Target.execute(): Add .returncode and .output exception attributes

Add Target{Stable,Transient}CalledProcessError exceptions, with an
.returncode and .output attributes, raised by Target.execute(),
mirroring subprocess.CalledProcessError.

This is very useful in client code that uses "exit N" to signal an
abnormal condition, and then inspects the output to find out more.

devlib/exception.py

@@ -13,6 +13,8 @@
 # limitations under the License.
 #
 
+import subprocess
+
 class DevlibError(Exception):
     """Base class for all Devlib exceptions."""
 
@@ -69,6 +71,42 @@ class TargetStableError(TargetError, DevlibStableError):
     pass
 
 
+class TargetCalledProcessError(subprocess.CalledProcessError, TargetError):
+    """Exception raised when a command executed on the target fails."""
+    def __str__(self):
+        msg = super().__str__()
+        def decode(s):
+            try:
+                s = s.decode()
+            except AttributeError:
+                s = str(s)
+
+            return s.strip()
+
+        if self.stdout is not None and self.stderr is None:
+            out = ['OUTPUT: {}'.format(decode(self.output))]
+        else:
+            out = [
+                'STDOUT: {}'.format(decode(self.output)) if self.output is not None else '',
+                'STDERR: {}'.format(decode(self.stderr)) if self.stderr is not None else '',
+            ]
+
+        return '\n'.join((
+            msg,
+            *out,
+        ))
+
+
+class TargetStableCalledProcessError(TargetCalledProcessError, TargetStableError):
+    """Variant of :exc:`devlib.exception.TargetCalledProcessError` that indicates a stable error"""
+    pass
+
+
+class TargetTransientCalledProcessError(TargetCalledProcessError, TargetTransientError):
+    """Variant of :exc:`devlib.exception.TargetCalledProcessError` that indicates a transient error"""
+    pass
+
+
 class TargetNotRespondingError(TargetTransientError):
     """The target is unresponsive."""
     pass

devlib/host.py

@@ -22,7 +22,10 @@ from distutils.dir_util import copy_tree
 from getpass import getpass
 from pipes import quote
 
-from devlib.exception import TargetTransientError, TargetStableError
+from devlib.exception import (
+    TargetTransientError, TargetStableError,
+    TargetTransientCalledProcessError, TargetStableCalledProcessError
+)
 from devlib.utils.misc import check_output
 from devlib.connection import ConnectionBase, PopenBackgroundCommand
 
@@ -102,12 +105,13 @@ class LocalConnection(ConnectionBase):
         try:
             stdout, stderr = check_output(command, shell=True, timeout=timeout, ignore=ignore)
         except subprocess.CalledProcessError as e:
-            message = 'Got exit code {}\nfrom: {}\nOUTPUT: {}'.format(
-                e.returncode, command, e.output)
-            if will_succeed:
-                raise TargetTransientError(message)
-            else:
-                raise TargetStableError(message)
+            cls = TargetTransientCalledProcessError if will_succeed else TargetStableCalledProcessError
+            raise cls(
+                e.returncode,
+                command,
+                e.output,
+                e.stderr,
+            )
 
         # Remove the one-character prompt of sudo -S -p
         if use_sudo and stderr:

devlib/utils/android.py

@@ -40,7 +40,7 @@ try:
 except ImportError:
     from pipes import quote
 
-from devlib.exception import TargetTransientError, TargetStableError, HostError
+from devlib.exception import TargetTransientError, TargetStableError, HostError, TargetTransientCalledProcessError, TargetStableCalledProcessError
 from devlib.utils.misc import check_output, which, ABI_MAP, redirect_streams, get_subprocess
 from devlib.connection import ConnectionBase, AdbBackgroundCommand, PopenBackgroundCommand, PopenTransferManager
 
@@ -336,6 +336,14 @@ class AdbConnection(ConnectionBase):
         try:
             return adb_shell(self.device, command, timeout, check_exit_code,
                              as_root, adb_server=self.adb_server, su_cmd=self.su_cmd)
+        except subprocess.CalledProcessError as e:
+            cls = TargetTransientCalledProcessError if will_succeed else TargetStableCalledProcessError
+            raise cls(
+                e.returncode,
+                command,
+                e.output,
+                e.stderr,
+            )
         except TargetStableError as e:
             if will_succeed:
                 raise TargetTransientError(e)
@@ -559,10 +567,15 @@ def adb_shell(device, command, timeout=None, check_exit_code=False,
         exit_code = exit_code.strip()
         re_search = AM_START_ERROR.findall(output)
         if exit_code.isdigit():
-            if int(exit_code):
-                message = ('Got exit code {}\nfrom target command: {}\n'
-                           'OUTPUT: {}\nSTDERR: {}\n')
-                raise TargetStableError(message.format(exit_code, command, output, error))
+            exit_code = int(exit_code)
+            if exit_code:
+                raise subprocess.CalledProcessError(
+                    exit_code,
+                    command,
+                    output,
+                    error,
+                )
+
             elif re_search:
                 message = 'Could not start activity; got the following:\n{}'
                 raise TargetStableError(message.format(re_search[0]))

