# This Source Code Form is subject to the terms of the Mozilla Public # License, v. 2.0. If a copy of the MPL was not distributed with this file, # You can obtain one at http://mozilla.org/MPL/2.0/. import os import select import signal import subprocess import sys import threading import time import traceback from Queue import Queue from datetime import datetime, timedelta __all__ = ['ProcessHandlerMixin', 'ProcessHandler'] # Set the MOZPROCESS_DEBUG environment variable to 1 to see some debugging output MOZPROCESS_DEBUG = os.getenv("MOZPROCESS_DEBUG") # We dont use mozinfo because it is expensive to import, see bug 933558. isWin = os.name == "nt" isPosix = os.name == "posix" # includes MacOS X if isWin: import ctypes, ctypes.wintypes, msvcrt from ctypes import sizeof, addressof, c_ulong, byref, POINTER, WinError, c_longlong import winprocess from qijo import JobObjectAssociateCompletionPortInformation,\ JOBOBJECT_ASSOCIATE_COMPLETION_PORT, JobObjectExtendedLimitInformation,\ JOBOBJECT_BASIC_LIMIT_INFORMATION, JOBOBJECT_EXTENDED_LIMIT_INFORMATION, IO_COUNTERS class ProcessHandlerMixin(object): """ A class for launching and manipulating local processes. :param cmd: command to run. May be a string or a list. If specified as a list, the first element will be interpreted as the command, and all additional elements will be interpreted as arguments to that command. :param args: list of arguments to pass to the command (defaults to None). Must not be set when `cmd` is specified as a list. :param cwd: working directory for command (defaults to None). :param env: is the environment to use for the process (defaults to os.environ). :param ignore_children: causes system to ignore child processes when True, defaults to False (which tracks child processes). :param kill_on_timeout: when True, the process will be killed when a timeout is reached. When False, the caller is responsible for killing the process. Failure to do so could cause a call to wait() to hang indefinitely. (Defaults to True.) :param processOutputLine: function to be called for each line of output produced by the process (defaults to None). :param onTimeout: function to be called when the process times out. :param onFinish: function to be called when the process terminates normally without timing out. :param kwargs: additional keyword args to pass directly into Popen. NOTE: Child processes will be tracked by default. If for any reason we are unable to track child processes and ignore_children is set to False, then we will fall back to only tracking the root process. The fallback will be logged. """ class Process(subprocess.Popen): """ Represents our view of a subprocess. It adds a kill() method which allows it to be stopped explicitly. """ MAX_IOCOMPLETION_PORT_NOTIFICATION_DELAY = 180 MAX_PROCESS_KILL_DELAY = 30 def __init__(self, args, bufsize=0, executable=None, stdin=None, stdout=None, stderr=None, preexec_fn=None, close_fds=False, shell=False, cwd=None, env=None, universal_newlines=False, startupinfo=None, creationflags=0, ignore_children=False): # Parameter for whether or not we should attempt to track child processes self._ignore_children = ignore_children if not self._ignore_children and not isWin: # Set the process group id for linux systems # Sets process group id to the pid of the parent process # NOTE: This prevents you from using preexec_fn and managing # child processes, TODO: Ideally, find a way around this def setpgidfn(): os.setpgid(0, 0) preexec_fn = setpgidfn try: subprocess.Popen.__init__(self, args, bufsize, executable, stdin, stdout, stderr, preexec_fn, close_fds, shell, cwd, env, universal_newlines, startupinfo, creationflags) except OSError, e: print >> sys.stderr, args raise def __del__(self, _maxint=sys.maxint): if isWin: if self._handle: if hasattr(self, '_internal_poll'): self._internal_poll(_deadstate=_maxint) else: self.poll(_deadstate=sys.maxint) if self._handle or self._job or self._io_port: self._cleanup() else: subprocess.Popen.