tools/patman/command.py

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