tools/patman/command.py

   1 # SPDX-License-Identifier: GPL-2.0+
   2 # Copyright (c) 2011 The Chromium OS Authors.
   3 #
   4
   5 import os
   6 import cros_subprocess
   7
   8 """Shell command ease-ups for Python."""
   9
  10 class CommandResult:
  11     """A class which captures the result of executing a command.
  12
  13     Members:
  14         stdout: stdout obtained from command, as a string
  15         stderr: stderr obtained from command, as a string
  16         return_code: Return code from command
  17         exception: Exception received, or None if all ok
  18     """
  19     def __init__(self):
  20         self.stdout = None
  21         self.stderr = None
  22         self.combined = None
  23         self.return_code = None
  24         self.exception = None
  25
  26     def __init__(self, stdout='', stderr='', combined='', return_code=0,
  27                  exception=None):
  28         self.stdout = stdout
  29         self.stderr = stderr
  30         self.combined = combined
  31         self.return_code = return_code
  32         self.exception = exception
  33
  34
  35 # This permits interception of RunPipe for test purposes. If it is set to
  36 # a function, then that function is called with the pipe list being
  37 # executed. Otherwise, it is assumed to be a CommandResult object, and is
  38 # returned as the result for every RunPipe() call.
  39 # When this value is None, commands are executed as normal.
  40 test_result = None
  41
  42 def RunPipe(pipe_list, infile=None, outfile=None,
  43             capture=False, capture_stderr=False, oneline=False,
  44             raise_on_error=True, cwd=None, **kwargs):
  45     """
  46     Perform a command pipeline, with optional input/output filenames.
  47
  48     Args:
  49         pipe_list: List of command lines to execute. Each command line is
  50             piped into the next, and is itself a list of strings. For
  51             example [ ['ls', '.git'] ['wc'] ] will pipe the output of
  52             'ls .git' into 'wc'.
  53         infile: File to provide stdin to the pipeline
  54         outfile: File to store stdout
  55         capture: True to capture output
  56         capture_stderr: True to capture stderr
  57         oneline: True to strip newline chars from output
  58         kwargs: Additional keyword arguments to cros_subprocess.Popen()
  59     Returns:
  60         CommandResult object
  61     """
  62     if test_result:
  63         if hasattr(test_result, '__call__'):
  64             return test_result(pipe_list=pipe_list)
  65         return test_result
  66     result = CommandResult()
  67     last_pipe = None
  68     pipeline = list(pipe_list)
  69     user_pipestr =  '|'.join([' '.join(pipe) for pipe in pipe_list])
  70     kwargs['stdout'] = None
  71     kwargs['stderr'] = None
  72     while pipeline:
  73         cmd = pipeline.pop(0)
  74         if last_pipe is not None:
  75             kwargs['stdin'] = last_pipe.stdout
  76         elif infile:
  77             kwargs['stdin'] = open(infile, 'rb')
  78         if pipeline or capture:
  79             kwargs['stdout'] = cros_subprocess.PIPE
  80         elif outfile:
  81             kwargs['stdout'] = open(outfile, 'wb')
  82         if capture_stderr:
  83             kwargs['stderr'] = cros_subprocess.PIPE
  84
  85         try:
  86             last_pipe = cros_subprocess.Popen(cmd, cwd=cwd, **kwargs)
  87         except Exception as err:
  88             result.exception = err
  89             if raise_on_error:
  90                 raise Exception("Error running '%s': %s" % (user_pipestr, str))
  91             result.return_code = 255
  92             return result
  93
  94     if capture:
  95         result.stdout, result.stderr, result.combined = (
  96                 last_pipe.CommunicateFilter(None))
  97         if result.stdout and oneline:
  98             result.output = result.stdout.rstrip('\r\n')
  99         result.return_code = last_pipe.wait()
 100     else:
 101         result.return_code = os.waitpid(last_pipe.pid, 0)[1]
 102     if raise_on_error and result.return_code:
 103         raise Exception("Error running '%s'" % user_pipestr)
 104     return result
 105
 106 def Output(*cmd, **kwargs):
 107     raise_on_error = kwargs.get('raise_on_error', True)
 108     return RunPipe([cmd], capture=True, raise_on_error=raise_on_error).stdout
 109
 110 def OutputOneLine(*cmd, **kwargs):
 111     raise_on_error = kwargs.pop('raise_on_error', True)
 112     return (RunPipe([cmd], capture=True, oneline=True,
 113             raise_on_error=raise_on_error,
 114             **kwargs).stdout.strip())
 115
 116 def Run(*cmd, **kwargs):
 117     return RunPipe([cmd], **kwargs).stdout
 118
 119 def RunList(cmd):
 120     return RunPipe([cmd], capture=True).stdout
 121
 122 def StopAll():
 123     cros_subprocess.stay_alive = False