__del__(self) def kill(self, sig=None): self.returncode = 0 if isWin: if not self._ignore_children and self._handle and self._job: winprocess.TerminateJobObject(self._job, winprocess.ERROR_CONTROL_C_EXIT) self.returncode = winprocess.GetExitCodeProcess(self._handle) elif self._handle: err = None try: winprocess.TerminateProcess(self._handle, winprocess.ERROR_CONTROL_C_EXIT) except: err = "Could not terminate process" self.returncode = winprocess.GetExitCodeProcess(self._handle) self._cleanup() if err is not None: raise OSError(err) else: sig = sig or signal.SIGKILL if not self._ignore_children: try: os.killpg(self.pid, sig) except BaseException, e: if getattr(e, "errno", None) != 3: # Error 3 is "no such process", which is ok print >> sys.stdout, "Could not kill process, could not find pid: %s, assuming it's already dead" % self.pid else: os.kill(self.pid, sig) self.returncode = -sig self._cleanup() return self.returncode def wait(self): """ Popen.wait Called to wait for a running process to shut down and return its exit code Returns the main process's exit code """ # This call will be different for each OS self.returncode = self._wait() self._cleanup() return self.returncode """ Private Members of Process class """ if isWin: # Redefine the execute child so that we can track process groups def _execute_child(self, *args_tuple): # workaround for bug 950894 if sys.hexversion < 0x02070600: # prior to 2.7.6 (args, executable, preexec_fn, close_fds, cwd, env, universal_newlines, startupinfo, creationflags, shell, p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite) = args_tuple to_close = set() else: # 2.7.6 and later (args, executable, preexec_fn, close_fds, cwd, env, universal_newlines, startupinfo, creationflags, shell, to_close, p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite) = args_tuple if not isinstance(args, basestring): args = subprocess.list2cmdline(args) # Always or in the create new process group creationflags |= winprocess.CREATE_NEW_PROCESS_GROUP if startupinfo is None: startupinfo = winprocess.STARTUPINFO() if None not in (p2cread, c2pwrite, errwrite): startupinfo.dwFlags |= winprocess.STARTF_USESTDHANDLES startupinfo.hStdInput = int(p2cread) startupinfo.hStdOutput = int(c2pwrite) startupinfo.hStdError = int(errwrite) if shell: startupinfo.dwFlags |= winprocess.STARTF_USESHOWWINDOW startupinfo.wShowWindow = winprocess.SW_HIDE comspec = os.environ.get("COMSPEC", "cmd.exe") args = comspec + " /c " + args # determine if we can create create a job canCreateJob = winprocess.CanCreateJobObject() # Ensure we write a warning message if we are falling back if not canCreateJob and not self._ignore_children: # We can't create job objects AND the user wanted us to # Warn the user about this. print >> sys.stderr, "ProcessManager UNABLE to use job objects to manage child processes" # set process creation flags creationflags |= winprocess.CREATE_SUSPENDED creationflags |= winprocess.CREATE_UNICODE_ENVIRONMENT if canCreateJob: creationflags |= winprocess.CREATE_BREAKAWAY_FROM_JOB else: # Since we've warned, we just log info here to inform you # of the consequence of setting ignore_children = True print "ProcessManager NOT managing child processes" # create the process hp, ht, pid, tid = winprocess.CreateProcess( executable, args, None, None, # No special security 1, # Must inherit handles! creationflags, winprocess.EnvironmentBlock(env), cwd, startupinfo) self._child_created = True self._handle = hp self._thread = ht self.pid = pid self.tid = tid if not self._ignore_children and canCreateJob: try: # We create a new job for this process, so that we can kill # the process and any sub-processes # Create the IO Completion Port self._io_port = winprocess.CreateIoCompletionPort() self._job = winprocess.CreateJobObject() # Now associate the io comp port and the job object joacp = JOBOBJECT_ASSOCIATE_COMPLETION_PORT(winprocess.COMPKEY_JOBOBJECT, self._io_port) winprocess.SetInformationJobObject(self._job, JobObjectAssociateCompletionPortInformation, addressof(joacp), sizeof(joacp) ) # Allow subprocesses to break away from us - necessary for # flash with protected mode jbli = JOBOBJECT_BASIC_LIMIT_INFORMATION( c_longlong(0), # per