go vendor

vendor/github.com/revel/cmd/harness/harness.go

@@ -0,0 +1,285 @@
+// Copyright (c) 2012-2016 The Revel Framework Authors, All rights reserved.
+// Revel Framework source code and usage is governed by a MIT style
+// license that can be found in the LICENSE file.
+
+// Package harness for a Revel Framework.
+//
+// It has a following responsibilities:
+// 1. Parse the user program, generating a main.go file that registers
+//    controller classes and starts the user's server.
+// 2. Build and run the user program.  Show compile errors.
+// 3. Monitor the user source and re-build / restart the program when necessary.
+//
+// Source files are generated in the app/tmp directory.
+package harness
+
+import (
+	"crypto/tls"
+	"fmt"
+	"go/build"
+	"io"
+	"net"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+	"os"
+	"os/signal"
+	"path/filepath"
+	"strings"
+	"sync/atomic"
+
+	"github.com/revel/revel"
+	"sync"
+)
+
+var (
+	doNotWatch = []string{"tmp", "views", "routes"}
+
+	lastRequestHadError int32
+)
+
+// Harness reverse proxies requests to the application server.
+// It builds / runs / rebuilds / restarts the server when code is changed.
+type Harness struct {
+	app        *App
+	serverHost string
+	port       int
+	proxy      *httputil.ReverseProxy
+	watcher    *revel.Watcher
+	mutex      *sync.Mutex
+}
+
+func renderError(iw http.ResponseWriter, ir *http.Request, err error) {
+	context := revel.NewGoContext(nil)
+	context.Request.SetRequest(ir)
+	context.Response.SetResponse(iw)
+	c := revel.NewController(context)
+	c.RenderError(err).Apply(c.Request, c.Response)
+}
+
+// ServeHTTP handles all requests.
+// It checks for changes to app, rebuilds if necessary, and forwards the request.
+func (h *Harness) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	// Don't rebuild the app for favicon requests.
+	if lastRequestHadError > 0 && r.URL.Path == "/favicon.ico" {
+		return
+	}
+
+	// Flush any change events and rebuild app if necessary.
+	// Render an error page if the rebuild / restart failed.
+	err := h.watcher.Notify()
+	if err != nil {
+		// In a thread safe manner update the flag so that a request for
+		// /favicon.ico does not trigger a rebuild
+		atomic.CompareAndSwapInt32(&lastRequestHadError, 0, 1)
+		renderError(w, r, err)
+		return
+	}
+
+	// In a thread safe manner update the flag so that a request for
+	// /favicon.ico is allowed
+	atomic.CompareAndSwapInt32(&lastRequestHadError, 1, 0)
+
+	// Reverse proxy the request.
+	// (Need special code for websockets, courtesy of bradfitz)
+	if strings.EqualFold(r.Header.Get("Upgrade"), "websocket") {
+		proxyWebsocket(w, r, h.serverHost)
+	} else {
+		h.proxy.ServeHTTP(w, r)
+	}
+}
+
+// NewHarness method returns a reverse proxy that forwards requests
+// to the given port.
+func NewHarness() *Harness {
+	// Get a template loader to render errors.
+	// Prefer the app's views/errors directory, and fall back to the stock error pages.
+	revel.MainTemplateLoader = revel.NewTemplateLoader(
+		[]string{filepath.Join(revel.RevelPath, "templates")})
+	if err := revel.MainTemplateLoader.Refresh(); err != nil {
+		revel.RevelLog.Error("Template loader error", "error", err)
+	}
+
+	addr := revel.HTTPAddr
+	port := revel.Config.IntDefault("harness.port", 0)
+	scheme := "http"
+	if revel.HTTPSsl {
+		scheme = "https"
+	}
+
+	// If the server is running on the wildcard address, use "localhost"
+	if addr == "" {
+		addr = "localhost"
+	}
+
+	if port == 0 {
+		port = getFreePort()
+	}
+
+	serverURL, _ := url.ParseRequestURI(fmt.Sprintf(scheme+"://%s:%d", addr, port))
+
+	serverHarness := &Harness{
+		port:       port,
+		serverHost: serverURL.String()[len(scheme+"://"):],
+		proxy:      httputil.NewSingleHostReverseProxy(serverURL),
+		mutex:      &sync.Mutex{},
+	}
+
+	if revel.HTTPSsl {
+		serverHarness.proxy.Transport = &http.Transport{
+			TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
+		}
+	}
+	return serverHarness
+}
+
+// Refresh method rebuilds the Revel application and run it on the given port.
