Add android_run_app.go

Launches an app, pipes its output, and exits when the app exits.

Loosely based on the old buildbot code in python:
https://skia.googlesource.com/buildbot/+/ac0663c599a443a4958c8cad5aefd25eb09eff58/slave/skia_slave_scripts/utils/android_utils.py

BUG=skia:4093

Review URL: https://codereview.chromium.org/1256353002

platform_tools/android/bin/android_run_app.go

@@ -0,0 +1,248 @@
+// Copyright (c) 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.
+
+/*
+	Run a Skia app to completion, piping the log to stdout.
+*/
+
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"os/signal"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/skia-dev/glog"
+	"go.skia.org/infra/go/common"
+)
+
+const (
+	COM_SKIA = "com.skia"
+)
+
+var (
+	adbPath = flag.String("adb", "", "Path to the ADB executable.")
+	app     = flag.String("app", "VisualBench", "Name of the app to run.")
+	serial  = flag.String("s", "", "Serial number for the Android device to use.")
+)
+
+// Struct used for running ADB commands.
+type ADB struct {
+	path   string
+	serial string
+}
+
+// ADBFromFlags returns an ADB instance based on flags passed to the program.
+func ADBFromFlags() *ADB {
+	rv := &ADB{
+		path:   *adbPath,
+		serial: *serial,
+	}
+	if rv.path == "" {
+		rv.path = "adb"
+	}
+	return rv
+}
+
+// Cmd creates an exec.Cmd object for the given ADB command.
+func (adb *ADB) Cmd(log bool, args ...string) *exec.Cmd {
+	cmd := []string{}
+	if adb.serial != "" {
+		cmd = append(cmd, "-s", adb.serial)
+	}
+	cmd = append(cmd, args...)
+	if log {
+		glog.Infof("Exec `%s %s`", adb.path, strings.Join(cmd, " "))
+	}
+	return exec.Command(adb.path, cmd...)
+}
+
+// KillSkia kills any running process.
+func (adb *ADB) Kill(proc string) error {
+	return adb.Cmd(false, "shell", "am", "force-stop", proc).Run()
+}
+
+// PollSkia checks to see if the given process is running. If so, return the pid, otherwise return -1.
+func (adb *ADB) Poll(proc string) (int64, error) {
+	output, err := adb.Cmd(false, "shell", "ps").Output()
+	if err != nil {
+		return -1, fmt.Errorf("Failed to check the running processes on the device: %v", err)
+	}
+	for _, line := range strings.Split(string(output), "\n") {
+		if strings.Contains(line, proc) {
+			fields := strings.Fields(line)
+			pid, err := strconv.ParseInt(fields[1], 10, 32)
+			if err != nil {
+				return -1, fmt.Errorf("Failed to parse \"%s\" to an integer: %v", fields[1], err)
+			}
+			return pid, nil
+		}
+	}
+	return -1, nil
+}
+
+// ReadLinesFromPipe reads from the given pipe and logs its output.
+func ReadLinesFromPipe(pipe io.Reader, lines chan string) {
+	buf := []byte{}
+
+	// writeLine recovers from a panic when writing to the channel.
+	writeLine := func(s string) {
+		defer func() {
+			if r := recover(); r != nil {
+				glog.Warningf("Panic writing to channel... are we exiting?")
+			}
+		}()
+		lines <- s
+	}
+
+	// readLines reads output lines from the buffer and pushes them into the channel.
+	readlines := func() {
+		readIdx := 0
+		// Read lines from buf.
+		for i, b := range buf {
+			if b == '\n' {
+				s := string(buf[readIdx:i])
+				writeLine(s)
+				readIdx = i + 1
+			}
+		}
+		// Remove the lines we read.
+		buf = buf[readIdx:]
+	}
+
+	// Loop forever, reading bytes from the pipe.
+	readbuf := make([]byte, 4096)
+	for {
+		read, err := pipe.Read(readbuf)
+		if read > 0 {
+			buf = append(buf, readbuf[:read]...)
+
+			// Read lines from the buffers.
+			readlines()
+		}
+		if err != nil {
