fix(dist): load UI resources using embed

Makefile

@@ -58,12 +58,9 @@ docker: dep assets docker-${BINARY}
 
 assets: .jssrc .bindata
 
-.bindata: server/swagger.json canned/*.json protoboards/*.json dist/dist_gen.go
+.bindata: server/swagger.json canned/*.json protoboards/*.json $(UISOURCES)
 	@touch .bindata
 
-dist/dist_gen.go: $(UISOURCES)
-	go generate -x ./dist
-
 .jssrc: $(UISOURCES)
 	cd ui && yarn run clean && yarn run build
 	@touch .jssrc
@@ -142,7 +139,6 @@ clean:
 	cd ui && yarn run clean
 	rm -rf node_modules
 	cd ui && rm -rf node_modules
-	rm -f dist/dist_gen.go
 	@rm -f .godep .jsdep .jssrc .bindata
 
 ctags:

dist/dist.go

@@ -1,15 +1,9 @@
 package dist
 
-//go:generate go-bindata -o dist_gen.go -ignore '\.map|\.go' -pkg dist ../ui/build/... ../ui/package.json
-//go:generate go fmt dist_gen.go
-
 import (
-	"fmt"
 	"net/http"
-	"regexp"
-	"strings"
 
-	assetfs "github.com/elazarl/go-bindata-assetfs"
+	"github.com/influxdata/chronograf/ui"
 )
 
 // DebugAssets serves assets via a specified directory
@@ -23,92 +17,7 @@ func (d *DebugAssets) Handler() http.Handler {
 	return http.FileServer(NewDir(d.Dir, d.Default))
 }
 
-// BindataAssets serves assets from go-bindata, but, also serves Default if assent doesn't exist
-// This is to support single-page react-apps with its own router.
-type BindataAssets struct {
-	Prefix             string // Prefix is prepended to the http file request
-	Default            string // Default is the file to serve if the file is not found
-	DefaultContentType string // DefaultContentType is the content type of the default file
-}
-
-// Handler serves go-bindata using a go-bindata-assetfs façade
-func (b *BindataAssets) Handler() http.Handler {
-	return b
-}
-
-// addCacheHeaders requests an hour of Cache-Control and sets an ETag based on file size and modtime
-func (b *BindataAssets) addCacheHeaders(filename string, w http.ResponseWriter) error {
-	w.Header().Add("Cache-Control", "public, max-age=3600")
-
-	w.Header().Add("X-Frame-Options", "SAMEORIGIN")
-	w.Header().Add("X-XSS-Protection", "1; mode=block")
-	w.Header().Add("X-Content-Type-Options", "nosniff")
-	w.Header().Add("Content-Security-Policy", "script-src 'self'; object-src 'self'")
-
-	fi, err := AssetInfo(filename)
-	if err != nil {
-		return err
-	}
-
-	hour, minute, second := fi.ModTime().Clock()
-	etag := fmt.Sprintf(`"%d%d%d%d%d"`, fi.Size(), fi.ModTime().Day(), hour, minute, second)
-
-	w.Header().Set("ETag", etag)
-	return nil
-}
-
-// ServeHTTP wraps http.FileServer by returning a default asset if the asset
-// doesn't exist.  This supports single-page react-apps with its own
-// built-in router.  Additionally, we override the content-type if the
-// Default file is used.
-func (b *BindataAssets) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	// def wraps the assets to return the default file if the file doesn't exist
-	def := func(name string) ([]byte, error) {
-		// If the named asset exists, then return it directly.
-		octets, err := Asset(name)
-		if err != nil {
-			// If this is at / then we just error out so we can return a Directory
-			// This directory will then be redirected by go to the /index.html
-			if name == b.Prefix {
-				return nil, err
-			}
-			// If this is anything other than slash, we just return the default
-			// asset.  This default asset will handle the routing.
-			// Additionally, because we know we are returning the default asset,
-			// we need to set the default asset's content-type.
-			w.Header().Set("Content-Type", b.DefaultContentType)
-			if err := b.addCacheHeaders(b.Default, w); err != nil {
-				return nil, err
-			}
-			return Asset(b.Default)
-		}
-		if err := b.addCacheHeaders(name, w); err != nil {
-			return nil, err
-		}
-		// https://github.com/influxdata/chronograf/issues/5565
-		// workaround wrong .js content-type on windows
-		if strings.HasSuffix(name, ".js") {
-			w.Header().Set("Content-Type", "text/javascript")
-		}
-		return octets, nil
-	}
-	var dir http.FileSystem = &assetfs.AssetFS{
-		Asset:     def,
-		AssetDir:  AssetDir,
-		AssetInfo: AssetInfo,
-		Prefix:    b.Prefix,
-	}
-	http.FileServer(dir).ServeHTTP(w, r)
-}
-
-var re = regexp.MustCompile(`"version"\s*:\s*"(.*)"`)
-
 // GetVersion returns version of the packed assets
 func GetVersion() string {
-	if data, err := Asset("../ui/package.json"); err == nil {
+	return ui.GetVersion()
-		if matches := re.FindStringSubmatch(string(data)); matches != nil {
-			return matches[1]
-		}
-	}
-	return ""
 }

server/assets.go

@@ -5,19 +5,14 @@ import (
 
 	"github.com/influxdata/chronograf"
 	"github.com/influxdata/chronograf/dist"
+	"github.com/influxdata/chronograf/ui"
 )
 
 const (
-	// Dir is prefix of the assets in the bindata
-	Dir = "../ui/build"
-	// Default is the default item to load if 404
-	Default = "../ui/build/index.html"
 	// DebugDir is the prefix of the assets in development mode
 	DebugDir = "ui/build"
 	// DebugDefault is the default item to load if 404
 	DebugDefault = "ui/build/index.html"
-	// DefaultContentType is the content-type to return for the Default file
-	DefaultContentType = "text/html; charset=utf-8"
 )
 