process time limit (ignored) c_longlong(0), # per job user time limit (ignored) winprocess.JOB_OBJECT_LIMIT_BREAKAWAY_OK, 0, # min working set (ignored) 0, # max working set (ignored) 0, # active process limit (ignored) None, # affinity (ignored) 0, # Priority class (ignored) 0, # Scheduling class (ignored) ) iocntr = IO_COUNTERS() jeli = JOBOBJECT_EXTENDED_LIMIT_INFORMATION( jbli, # basic limit info struct iocntr, # io_counters (ignored) 0, # process mem limit (ignored) 0, # job mem limit (ignored) 0, # peak process limit (ignored) 0) # peak job limit (ignored) winprocess.SetInformationJobObject(self._job, JobObjectExtendedLimitInformation, addressof(jeli), sizeof(jeli) ) # Assign the job object to the process winprocess.AssignProcessToJobObject(self._job, int(hp)) # It's overkill, but we use Queue to signal between threads # because it handles errors more gracefully than event or condition. self._process_events = Queue() # Spin up our thread for managing the IO Completion Port self._procmgrthread = threading.Thread(target = self._procmgr) except: print >> sys.stderr, """Exception trying to use job objects; falling back to not using job objects for managing child processes""" tb = traceback.format_exc() print >> sys.stderr, tb # Ensure no dangling handles left behind self._cleanup_job_io_port() else: self._job = None winprocess.ResumeThread(int(ht)) if getattr(self, '_procmgrthread', None): self._procmgrthread.start() ht.Close() for i in (p2cread, c2pwrite, errwrite): if i is not None: i.Close() # Windows Process Manager - watches the IO Completion Port and # keeps track of child processes def _procmgr(self): if not (self._io_port) or not (self._job): return try: self._poll_iocompletion_port() except KeyboardInterrupt: raise KeyboardInterrupt def _poll_iocompletion_port(self): # Watch the IO Completion port for status self._spawned_procs = {} countdowntokill = 0 if MOZPROCESS_DEBUG: print "DBG::MOZPROC Self.pid value is: %s" % self.pid while True: msgid = c_ulong(0) compkey = c_ulong(0) pid = c_ulong(0) portstatus = winprocess.GetQueuedCompletionStatus(self._io_port, byref(msgid), byref(compkey), byref(pid), 5000) # If the countdowntokill has been activated, we need to check # if we should start killing the children or not. if countdowntokill != 0: diff = datetime.now() - countdowntokill # Arbitrarily wait 3 minutes for windows to get its act together # Windows sometimes takes a small nap between notifying the # IO Completion port and actually killing the children, and we # don't want to mistake that situation for the situation of an unexpected # parent abort (which is what we're looking for here). if diff.seconds > self.MAX_IOCOMPLETION_PORT_NOTIFICATION_DELAY: print >> sys.stderr, "Parent process %s exited with children alive:" % self.pid print >> sys.stderr, "PIDS: %s" % ', '.join([str(i) for i in self._spawned_procs]) print >> sys.stderr, "Attempting to kill them..." self.kill() self._process_events.put({self.pid: 'FINISHED'}) if not portstatus: # Check to see what happened errcode = winprocess.GetLastError() if errcode == winprocess.ERROR_ABANDONED_WAIT_0: # Then something has killed the port, break the loop print >> sys.stderr, "IO Completion Port unexpectedly closed" break elif errcode == winprocess.WAIT_TIMEOUT: # Timeouts are expected, just keep on polling continue else: print >> sys.stderr, "Error Code %s trying to query IO Completion Port, exiting" % errcode raise WinError(errcode) break if compkey.value == winprocess.COMPKEY_TERMINATE.value: if MOZPROCESS_DEBUG: print "DBG::MOZPROC compkeyterminate detected" # Then we're done break # Check the status of the IO Port and do things based on it if compkey.value == winprocess.COMPKEY_JOBOBJECT.value: if msgid.value == winprocess.JOB_OBJECT_MSG_ACTIVE_PROCESS_ZERO: # No processes left, time to shut down # Signal anyone waiting on us that it is safe to shut down if MOZPROCESS_DEBUG: print "DBG::MOZPROC job object msg active processes zero" self._process_events.put({self.pid: 'FINISHED'}) break elif msgid.value == winprocess.JOB_OBJECT_MSG_NEW_PROCESS: # New