Migrate from go-bindata to vfsgen

Makefile

@@ -20,15 +20,6 @@ STATICCHECK_IGNORE = \
 
 DOCKER_IMAGE_NAME ?= pushgateway
 
-ifdef DEBUG
-	bindata_flags = -debug
-endif
-
 assets:
 	@echo ">> writing assets"
-	@$(GO) get -u github.com/jteeuwen/go-bindata/...
-	@go-bindata $(bindata_flags) -prefix=resources resources/...
-
-style:
-	@echo ">> checking code style"
-	! $(GOFMT) -d $$(find . -path ./vendor -prune -o -path ./bindata.go -prune -o -name '*.go' -print) | grep '^'
+	@cd $(PREFIX)/asset && $(GO) generate && $(GOFMT) -w assets_vfsdata.go

README.md

@@ -311,10 +311,10 @@ contrast to how the deprecated form of the path is treated during pushing).
 
 The normal binary embeds the web files in the `resources` directory.
 For development purposes, it is handy to have a running binary use
-those files directly (so that you can see the effect of changes
-immediately). To switch to direct usage, type `DEBUG=1 make assets`
-just before compiling the binary. Switch back to "normal" mode by
-typing `make assets`.
+those files directly (so that you can see the effect of changes immediately).
+To switch to direct usage, add `-tags dev` to the `flags` entry in
+`.promu.yml`, and then `make build`. Switch back to "normal" mode by
+reverting the changes to `.promu.yml` and typing `make assets`.
 
 ##  Contributing
 

asset/asset.go

@@ -0,0 +1,33 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build dev
+
+package asset
+
+import (
+	"go/build"
+	"log"
+	"net/http"
+)
+
+func importPathToDir(importPath string) string {
+	p, err := build.Import(importPath, "", build.FindOnly)
+	if err != nil {
+		log.Fatalln(err)
+	}
+	return p.Dir
+}
+
+// Assets contains the project's assets.
+var Assets http.FileSystem = http.Dir(importPathToDir("github.com/prometheus/pushgateway/resources"))

asset/asset_generate.go

@@ -0,0 +1,34 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build ignore
+
+package main
+
+import (
+	"log"
+
+	"github.com/prometheus/pushgateway/asset"
+	"github.com/shurcooL/vfsgen"
+)
+
+func main() {
+	err := vfsgen.Generate(asset.Assets, vfsgen.Options{
+		PackageName:  "asset",
+		BuildTags:    "!dev",
+		VariableName: "Assets",
+	})
+	if err != nil {
+		log.Fatalln(err)
+	}
+}

asset/doc.go

@@ -0,0 +1,22 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package asset provides the assets via a virtual filesystem.
+package asset
+
+import (
+	// The blank import is to make govendor happy.
+	_ "github.com/shurcooL/vfsgen"
+)
+
+//go:generate go run -tags=dev asset_generate.go

handler/status.go

@@ -17,6 +17,7 @@ import (
 	"fmt"
 	"html"
 	"html/template"
+	"io/ioutil"
 	"net/http"
 	"strconv"
 	"time"
@@ -48,7 +49,7 @@ func (data) FormatTimestamp(ts int64) string {
 // Status serves the status page.
 func Status(
 	ms storage.MetricStore,
-	assetFunc func(string) ([]byte, error),
+	root http.FileSystem,
 	flags map[string]string,
 ) func(http.ResponseWriter, *http.Request) {
 	birth := time.Now()
@@ -59,12 +60,19 @@ func Status(
 				return strconv.FormatFloat(f, 'f', -1, 64)
 			},
 		})
-		tpl, err := assetFunc("template.html")
+		f, err := root.Open("template.html")
 		if err != nil {
 			http.Error(w, err.Error(), http.StatusInternalServerError)
 			log.Errorf("Error loading template.html, %v", err.Error())
 			return
 		}
+		defer f.Close()
+		tpl, err := ioutil.ReadAll(f)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			log.Errorf("Error reading template.html, %v", err.Error())
+			return
+		}
 		_, err = t.Parse(string(tpl))
 		if err != nil {
 			http.Error(w, err.Error(), http.StatusInternalServerError)

main.go

@@ -25,7 +25,6 @@ import (
 	"syscall"
 	"time"
 
-	"github.com/elazarl/go-bindata-assetfs"
 	"github.com/julienschmidt/httprouter"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/log"
@@ -34,6 +33,7 @@ import (
 
 	dto "github.com/prometheus/client_model/go"
 
+	"github.com/prometheus/pushgateway/asset"
 	"github.com/prometheus/pushgateway/handler"
 	"github.com/prometheus/pushgateway/storage"
 )
@@ -105,16 +105,8 @@ func main() {
 
 	r.Handler("GET", *routePrefix+"/static/*filepath", prometheus.InstrumentHandler(
 		"static",
-		http.FileServer(
-			&assetfs.AssetFS{
-				Asset: func(name string) ([]byte, error) {
-					path := name[len(*routePrefix):]
-					return Asset(path)
-				},
-				AssetDir: AssetDir, AssetInfo: AssetInfo},
-		),
-	))
-	statusHandler := prometheus.InstrumentHandlerFunc("status", handler.Status(ms, Asset, flags))
+		http.FileServer(asset.Assets)))
+	statusHandler := prometheus.InstrumentHandlerFunc("status", handler.Status(ms, asset.Assets, flags))
 	r.Handler("GET", *routePrefix+"/status", statusHandler)
 	r.Handler("GET", *routePrefix+"/", statusHandler)