+func (h *Harness) Refresh() (err *revel.Error) {
+	// Allow only one thread to rebuild the process
+	h.mutex.Lock()
+	defer h.mutex.Unlock()
+
+	if h.app != nil {
+		h.app.Kill()
+	}
+
+	revel.RevelLog.Debug("Rebuild Called")
+	h.app, err = Build()
+	if err != nil {
+		return
+	}
+
+	h.app.Port = h.port
+	if err2 := h.app.Cmd().Start(); err2 != nil {
+		return &revel.Error{
+			Title:       "App failed to start up",
+			Description: err2.Error(),
+		}
+	}
+
+	return
+}
+
+// WatchDir method returns false to file matches with doNotWatch
+// otheriwse true
+func (h *Harness) WatchDir(info os.FileInfo) bool {
+	return !revel.ContainsString(doNotWatch, info.Name())
+}
+
+// WatchFile method returns true given filename HasSuffix of ".go"
+// otheriwse false - implements revel.DiscerningListener
+func (h *Harness) WatchFile(filename string) bool {
+	return strings.HasSuffix(filename, ".go")
+}
+
+// Run the harness, which listens for requests and proxies them to the app
+// server, which it runs and rebuilds as necessary.
+func (h *Harness) Run() {
+	var paths []string
+	if revel.Config.BoolDefault("watch.gopath", false) {
+		gopaths := filepath.SplitList(build.Default.GOPATH)
+		paths = append(paths, gopaths...)
+	}
+	paths = append(paths, revel.CodePaths...)
+	h.watcher = revel.NewWatcher()
+	h.watcher.Listen(h, paths...)
+	h.watcher.Notify()
+
+	go func() {
+		addr := fmt.Sprintf("%s:%d", revel.HTTPAddr, revel.HTTPPort)
+		revel.RevelLog.Infof("Listening on %s", addr)
+
+		var err error
+		if revel.HTTPSsl {
+			err = http.ListenAndServeTLS(
+				addr,
+				revel.HTTPSslCert,
+				revel.HTTPSslKey,
+				h)
+		} else {
+			err = http.ListenAndServe(addr, h)
+		}
+		if err != nil {
+			revel.RevelLog.Error("Failed to start reverse proxy:", "error", err)
+		}
+	}()
+
+	// Kill the app on signal.
+	ch := make(chan os.Signal)
+	signal.Notify(ch, os.Interrupt, os.Kill)
+	<-ch
+	if h.app != nil {
+		h.app.Kill()
+	}
+	os.Exit(1)
+}
+
+// Find an unused port
+func getFreePort() (port int) {
+	conn, err := net.Listen("tcp", ":0")
+	if err != nil {
+		revel.RevelLog.Fatal("Unable to fetch a freee port address", "error", err)
+	}
+
+	port = conn.Addr().(*net.TCPAddr).Port
+	err = conn.Close()
+	if err != nil {
+		revel.RevelLog.Fatal("Unable to close port", "error", err)
+	}
+	return port
+}
+
+// proxyWebsocket copies data between websocket client and server until one side
+// closes the connection.  (ReverseProxy doesn't work with websocket requests.)
+func proxyWebsocket(w http.ResponseWriter, r *http.Request, host string) {
+	var (
+		d   net.Conn
+		err error
+	)
+	if revel.HTTPSsl {
+		// since this proxy isn't used in production,
+		// it's OK to set InsecureSkipVerify to true
+		// no need to add another configuration option.
+		d, err = tls.Dial("tcp", host, &tls.Config{InsecureSkipVerify: true})
+	} else {
+		d, err = net.Dial("tcp", host)
+	}
+	if err != nil {
+		http.Error(w, "Error contacting backend server.", 500)
+		revel.RevelLog.Error("Error dialing websocket backend ", "host", host, "error", err)
+		return
+	}
+	hj, ok := w.(http.Hijacker)
+	if !ok {
+		http.Error(w, "Not a hijacker?", 500)
+		return
+	}
+	nc, _, err := hj.Hijack()
+	if err != nil {
+		revel.RevelLog.Error("Hijack error", "error", err)
+		return
+	}
+	defer func() {
+		if err = nc.Close(); err != nil {
+			revel.RevelLog.Error("Connection close error", "error", err)
+		}
+		if err = d.Close(); err != nil {
+			revel.RevelLog.Error("Dial close error", "error", err)
+		}
+	}()
+
+	err = r.Write(d)
+	if err != nil {
+		revel.RevelLog.Error("Error copying request to target", "error", err)
+		return
+	}
+
+	errc := make(chan error, 2)
+	cp := func(dst io.Writer, src io.Reader) {
+		_, err := io.Copy(dst, src)
+		errc <- err
+	}
+	go cp(d, nc)
+	go cp(nc, d)
+	<-errc
+}