Process started # Add the child proc to our list in case our parent flakes out on us # without killing everything. if pid.value != self.pid: self._spawned_procs[pid.value] = 1 if MOZPROCESS_DEBUG: print "DBG::MOZPROC new process detected with pid value: %s" % pid.value elif msgid.value == winprocess.JOB_OBJECT_MSG_EXIT_PROCESS: if MOZPROCESS_DEBUG: print "DBG::MOZPROC process id %s exited normally" % pid.value # One process exited normally if pid.value == self.pid and len(self._spawned_procs) > 0: # Parent process dying, start countdown timer countdowntokill = datetime.now() elif pid.value in self._spawned_procs: # Child Process died remove from list del(self._spawned_procs[pid.value]) elif msgid.value == winprocess.JOB_OBJECT_MSG_ABNORMAL_EXIT_PROCESS: # One process existed abnormally if MOZPROCESS_DEBUG: print "DBG::MOZPROC process id %s existed abnormally" % pid.value if pid.value == self.pid and len(self._spawned_procs) > 0: # Parent process dying, start countdown timer countdowntokill = datetime.now() elif pid.value in self._spawned_procs: # Child Process died remove from list del self._spawned_procs[pid.value] else: # We don't care about anything else if MOZPROCESS_DEBUG: print "DBG::MOZPROC We got a message %s" % msgid.value pass def _wait(self): # First, check to see if the process is still running if self._handle: self.returncode = winprocess.GetExitCodeProcess(self._handle) else: # Dude, the process is like totally dead! return self.returncode # Python 2.5 uses isAlive versus is_alive use the proper one threadalive = False if hasattr(self, "_procmgrthread"): if hasattr(self._procmgrthread, 'is_alive'): threadalive = self._procmgrthread.is_alive() else: threadalive = self._procmgrthread.isAlive() if self._job and threadalive: # Then we are managing with IO Completion Ports # wait on a signal so we know when we have seen the last # process come through. # We use queues to synchronize between the thread and this # function because events just didn't have robust enough error # handling on pre-2.7 versions err = None try: # timeout is the max amount of time the procmgr thread will wait for # child processes to shutdown before killing them with extreme prejudice. item = self._process_events.get(timeout=self.MAX_IOCOMPLETION_PORT_NOTIFICATION_DELAY + self.MAX_PROCESS_KILL_DELAY) if item[self.pid] == 'FINISHED': self._process_events.task_done() except: err = "IO Completion Port failed to signal process shutdown" # Either way, let's try to get this code if self._handle: self.returncode = winprocess.GetExitCodeProcess(self._handle) self._cleanup() if err is not None: raise OSError(err) else: # Not managing with job objects, so all we can reasonably do # is call waitforsingleobject and hope for the best if MOZPROCESS_DEBUG and not self._ignore_children: print "DBG::MOZPROC NOT USING JOB OBJECTS!!!" # First, make sure we have not already ended if self.returncode != winprocess.STILL_ACTIVE: self._cleanup() return self.returncode rc = None if self._handle: rc = winprocess.WaitForSingleObject(self._handle, -1) if rc == winprocess.WAIT_TIMEOUT: # The process isn't dead, so kill it print "Timed out waiting for process to close, attempting TerminateProcess" self.kill() elif rc == winprocess.WAIT_OBJECT_0: # We caught WAIT_OBJECT_0, which indicates all is well print "Single process terminated successfully" self.returncode = winprocess.GetExitCodeProcess(self._handle) else: # An error occured we should probably throw rc = winprocess.GetLastError() if rc: raise WinError(rc) self._cleanup() return self.returncode def _cleanup_job_io_port(self): """ Do the job and IO port cleanup separately because there are cases where we want to clean these without killing _handle (i.e. if we fail to create the job object in the first place) """ if getattr(self, '_job') and self._job != winprocess.INVALID_HANDLE_VALUE: self._job.Close() self._job = None else: # If windows already freed our handle just set it to none # (saw this intermittently while testing) self._job = None if getattr(self, '_io_port', None) and self._io_port != winprocess.INVALID_HANDLE_VALUE: