_FLAGS} $(shell go list ./... | grep -v "^github.com/fluxcd/flux/vendor" | sort -u)
 
 e2e: test/bin/helm test/bin/kubectl build/.flux.done
@@ -104,7 +106,7 @@ cache/%/helm-$(HELM_VERSION): docker/helm.version
 	tar -m -C ./cache -xzf cache/$*/helm-$(HELM_VERSION).tar.gz $*/helm
 	mv cache/$*/helm $@
 
-$(GOBIN)/fluxctl: $(FLUXCTL_DEPS)
+$(GOBIN)/fluxctl: $(FLUXCTL_DEPS) $(GENERATED_TEMPLATES_FILE)
 	go install ./cmd/fluxctl
 
 $(GOBIN)/fluxd: $(FLUXD_DEPS)
@@ -113,14 +115,19 @@ $(GOBIN)/fluxd: $(FLUXD_DEPS)
 integration-test: all
 	test/bin/test-flux
 
-generate-deploy: pkg/install/generated_templates.gogen.go
-	cd deploy && go run ../pkg/install/generate.go deploy
+generate-deploy: $(GOBIN)/fluxctl
+	$(GOBIN)/fluxctl install -o ./deploy \
+		--git-url git@github.com:fluxcd/flux-get-started \
+		--git-email flux@example.com \
+		--git-user 'Flux automation' \
+		--git-label flux \
+		--namespace flux
 
-pkg/install/generated_templates.gogen.go: pkg/install/templates/*
-	cd pkg/install && go run generate.go embedded-templates
+$(GENERATED_TEMPLATES_FILE): pkg/install/templates/*.tmpl pkg/install/generate.go
+	cd pkg/install && go run generate.go
 
-check-generated: generate-deploy pkg/install/generated_templates.gogen.go
-	git diff --exit-code -- integrations/apis integrations/client pkg/install/generated_templates.gogen.go
+check-generated: generate-deploy
+	git diff --exit-code -- deploy/
 
 build-docs:
 	@cd docs && docker build -t flux-docs .

deploy/flux-deployment.yaml

@@ -145,6 +145,9 @@ spec:
         # Include this if you want to restrict the manifests considered by flux
         # to those under the following relative paths in the git repository
         # - --git-path=subdir1,subdir2
+        - --git-label=flux
+        - --git-user=Flux automation
+        - --git-email=flux@example.com
 
         # Include these two to enable git commit signing
         # - --git-gpg-key-import=/root/gpg-import

pkg/install/generate.go

@@ -4,92 +4,28 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
 	"log"
 	"net/http"
 	"os"
-	"time"
 
 	"github.com/shurcooL/vfsgen"
-
-	"github.com/fluxcd/flux/pkg/install"
 )
 
 func main() {
 	usage := func() {
-		fmt.Fprintf(os.Stderr, "usage: %s {embedded-templates,deploy}\n", os.Args[0])
+		fmt.Fprintf(os.Stderr, "usage: %s\n", os.Args[0])
 		os.Exit(1)
 	}
-	if len(os.Args) != 2 {
+	if len(os.Args) != 1 {
 		usage()
 	}
-	switch os.Args[1] {
-	case "embedded-templates":
-		var fs http.FileSystem = modTimeFS{
-			fs: http.Dir("templates/"),
-		}
-		err := vfsgen.Generate(fs, vfsgen.Options{
-			Filename:     "generated_templates.gogen.go",
-			PackageName:  "install",
-			VariableName: "templates",
-		})
-		if err != nil {
-			log.Fatalln(err)
-		}
-	case "deploy":
-		params := install.TemplateParameters{
-			GitURL:    "git@github.com:fluxcd/flux-get-started",
-			GitBranch: "master",
-			Namespace: "flux",
-		}
-		manifests, err := install.FillInTemplates(params)
-		if err != nil {
-			fmt.Fprintf(os.Stderr, "error: failed to fill in templates: %s\n", err)
-			os.Exit(1)
-		}
-		for fileName, contents := range manifests {
-			if err := ioutil.WriteFile(fileName, contents, 0600); err != nil {
-				fmt.Fprintf(os.Stderr, "error: failed to write deploy file %s: %s\n", fileName, err)
-				os.Exit(1)
-			}
-		}
-
-	default:
-		usage()
-	}
-}
 
-// modTimeFS is a wrapper that rewrites all mod times to Unix epoch.
-// This is to ensure `generated_templates.gogen.go` only changes when
-// the folder and/or file contents change.
-type modTimeFS struct {
-	fs http.FileSystem
-}
-
-func (fs modTimeFS) Open(name string) (http.File, error) {
-	f, err := fs.fs.Open(name)
+	err := vfsgen.Generate(http.Dir("templates/"), vfsgen.Options{
+		Filename:     "generated_templates.gogen.go",
+		PackageName:  "install",
+		VariableName: "templates",
+	})
 	if err != nil {
-		return nil, err
+		log.Fatalln(err)
 	}
-	return modTimeFile{f}, nil
-}
-
-type modTimeFile struct {
-	http.File
-}
-
-func (f modTimeFile) Stat() (os.FileInfo, error) {
-	fi, err := f.File.Stat()
-	if err != nil {
-		return nil, err
-	}
-	return modTimeFileInfo{fi}, nil
-}
-
-type modTimeFileInfo struct {
-	os.FileInfo
-}
-
-func (modTimeFileInfo) ModTime() time.Time {
-	return time.Unix(0, 0)
 }