1# Copyright (c) 2011 The Chromium OS Authors. 2# 3# SPDX-License-Identifier: GPL-2.0+ 4# 5 6import os 7import cros_subprocess 8 9"""Shell command ease-ups for Python.""" 10 11class 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.return_code = None 24 self.exception = None 25 26 27def RunPipe(pipe_list, infile=None, outfile=None, 28 capture=False, capture_stderr=False, oneline=False, 29 raise_on_error=True, cwd=None, **kwargs): 30 """ 31 Perform a command pipeline, with optional input/output filenames. 32 33 Args: 34 pipe_list: List of command lines to execute. Each command line is 35 piped into the next, and is itself a list of strings. For 36 example [ ['ls', '.git'] ['wc'] ] will pipe the output of 37 'ls .git' into 'wc'. 38 infile: File to provide stdin to the pipeline 39 outfile: File to store stdout 40 capture: True to capture output 41 capture_stderr: True to capture stderr 42 oneline: True to strip newline chars from output 43 kwargs: Additional keyword arguments to cros_subprocess.Popen() 44 Returns: 45 CommandResult object 46 """ 47 result = CommandResult() 48 last_pipe = None 49 pipeline = list(pipe_list) 50 user_pipestr = '|'.join([' '.join(pipe) for pipe in pipe_list]) 51 while pipeline: 52 cmd = pipeline.pop(0) 53 if last_pipe is not None: 54 kwargs['stdin'] = last_pipe.stdout 55 elif infile: 56 kwargs['stdin'] = open(infile, 'rb') 57 if pipeline or capture: 58 kwargs['stdout'] = cros_subprocess.PIPE 59 elif outfile: 60 kwargs['stdout'] = open(outfile, 'wb') 61 if capture_stderr: 62 kwargs['stderr'] = cros_subprocess.PIPE 63 64 try: 65 last_pipe = cros_subprocess.Popen(cmd, cwd=cwd, **kwargs) 66 except Exception, err: 67 result.exception = err 68 if raise_on_error: 69 raise Exception("Error running '%s': %s" % (user_pipestr, str)) 70 result.return_code = 255 71 return result 72 73 if capture: 74 result.stdout, result.stderr, result.combined = ( 75 last_pipe.CommunicateFilter(None)) 76 if result.stdout and oneline: 77 result.output = result.stdout.rstrip('\r\n') 78 result.return_code = last_pipe.wait() 79 else: 80 result.return_code = os.waitpid(last_pipe.pid, 0)[1] 81 if raise_on_error and result.return_code: 82 raise Exception("Error running '%s'" % user_pipestr) 83 return result 84 85def Output(*cmd): 86 return RunPipe([cmd], capture=True, raise_on_error=False).stdout 87 88def OutputOneLine(*cmd, **kwargs): 89 raise_on_error = kwargs.pop('raise_on_error', True) 90 return (RunPipe([cmd], capture=True, oneline=True, 91 raise_on_error=raise_on_error, 92 **kwargs).stdout.strip()) 93 94def Run(*cmd, **kwargs): 95 return RunPipe([cmd], **kwargs).stdout 96 97def RunList(cmd): 98 return RunPipe([cmd], capture=True).stdout 99 100def StopAll(): 101 cros_subprocess.stay_alive = False 102