devlib/utils/misc.py

@@ -197,7 +197,7 @@ def check_subprocess_output(process, timeout=None, ignore=None, inputtext=None):
 
     retcode = process.poll()
     if retcode and ignore != 'all' and retcode not in ignore:
-        raise subprocess.CalledProcessError(retcode, process.args, output='\n'.join([output, error]))
+        raise subprocess.CalledProcessError(retcode, process.args, output, error)
 
     return output, error
 

devlib/utils/ssh.py

@@ -52,7 +52,10 @@ from pexpect import EOF, TIMEOUT, spawn
 
 # pylint: disable=redefined-builtin,wrong-import-position
 from devlib.exception import (HostError, TargetStableError, TargetNotRespondingError,
-                              TimeoutError, TargetTransientError)
+                              TimeoutError, TargetTransientError,
+                              TargetCalledProcessError,
+                              TargetTransientCalledProcessError,
+                              TargetStableCalledProcessError)
 from devlib.utils.misc import (which, strip_bash_colors, check_output,
                                sanitize_cmd_template, memoized, redirect_streams)
 from devlib.utils.types import boolean
@@ -524,6 +527,8 @@ class SshConnection(SshConnectionBase):
         try:
             with _handle_paramiko_exceptions(command):
                 exit_code, output = self._execute(command, timeout, as_root, strip_colors)
+        except TargetCalledProcessError:
+            raise
         except TargetStableError as e:
             if will_succeed:
                 raise TargetTransientError(e)
@@ -531,8 +536,13 @@ class SshConnection(SshConnectionBase):
                 raise
         else:
             if check_exit_code and exit_code:
-                message = 'Got exit code {}\nfrom: {}\nOUTPUT: {}'
-                raise TargetStableError(message.format(exit_code, command, output))
+                cls = TargetTransientCalledProcessError if will_succeed else TargetStableCalledProcessError
+                raise cls(
+                    exit_code,
+                    command,
+                    output,
+                    None,
+                )
             return output
 
     def background(self, command, stdout=subprocess.PIPE, stderr=subprocess.PIPE, as_root=False):
@@ -843,16 +853,23 @@ class TelnetConnection(SshConnectionBase):
                 if check_exit_code:
                     try:
                         exit_code = int(exit_code_text)
-                        if exit_code:
-                            message = 'Got exit code {}\nfrom: {}\nOUTPUT: {}'
-                            raise TargetStableError(message.format(exit_code, command, output))
                     except (ValueError, IndexError):
-                        logger.warning(
+                        raise ValueError(
                             'Could not get exit code for "{}",\ngot: "{}"'\
                             .format(command, exit_code_text))
+                    if exit_code:
+                        cls = TargetTransientCalledProcessError if will_succeed else TargetStableCalledProcessError
+                        raise cls(
+                            exit_code,
+                            command,
+                            output,
+                            None,
+                        )
                 return output
         except EOF:
             raise TargetNotRespondingError('Connection lost.')
+        except TargetCalledProcessError:
+            raise
         except TargetStableError as e:
             if will_succeed:
                 raise TargetTransientError(e)
@@ -1130,7 +1147,10 @@ class Gem5Connection(TelnetConnection):
         try:
             output = self._gem5_shell(command,
                                       check_exit_code=check_exit_code,
-                                      as_root=as_root)
+                                      as_root=as_root,
+                                      will_succeed=will_succeed)
+        except TargetCalledProcessError:
+            raise
         except TargetStableError as e:
             if will_succeed:
                 raise TargetTransientError(e)
@@ -1364,7 +1384,7 @@ class Gem5Connection(TelnetConnection):
             raise TargetStableError('Path to m5 binary on simulated system  is not set!')
         self._gem5_shell('{} {}'.format(self.m5_path, command))
 
-    def _gem5_shell(self, command, as_root=False, timeout=None, check_exit_code=True, sync=True):  # pylint: disable=R0912
+    def _gem5_shell(self, command, as_root=False, timeout=None, check_exit_code=True, sync=True, will_succeed=False):  # pylint: disable=R0912
         """
         Execute a command in the gem5 shell
 
@@ -1429,11 +1449,17 @@ class Gem5Connection(TelnetConnection):
                                              sync=False)
             try:
                 exit_code = int(exit_code_text.split()[0])
-                if exit_code:
-                    message = 'Got exit code {}\nfrom: {}\nOUTPUT: {}'
-                    raise TargetStableError(message.format(exit_code, command, output))
             except (ValueError, IndexError):
-                gem5_logger.warning('Could not get exit code for "{}",\ngot: "{}"'.format(command, exit_code_text))
+                raise ValueError('Could not get exit code for "{}",\ngot: "{}"'.format(command, exit_code_text))
+            else:
+                if exit_code:
+                    cls = TragetTransientCalledProcessError if will_succeed else TargetStableCalledProcessError
+                    raise cls(
+                        exit_code,
+                        command,
+                        output,
+                        None,
+                    )
 
         return output