self._io_port.Close() self._io_port = None else: self._io_port = None if getattr(self, '_procmgrthread', None): self._procmgrthread = None def _cleanup(self): self._cleanup_job_io_port() if self._thread and self._thread != winprocess.INVALID_HANDLE_VALUE: self._thread.Close() self._thread = None else: self._thread = None if self._handle and self._handle != winprocess.INVALID_HANDLE_VALUE: self._handle.Close() self._handle = None else: self._handle = None elif isPosix: def _wait(self): """ Haven't found any reason to differentiate between these platforms so they all use the same wait callback. If it is necessary to craft different styles of wait, then a new _wait method could be easily implemented. """ if not self._ignore_children: try: # os.waitpid return value: # > [...] a tuple containing its pid and exit status # > indication: a 16-bit number, whose low byte is the # > signal number that killed the process, and whose # > high byte is the exit status (if the signal number # > is zero) # - http://docs.python.org/2/library/os.html#os.wait status = os.waitpid(self.pid, 0)[1] # For consistency, format status the same as subprocess' # returncode attribute if status > 255: return status >> 8 return -status except OSError, e: if getattr(e, "errno", None) != 10: # Error 10 is "no child process", which could indicate normal # close print >> sys.stderr, "Encountered error waiting for pid to close: %s" % e raise return 0 else: # For non-group wait, call base class subprocess.Popen.wait(self) return self.returncode def _cleanup(self): pass else: # An unrecognized platform, we will call the base class for everything print >> sys.stderr, "Unrecognized platform, process groups may not be managed properly" def _wait(self): self.returncode = subprocess.Popen.wait(self) return self.returncode def _cleanup(self): pass def __init__(self, cmd, args=None, cwd=None, env=None, ignore_children = False, kill_on_timeout = True, processOutputLine=(), onTimeout=(), onFinish=(), **kwargs): self.cmd = cmd self.args = args self.cwd = cwd self.didTimeout = False self._ignore_children = ignore_children self._kill_on_timeout = kill_on_timeout self.keywordargs = kwargs self.outThread = None self.read_buffer = '' if env is None: env = os.environ.copy() self.env = env # handlers self.processOutputLineHandlers = list(processOutputLine) self.onTimeoutHandlers = list(onTimeout) self.onFinishHandlers = list(onFinish) # It is common for people to pass in the entire array with the cmd and # the args together since this is how Popen uses it. Allow for that. if isinstance(self.cmd, list): if self.args != None: raise TypeError("cmd and args must not both be lists") (self.cmd, self.args) = (self.cmd[0], self.cmd[1:]) elif self.args is None: self.args = [] @property def timedOut(self): """True if the process has timed out.""" return self.didTimeout @property def commandline(self): """the string value of the command line (command + args)""" return subprocess.list2cmdline([self.cmd] + self.args) def run(self, timeout=None, outputTimeout=None): """ Starts the process. If timeout is not None, the process will be allowed to continue for that number of seconds before being killed. If the process is killed due to a timeout, the onTimeout handler will be called. If outputTimeout is not None, the process will be allowed to continue for that number of seconds without producing any output before being killed. """ self.didTimeout = False self.startTime = datetime.now() # default arguments args = dict(stdout=subprocess.PIPE, stderr=subprocess.STDOUT, cwd=self.cwd, env=self.env, ignore_children=self._ignore_children) # build process arguments args.update(self.keywordargs) # launch the process self.proc = self.Process([self.cmd] + self.args, **args) self.processOutput(timeout=timeout, outputTimeout=outputTimeout) def kill(self, sig=None): """ Kills the managed process. If you created the process with 'ignore_children=False' (the default) then it will also also kill all child processes spawned by it. If you specified 'ignore_children=True' when creating the process, only the