Support HTTP test-server based net unit tests on Android.

build/android/pylib/forwarder.py

Index: build/android/pylib/forwarder.py
diff --git a/build/android/pylib/forwarder.py b/build/android/pylib/forwarder.py
index bc41db3ff3be7d9e6e64d48a795f5f438e3482e8..a0dc5f2fcc1d7ff59696d988968eeb85d614570b 100644
--- a/build/android/pylib/forwarder.py
+++ b/build/android/pylib/forwarder.py
@@ -15,6 +15,11 @@ import ports
 
 from pylib import pexpect
 
+
+def _MakeBinaryPath(build_type, binary_name):
+  return os.path.join(constants.CHROME_DIR, 'out', build_type, binary_name)
+
+
 class Forwarder(object):
   """Class to manage port forwards from the device to the host."""
 
@@ -24,13 +29,27 @@ class Forwarder(object):
   _DEVICE_ADB_CONTROL_PORT = 'chrome_device_forwarder'
   _TIMEOUT_SECS = 30
 
-  def __init__(self, adb, port_pairs, tool, host_name, build_type):
+  def __init__(self, adb, build_type):
     """Forwards TCP ports on the device back to the host.
 
     Works like adb forward, but in reverse.
 
     Args:
       adb: Instance of AndroidCommands for talking to the device.
+      build_type: 'Release' or 'Debug'.
+    """
+    assert build_type in ('Release', 'Debug')
+    self._adb = adb
+    self._host_to_device_port_map = dict()
+    self._device_process = None
+    self._host_forwarder_path = _MakeBinaryPath(build_type, 'host_forwarder')
+    self._device_forwarder_path = _MakeBinaryPath(
+        build_type, 'device_forwarder')
+
+  def Run(self, port_pairs, tool, host_name):
+    """Runs the forwarder.
+
+    Args:
       port_pairs: A list of tuples (device_port, host_port) to forward. Note
                  that you can specify 0 as a device_port, in which case a
                  port will by dynamically assigned on the device. You can
@@ -40,159 +59,104 @@ class Forwarder(object):
             forwarder (see valgrind_tools.py).
       host_name: Address to forward to, must be addressable from the
                  host machine. Usually use loopback '127.0.0.1'.
-      build_type: 'Release' or 'Debug'.
 
