Add a retry mechanism for the ADB command "root”. (#690)
Error "adb: unable to connect for root: closed" often occurs if `adb root` is called right after `adb reboot`. Add a retry for `adb root` to avoid this.
diff --git a/mobly/controllers/android_device_lib/adb.py b/mobly/controllers/android_device_lib/adb.py
index 05c2af0..fbcfd7d 100644
--- a/mobly/controllers/android_device_lib/adb.py
+++ b/mobly/controllers/android_device_lib/adb.py
@@ -28,6 +28,11 @@
# do with port forwarding must happen under this lock.
ADB_PORT_LOCK = threading.Lock()
+# Number of attempts to execute "adb root", and seconds for interval time of
+# this commands.
+ADB_ROOT_RETRY_ATTMEPTS = 3
+ADB_ROOT_RETRY_ATTEMPT_INTERVAL_SEC = 10
+
# Qualified class name of the default instrumentation test runner.
DEFAULT_INSTRUMENTATION_RUNNER = 'com.android.common.support.test.runner.AndroidJUnitRunner'
@@ -456,6 +461,38 @@
return self._execute_adb_and_process_stdout(
'shell', instrumentation_command, shell=False, handler=handler)
+ def root(self):
+ """Enables ADB root mode on the device.
+
+ This method will retry to execute the command `adb root` when an
+ AdbError occurs, since sometimes the error `adb: unable to connect
+ for root: closed` is raised when executing `adb root` immediately after
+ the device is booted to OS.
+
+ Returns:
+ A string that is the stdout of root command.
+
+ Raises:
+ AdbError: If the command exit code is not 0.
+ """
+ for attempt in range(ADB_ROOT_RETRY_ATTMEPTS):
+ try:
+ return self._exec_adb_cmd('root',
+ args=None,
+ shell=False,
+ timeout=None,
+ stderr=None)
+ except AdbError as e:
+ if attempt + 1 < ADB_ROOT_RETRY_ATTMEPTS:
+ logging.debug(
+ 'Retry the command "%s" since Error "%s" occurred.' %
+ (utils.cli_cmd_to_string(e.cmd),
+ e.stderr.decode('utf-8').strip()))
+ # Buffer between "adb root" commands.
+ time.sleep(ADB_ROOT_RETRY_ATTEMPT_INTERVAL_SEC)
+ else:
+ raise e
+
def __getattr__(self, name):
def adb_call(args=None, shell=False, timeout=None, stderr=None):
"""Wrapper for an ADB command.
diff --git a/tests/mobly/controllers/android_device_lib/adb_test.py b/tests/mobly/controllers/android_device_lib/adb_test.py
index e4180cf..e920bbd 100755
--- a/tests/mobly/controllers/android_device_lib/adb_test.py
+++ b/tests/mobly/controllers/android_device_lib/adb_test.py
@@ -40,6 +40,12 @@
'.instrumentation.tests/com.android'
'.common.support.test.runner'
'.AndroidJUnitRunner')
+
+# Mock root command outputs.
+MOCK_ROOT_SUCCESS_OUTPUT = 'adbd is already running as root'
+MOCK_ROOT_ERROR_OUTPUT = (
+ 'adb: unable to connect for root: closed'.encode('utf-8'))
+
# Mock Shell Command
MOCK_SHELL_COMMAND = 'ls'
MOCK_COMMAND_OUTPUT = '/system/bin/ls'.encode('utf-8')
@@ -712,6 +718,54 @@
self.assertEqual(stderr,
mock_execute_and_process_stdout.return_value)
+ @mock.patch.object(adb.AdbProxy, '_exec_cmd')
+ def test_root_success(self, mock_exec_cmd):
+ mock_exec_cmd.return_value = MOCK_ROOT_SUCCESS_OUTPUT
+ output = adb.AdbProxy().root()
+ mock_exec_cmd.assert_called_once_with(
+ ['adb', 'root'],
+ shell=False,
+ timeout=None,
+ stderr=None)
+ self.assertEqual(output, MOCK_ROOT_SUCCESS_OUTPUT)
+
+ @mock.patch('time.sleep', return_value=mock.MagicMock())
+ @mock.patch.object(adb.AdbProxy, '_exec_cmd')
+ def test_root_success_with_retry(self, mock_exec_cmd, mock_sleep):
+ mock_exec_cmd.side_effect = [
+ adb.AdbError('adb root', '', MOCK_ROOT_ERROR_OUTPUT, 1),
+ MOCK_ROOT_SUCCESS_OUTPUT]
+ output = adb.AdbProxy().root()
+ mock_exec_cmd.assert_called_with(
+ ['adb', 'root'],
+ shell=False,
+ timeout=None,
+ stderr=None)
+ self.assertEqual(output, MOCK_ROOT_SUCCESS_OUTPUT)
+ self.assertEqual(mock_sleep.call_count, 1)
+ mock_sleep.assert_called_with(10)
+
+ @mock.patch('time.sleep', return_value=mock.MagicMock())
+ @mock.patch.object(adb.AdbProxy, '_exec_cmd')
+ def test_root_raises_adb_error_when_all_retries_failed(self, mock_exec_cmd,
+ mock_sleep):
+ mock_exec_cmd.side_effect = adb.AdbError('adb root',
+ '',
+ MOCK_ROOT_ERROR_OUTPUT,
+ 1)
+ expected_msg = ('Error executing adb cmd "adb root". '
+ 'ret: 1, stdout: , stderr: %s' %
+ MOCK_ROOT_ERROR_OUTPUT)
+ with self.assertRaisesRegex(adb.AdbError, expected_msg):
+ adb.AdbProxy().root()
+ mock_exec_cmd.assert_called_with(
+ ['adb', 'root'],
+ shell=False,
+ timeout=None,
+ stderr=None)
+ self.assertEqual(mock_sleep.call_count, 2)
+ mock_sleep.assert_called_with(10)
+
def test_has_shell_command_called_correctly(self):
with mock.patch.object(adb.AdbProxy, '_exec_cmd') as mock_exec_cmd:
mock_exec_cmd.return_value = MOCK_DEFAULT_COMMAND_OUTPUT