+			if err == io.EOF {
+				break
+			} else {
+				glog.Error(err)
+			}
+		} else if read == 0 {
+			time.Sleep(20 * time.Millisecond)
+		}
+	}
+	// Read any remaining lines from the buffers.
+	readlines()
+	// "Flush" any incomplete lines from the buffers.
+	writeLine(string(buf))
+}
+
+// RunApp launches the given app on the device, pipes its log output to stdout,
+// and returns when the app finishes running, with an error if the app did not
+// complete successfully.
+func RunApp(adb *ADB, appName string, args []string) error {
+	// Kill any running instances of the app.
+	if err := adb.Kill(COM_SKIA); err != nil {
+		return fmt.Errorf("Failed to kill app: %v", err)
+	}
+
+	// Clear the ADB log.
+	if err := adb.Cmd(false, "logcat", "-c").Run(); err != nil {
+		return fmt.Errorf("Failed to clear ADB log: %v", err)
+	}
+
+	// Prepare to read the subprocess output.
+	logProc := adb.Cmd(false, "logcat")
+	defer func() {
+		// Cleanup.
+		if err := logProc.Process.Kill(); err != nil {
+			glog.Errorf("Failed to kill logcat process: %v", err)
+		}
+	}()
+
+	stdout, err := logProc.StdoutPipe()
+	if err != nil {
+		return fmt.Errorf("Failed to obtain stdout pipe: %v", err)
+	}
+	stdoutLines := make(chan string)
+	stderr, err := logProc.StderrPipe()
+	if err != nil {
+		return fmt.Errorf("Failed to obtain stderr pipe: %v", err)
+	}
+	stderrLines := make(chan string)
+
+	go ReadLinesFromPipe(stdout, stdoutLines)
+	go ReadLinesFromPipe(stderr, stderrLines)
+	if err := logProc.Start(); err != nil {
+		return fmt.Errorf("Failed to start logcat process.")
+	}
+
+	// Launch the app.
+	stop := make(chan bool, 1)
+	activity := fmt.Sprintf("%s.%s/%s.%sActivity", COM_SKIA, strings.ToLower(appName), COM_SKIA, appName)
+	flags := strings.Join(args, " ")
+	cmd := []string{"shell", "am", "start", "-S", "-n", activity, "--es", "cmdLineFlags", flags}
+	output, err := adb.Cmd(true, cmd...).Output()
+	if err != nil {
+		return fmt.Errorf("Failed to launch app: %v", err)
+	}
+	glog.Info(string(output))
+	// Make a handler for SIGINT so that we can kill the app if this script is interrupted.
+	go func() {
+		interrupt := make(chan os.Signal, 1)
+		signal.Notify(interrupt, os.Interrupt)
+		for _ = range interrupt {
+			glog.Infof("Received SIGINT; killing app.")
+			stop <- true
+			close(stdoutLines)
+			close(stderrLines)
+			if err := adb.Kill(COM_SKIA); err != nil {
+				glog.Errorf("Failed to kill app: %v", err)
+			}
+			if err := logProc.Process.Kill(); err != nil {
+				glog.Errorf("Failed to kill logcat process: %v", err)
+			}
+		}
+	}()
+
+	// Loop until the app finishes or we're interrupted, writing output as appropriate.
+	// TODO(borenet): VisualBench should print its exit code. This script should exit
+	// with that code, or a non-zero code if the process ended without printing any code.
+	second := time.Tick(time.Second)
+PollLoop:
+	for {
+		select {
+		case <-second:
+			// Poll the Skia process every second to make sure it's still running.
+			pid, err := adb.Poll(COM_SKIA)
+			if err != nil {
+				glog.Errorf("Failed to poll Skia process: %v", err)
+			} else if pid < 0 {
+				glog.Infof("Skia process is no longer running!")
+				break PollLoop
+			}
+		case <-stop:
+			break PollLoop
+		case line := <-stdoutLines:
+			glog.Info(line)
+		case line := <-stderrLines:
+			glog.Error(line)
+		}
+	}
+
+	return nil
+}
+
+func main() {
+	common.Init()
+	args := flag.Args()
+	if err := RunApp(ADBFromFlags(), *app, args); err != nil {
+		glog.Fatal(err)
+	}
+}