     Raises:
       Exception on failure to forward the port.
     """
-    self._adb = adb
-    self._host_to_device_port_map = dict()
-    self._host_process = None
-    self._device_process = None
-    self._adb_forward_process = None
-
-    self._host_adb_control_port = ports.AllocateTestServerPort()
-    if not self._host_adb_control_port:
+    host_adb_control_port = ports.AllocateTestServerPort()
+    if not host_adb_control_port:
       raise Exception('Failed to allocate a TCP port in the host machine.')
-    adb.PushIfNeeded(
-        os.path.join(constants.CHROME_DIR, 'out', build_type,
-                     'device_forwarder'),
-        Forwarder._DEVICE_FORWARDER_PATH)
-    self._host_forwarder_path = os.path.join(constants.CHROME_DIR,
-                                             'out',
-                                             build_type,
-                                             'host_forwarder')
-    forward_string = ['%d:%d:%s' %
-                      (device, host, host_name) for device, host in port_pairs]
-    logging.info('Forwarding ports: %s', forward_string)
-    timeout_sec = 5
-    host_pattern = 'host_forwarder.*' + ' '.join(forward_string)
-    # TODO(felipeg): Rather than using a blocking kill() here, the device
-    # forwarder could try to bind the Unix Domain Socket until it succeeds or
-    # while it fails because the socket is already bound (with appropriate
-    # timeout handling obviously).
-    self._KillHostForwarderBlocking(host_pattern, timeout_sec)
-    self._KillDeviceForwarderBlocking(timeout_sec)
-    self._adb_forward_process = pexpect.spawn(
-        'adb', ['-s',
-                adb._adb.GetSerialNumber(),
-                'forward',
-                'tcp:%s' % self._host_adb_control_port,
-                'localabstract:%s' % Forwarder._DEVICE_ADB_CONTROL_PORT])
-    self._device_process = pexpect.spawn(
-        'adb', ['-s',
-                adb._adb.GetSerialNumber(),
-                'shell',
-                '%s %s -D --adb_sock=%s' % (
-                    tool.GetUtilWrapper(),
-                    Forwarder._DEVICE_FORWARDER_PATH,
-                    Forwarder._DEVICE_ADB_CONTROL_PORT)])
-
-    device_success_re = re.compile('Starting Device Forwarder.')
-    device_failure_re = re.compile('.*:ERROR:(.*)')
-    index = self._device_process.expect([device_success_re,
-                                         device_failure_re,
-                                         pexpect.EOF,
-                                         pexpect.TIMEOUT],
-                                        Forwarder._TIMEOUT_SECS)
-    if index == 1:
-      # Failure
-      error_msg = str(self._device_process.match.group(1))
-      logging.error(self._device_process.before)
-      self._CloseProcess()
-      raise Exception('Failed to start Device Forwarder with Error: %s' %
-                      error_msg)
-    elif index == 2:
-      logging.error(self._device_process.before)
-      self._CloseProcess()
-      raise Exception('Unexpected EOF while trying to start Device Forwarder.')
-    elif index == 3:
-      logging.error(self._device_process.before)
-      self._CloseProcess()
-      raise Exception('Timeout while trying start Device Forwarder')
-
-    self._host_process = pexpect.spawn(self._host_forwarder_path,
-                                       ['--adb_port=%s' % (
-                                           self._host_adb_control_port)] +
-                                       forward_string)
-
-    # Read the output of the command to determine which device ports where
-    # forwarded to which host ports (necessary if
-    host_success_re = re.compile('Forwarding device port (\d+) to host (\d+):')
-    host_failure_re = re.compile('Couldn\'t start forwarder server for port '
-                                 'spec: (\d+):(\d+)')
-    for pair in port_pairs:
-      index = self._host_process.expect([host_success_re,
-                                         host_failure_re,
-                                         pexpect.EOF,
-                                         pexpect.TIMEOUT],
-                                        Forwarder._TIMEOUT_SECS)
-      if index == 0:
-        # Success
-        device_port = int(self._host_process.match.group(1))
-        host_port = int(self._host_process.match.group(2))
-        self._host_to_device_port_map[host_port] = device_port
-        logging.info("Forwarding device port: %d to host port: %d." %
-                     (device_port, host_port))
-      elif index == 1:
-        # Failure
-        device_port = int(self._host_process.match.group(1))
-        host_port = int(self._host_process.match.group(2))
-        self._CloseProcess()
-        raise Exception('Failed to forward port %d to %d' % (device_port,
-                                                             host_port))
+    self._adb.PushIfNeeded(self._device_forwarder_path,
+                           Forwarder._DEVICE_FORWARDER_PATH)
+    redirection_commands = [
+        '%d:%d:%d:%s' % (host_adb_control_port, device, host,
+                         host_name) for device, host in port_pairs]
+    logging.info('Command format: <ADB port>:<Device port>' +
+                 '[:<Forward to port>:<Forward to address>]')
+    logging.info('Forwarding using commands: %s', redirection_commands)
+    if cmd_helper.RunCmd(
+        ['adb', '-s', self._adb._adb.GetSerialNumber(), 'forward',
