A client/server helper wrapper for endpoints in Go.

go/src/infra/gae/epservice/epservice.go

Index: go/src/infra/gae/epservice/epservice.go
diff --git a/go/src/infra/gae/epservice/epservice.go b/go/src/infra/gae/epservice/epservice.go
new file mode 100644
index 0000000000000000000000000000000000000000..8d46ae4a120dafe55b66d3053f69b418e21bd29b
--- /dev/null
+++ b/go/src/infra/gae/epservice/epservice.go
@@ -0,0 +1,232 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// EPService will run a local appengine service with all of the endpoint
+// services under this directory. The tool assumes that:
+//   * goapp exists in PATH (and understands all the import paths in the
+//     defined services)
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"os/signal"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"sync"
+	"text/template"
+	"time"
+
+	"infra/libs/jsutil"
+)
+
+var (
+	clearDatastore      = flag.Bool("clear_datastore", false, "if set, clear the datastore.")
+	leak                = flag.Bool("leak", false, "if set, leak the temporary directory.")
+	verbose             = flag.Bool("verbose", false, "if set, print skipped packages.")
+	servicePackagesBase = flag.String("base", "infra",
+		"base Go package to walk to find service definitions.")
+)
+
+var serviceScript = `{{define "go"}}
+// DO NOT EDIT
+// Auto-generated by infra/gae/epservice
+// {{.Timestamp}}
+
+package main
+
+import (
+	"fmt"
+
+{{range $idx, $pkg := .Pkgs}}
+	pkg{{$idx}} "{{$pkg.Imp}}"{{end}}
+
+	"github.com/GoogleCloudPlatform/go-endpoints/endpoints"
+)
+
+func init() {
+	var err error
+	server := endpoints.NewServer("")
+
+	{{range $idx, $pkg := .Pkgs }}
+	err = pkg{{$idx}}.RegisterEndpointsService(server)
+	if err != nil {
+		panic(fmt.Errorf("Error while registering service {{$pkg}}: %s", err))
+	}
+	{{end}}
+
+	server.HandleHTTP(nil)
+}
+{{end}}
+`
+
+const appYaml = `{{define "yaml"}}
+# DO NOT EDIT
+# Auto-generated by infra/gae/epservice
+# {{.Timestamp}}
+
+application: epclient-tmp-app
+version: nope
+runtime: go
+api_version: go1
+
+handlers:
+- url: /.*
+  script: _go_app
+{{end}}
+`
+
+var templ = template.New("service")
+
+func init() {
+	template.Must(templ.Parse(serviceScript))
+	template.Must(templ.Parse(appYaml))
+}
+
+type templInput struct {
+	Pkgs      []Pkg
+	Timestamp time.Time
+}
+
+// Pkg holds the import and real filesystem paths of an endpoint service
+// package. It's exported merely for reflection purposes, since it's used
+// by text/template.
+type Pkg struct {
+	Imp string
+	Pth string
+}
+
+func boom(err error) {
+	if err != nil {
+		panic(err)
+	}
+}
+
+// NOTE: if you format your RegisterEndpointsService implementation like a bozo,
+// then this won't match. Don't do that.
+var reRegisterEndpointsService = regexp.MustCompile(
+	`\nfunc RegisterEndpointsService\(\w* \*\w*\.Server\) error {\n`)
+
+func getPkgs() []Pkg {
+	cmd := exec.Command("goapp", "list", "-json", filepath.Join(*servicePackagesBase+"..."))
+	d, err := cmd.Output()
+	boom(err)
+
+	d = []byte("[" + strings.Replace(string(d), "}\n{", "},{", -1) + "]")
+
+	js := interface{}(nil)
+	boom(json.Unmarshal(d, &js))
+
+	ret := []Pkg{}
+
+	type pkgOk struct {
+		p  Pkg
+		ok bool
+	}
+	pkgs := make(chan pkgOk)
+	wg := sync.WaitGroup{}
+
+	for _, m := range js.([]interface{}) {
+		pkg := Pkg{
+			jsutil.Get(m, "ImportPath").(string),
+			jsutil.Get(m, "Dir").(string),
+		}
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			paths, err := ioutil.ReadDir(pkg.Pth)
+			boom(err)
+
+			for _, f := range paths {
+				if !f.IsDir() && strings.HasSuffix(f.Name(), ".go") {
+					data, err := ioutil.ReadFile(filepath.Join(pkg.Pth, f.Name()))
+					boom(err)
+					if reRegisterEndpointsService.Match(data) {
+						pkgs <- pkgOk{pkg, true}
+						return
+					}
+				}
+			}
+			pkgs <- pkgOk{pkg, false}
+		}()
+	}
+	go func() {
+		wg.Wait()
+		close(pkgs)
+	}()
+
+	for p := range pkgs {
+		if !p.ok {
+			if *verbose {
+				fmt.Println("skipping package", p.p.Imp, "(it doesn't impliment RegisterEndpointsService?)")
+			}
+		} else {
+			fmt.Println("including package", p.p.Imp)
+			ret = append(ret, p.p)
+		}
+	}
+
+	return ret
+}
+
+func writeFiles(dir string, pkgs []Pkg) {
+	input := &templInput{pkgs, time.Now()}
+	for _, ext := range []string{"go", "yaml"} {
+		buf := &bytes.Buffer{}
+		boom(templ.ExecuteTemplate(buf, ext, input))
+		boom(ioutil.WriteFile(filepath.Join(dir, "app."+ext), buf.Bytes(), 0666))
+	}
+}
+
+func startServer(dir string) func() {
+	args := []string{"serve"}
+	if *clearDatastore {
+		args = append(args, "-clear_datastore")
+	}
+	args = append(args, dir)
+	server := exec.Command("goapp", args...)
+	server.SysProcAttr = serverStartParams
+	server.Stdout = os.Stdout
+	server.Stderr = os.Stderr
+	boom(server.Start())
+
+	return func() {
+		server.Process.Signal(os.Interrupt)
+		server.Wait()
+	}
+}
+
+func main() {
+	_, err := exec.LookPath("goapp")
+	if err != nil {
+		panic("goapp must be on your path")
+	}
+
+	flag.Parse()
+	pkgs := getPkgs()
+
+	dir, err := ioutil.TempDir("", "epservice_gen")
+	boom(err)
+	prefix := "LEAKING"
+	if !*leak {
+		prefix = "generating"
+		defer os.RemoveAll(dir)
+	}
+	fmt.Println(prefix, "files in:", dir)
+
+	writeFiles(dir, pkgs)
+
+	intC := make(chan os.Signal, 1)
+	signal.Notify(intC, os.Interrupt, os.Kill)
+
+	stop := startServer(dir)
+	defer stop()
+	<-intC
+}