 // AssetsOpts configures the asset middleware
@@ -37,11 +32,7 @@ func Assets(opts AssetsOpts) http.Handler {
 			Default: DebugDefault,
 		}
 	} else {
-		assets = &dist.BindataAssets{
+		assets = &ui.BindataAssets{}
-			Prefix:             Dir,
-			Default:            Default,
-			DefaultContentType: DefaultContentType,
-		}
 	}
 
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {

ui/dist.go

@@ -0,0 +1,126 @@
+package ui
+
+import (
+	"embed"
+	"fmt"
+	"io/fs"
+	"net/http"
+	"regexp"
+	"strings"
+)
+
+const (
+	// Default page to load (upon a miss)
+	DefaultPage = "index.html"
+	// DefaultPageContentType is the content-type of the DefaultPage
+	DefaultPageContentType = "text/html; charset=utf-8"
+)
+
+//go:embed build/*
+var embeddedFS embed.FS
+var buildDir fs.FS
+
+//go:embed package.json
+var packageJson string
+var version string
+
+// init initializes version and buildDir file system
+func init() {
+	// parse version
+	version = ""
+	re := regexp.MustCompile(`"version"\s*:\s*"(.*)"`)
+	if matches := re.FindStringSubmatch(packageJson); matches != nil {
+		version = matches[1]
+	}
+	// initialize buildDir and default file
+	var err error
+	if buildDir, err = fs.Sub(embeddedFS, "build"); err != nil {
+		panic("no ui/build directory found!")
+	}
+}
+
+// BindataAssets serves embedded ui assets and also serves its index.html by default
+// in order to support single-page react-apps with its own router.
+type BindataAssets struct {
+}
+
+// fsImpl is a s imple fs.FS implementation that uses the supplied OpenFn function
+type fsImpl struct {
+	openFn func(path string) (fs.File, error)
+}
+
+func (fs *fsImpl) Open(path string) (fs.File, error) {
+	return fs.openFn(path)
+}
+
+// Handler returns HTTP handler that serves embedded data
+func (b *BindataAssets) Handler() http.Handler {
+	return b
+}
+
+// addCacheHeaders requests an hour of Cache-Control and sets an ETag based on file size and modtime
+func addCacheHeaders(file fs.File, headers http.Header) error {
+	fi, err := file.Stat()
+	if err == nil {
+		headers.Add("Cache-Control", "public, max-age=3600")
+
+		headers.Add("X-Frame-Options", "SAMEORIGIN")
+		headers.Add("X-XSS-Protection", "1; mode=block")
+		headers.Add("X-Content-Type-Options", "nosniff")
+		headers.Add("Content-Security-Policy", "script-src 'self'; object-src 'self'")
+
+		hour, minute, second := fi.ModTime().Clock()
+		etag := fmt.Sprintf(`"%d%d%d%d%d"`, fi.Size(), fi.ModTime().Day(), hour, minute, second)
+
+		headers.Set("ETag", etag)
+	}
+	return err
+}
+
+// ServeHTTP wraps http.FileServer by returning a default asset if the asset
+// doesn't exist.  This supports single-page react-apps with its own
+// built-in router.  Additionally, we override the content-type if the
+// Default file is used.
+func (b *BindataAssets) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	// openFn wraps buidDir.Open in order to setup default HTTP headers
+	// it also returns the default file if the file doesn't exist
+	openFn := func(name string) (fs.File, error) {
+		// If the named asset exists, then return it directly.
+		file, err := buildDir.Open(name)
+		if err != nil {
+			// If this is at / then we just error out so we can return a Directory
+			// This directory will then be redirected by go to the /index.html
+			if name == "/" || name == "." {
+				return nil, err
+			}
+			// If this is anything other than slash, we just return the default
+			// asset.  This default asset will handle the routing.
+			// Additionally, because we know we are returning the default asset,
+			// we need to set the default asset's content-type.
+			w.Header().Set("Content-Type", DefaultPageContentType)
+			defaultFile, err := buildDir.Open(DefaultPage)
+			if err != nil {
+				return nil, err
+			}
+			file = defaultFile
+		}
+		if err := addCacheHeaders(file, w.Header()); err != nil {
+			return nil, err
+		}
+		// https://github.com/influxdata/chronograf/issues/5565
+		// workaround wrong .js content-type on windows
+		if strings.HasSuffix(name, ".js") {
+			w.Header().Set("Content-Type", "text/javascript")
+		}
+		return file, nil
+	}
+	var fs fs.FS = &fsImpl{
+		openFn: openFn,
+	}
+	http.FileServer(http.FS(fs)).ServeHTTP(w, r)
+}
+
+// GetVersion returns version of the packed assets
+func GetVersion() string {
+	return version
+}