+         'tcp:%s' % host_adb_control_port,
+         'localabstract:%s' % Forwarder._DEVICE_ADB_CONTROL_PORT]) != 0:
+      raise Exception('Error while running adb forward.')
+
+    if not self._adb.ExtractPid('device_forwarder'):
+      # TODO(pliard): Get rid of pexpect here and make device_forwarder a daemon
+      # with a blocking CLI process that exits with a proper exit code and not
+      # while the daemon is still setting up. This would be similar to how
+      # host_forwarder works.
+      self._device_process = pexpect.spawn(
+          'adb', ['-s',
+                  self._adb._adb.GetSerialNumber(),
+                  'shell',
+                  '%s %s -D --adb_sock=%s' % (
+                      tool.GetUtilWrapper(),
+                      Forwarder._DEVICE_FORWARDER_PATH,
+                      Forwarder._DEVICE_ADB_CONTROL_PORT)])
+      device_success_re = re.compile('Starting Device Forwarder.')
+      device_failure_re = re.compile('.*:ERROR:(.*)')
+      index = self._device_process.expect([device_success_re,
+                                           device_failure_re,
+                                           pexpect.EOF,
+                                           pexpect.TIMEOUT],
+                                           Forwarder._TIMEOUT_SECS)
+      if index == 1:
+        error_msg = str(self._device_process.match.group(1))
+        logging.error(self._device_process.before)
+        self._device_process.close()
+        raise Exception('Failed to start Device Forwarder with Error: %s' %
+                        error_msg)
       elif index == 2:
-        logging.error(self._host_process.before)
-        self._CloseProcess()
-        raise Exception('Unexpected EOF while trying to forward ports %s' %
-                        port_pairs)
+        logging.error(self._device_process.before)
+        self._device_process.close()
+        raise Exception(
+            'Unexpected EOF while trying to start Device Forwarder.')
       elif index == 3:
-        logging.error(self._host_process.before)
-        self._CloseProcess()
-        raise Exception('Timeout while trying to forward ports %s' % port_pairs)
-
-  def _KillHostForwarderBlocking(self, host_pattern, timeout_sec):
-    """Kills any existing host forwarders using the provided pattern.
-
-    Note that this waits until the process terminates.
-    """
-    cmd_helper.RunCmd(['pkill', '-f', host_pattern])
-    elapsed = 0
-    wait_period = 0.1
-    while not cmd_helper.RunCmd(['pgrep', '-f', host_pattern]) and (
-        elapsed < timeout_sec):
-      time.sleep(wait_period)
-      elapsed += wait_period
-    if elapsed >= timeout_sec:
-        raise Exception('Timed out while killing ' + host_pattern)
-
-  def _KillDeviceForwarderBlocking(self, timeout_sec):
-    """Kills any existing device forwarders.
-
-    Note that this waits until the process terminates.
-    """
-    processes_killed = self._adb.KillAllBlocking(
-        'device_forwarder', timeout_sec)
+        logging.error(self._device_process.before)
+        self._device_process.close()
+        raise Exception('Timeout while trying start Device Forwarder')
+
+    for redirection_command in redirection_commands:
+      (exit_code, output) = cmd_helper.GetCmdStatusAndOutput(
+          [self._host_forwarder_path, redirection_command])
+      if exit_code != 0:
+        raise Exception('%s exited with %d: %s' % (self._host_forwarder_path,
+                                                   exit_code, output))
+      tokens = output.split(':')
+      if len(tokens) != 2:
+        raise Exception('Unexpected host forwarder output "%s", ' +
+                        'expected "device_port:host_port"' % output)
+      device_port = int(tokens[0])
+      host_port = int(tokens[1])
+      self._host_to_device_port_map[host_port] = device_port
+      logging.info('Forwarding device port: %d to host port: %d.', device_port,
+                   host_port)
+
+  @staticmethod
+  def KillHost(build_type):
+    host_forwarder_path = _MakeBinaryPath(build_type, 'host_forwarder')
+    (exit_code, output) = cmd_helper.GetCmdStatusAndOutput(
+        [host_forwarder_path, 'kill-server'])
+    if exit_code != 0:
+      raise Exception('%s exited with %d: %s' % (host_forwarder_path,
+                                                 exit_code, output))
+
+  @staticmethod
+  def KillDevice(adb):
+    logging.info('Killing device_forwarder.')
+    timeout_sec = 5
+    processes_killed = adb.KillAllBlocking('device_forwarder', timeout_sec)
     if not processes_killed:
-      pids = self._adb.ExtractPid('device_forwarder')
+      pids = adb.ExtractPid('device_forwarder')
       if pids:
         raise Exception('Timed out while killing device_forwarder')
 
-  def _CloseProcess(self):
-    if self._host_process:
-      self._host_process.close()
-    if self._device_process:
-      self._device_process.close()
-    if self._adb_forward_process:
-      self._adb_forward_process.close()
-    self._host_process = None
-    self._device_process = None
-    self._adb_forward_process = None
-
   def DevicePortForHostPort(self, host_port):
     """Get the device port that corresponds to a given host port."""
     return self._host_to_device_port_map.get(host_port)
 
   def Close(self):
     """Terminate the forwarder process."""
-    self._CloseProcess()
+    if self._device_process:
+      self._device_process.close()
+      self._device_process = None