root process will be killed. Note that this does not manage any state, save any output etc, it immediately kills the process. :param sig: Signal used to kill the process, defaults to SIGKILL (has no effect on Windows) """ try: return self.proc.kill(sig=sig) except AttributeError: # Try to print a relevant error message. if not self.proc: print >> sys.stderr, "Unable to kill Process because call to ProcessHandler constructor failed." else: raise def readWithTimeout(self, f, timeout): """ Try to read a line of output from the file object *f*. *f* must be a pipe, like the *stdout* member of a subprocess.Popen object created with stdout=PIPE. If no output is received within *timeout* seconds, return a blank line. Returns a tuple (line, did_timeout), where *did_timeout* is True if the read timed out, and False otherwise. """ # Calls a private member because this is a different function based on # the OS return self._readWithTimeout(f, timeout) def processOutputLine(self, line): """Called for each line of output that a process sends to stdout/stderr.""" for handler in self.processOutputLineHandlers: handler(line) def onTimeout(self): """Called when a process times out.""" for handler in self.onTimeoutHandlers: handler() def onFinish(self): """Called when a process finishes without a timeout.""" for handler in self.onFinishHandlers: handler() def processOutput(self, timeout=None, outputTimeout=None): """ Handle process output until the process terminates or times out. If timeout is not None, the process will be allowed to continue for that number of seconds before being killed. If outputTimeout is not None, the process will be allowed to continue for that number of seconds without producing any output before being killed. """ def _processOutput(): self.didTimeout = False logsource = self.proc.stdout lineReadTimeout = None if timeout: lineReadTimeout = timeout - (datetime.now() - self.startTime).seconds elif outputTimeout: lineReadTimeout = outputTimeout (lines, self.didTimeout) = self.readWithTimeout(logsource, lineReadTimeout) while lines != "": for line in lines.splitlines(): self.processOutputLine(line.rstrip()) if self.didTimeout: break if timeout: lineReadTimeout = timeout - (datetime.now() - self.startTime).seconds (lines, self.didTimeout) = self.readWithTimeout(logsource, lineReadTimeout) if self.didTimeout: if self._kill_on_timeout: self.proc.kill() self.onTimeout() else: self.onFinish() if not hasattr(self, 'proc'): self.run() if not self.outThread: self.outThread = threading.Thread(target=_processOutput) self.outThread.daemon = True self.outThread.start() def wait(self, timeout=None): """ Waits until all output has been read and the process is terminated. If timeout is not None, will return after timeout seconds. This timeout only causes the wait function to return and does not kill the process. Returns the process' exit code. A None value indicates the process hasn't terminated yet. A negative value -N indicates the process was killed by signal N (Unix only). """ if self.outThread: # Thread.join() blocks the main thread until outThread is finished # wake up once a second in case a keyboard interrupt is sent count = 0 while self.outThread.isAlive(): self.outThread.join(timeout=1) count += 1 if timeout and count > timeout: return None return self.proc.wait() # TODO Remove this method when consumers have been fixed def waitForFinish(self, timeout=None): print >> sys.stderr, "MOZPROCESS WARNING: ProcessHandler.waitForFinish() is deprecated, " \ "use ProcessHandler.wait() instead" return self.wait(timeout=timeout) ### Private methods from here on down. Thar be dragons. if isWin: # Windows Specific private functions are defined in this block PeekNamedPipe = ctypes.windll.kernel32.PeekNamedPipe GetLastError = ctypes.windll.kernel32.GetLastError def _readWithTimeout(self, f, timeout): if timeout is None: # shortcut to allow callers to pass in "None" for no timeout. return (f.readline(), False) x = msvcrt.get_osfhandle(f.fileno()) l = ctypes.c_long() done = time.time() + timeout while time.time() < done: if self.PeekNamedPipe(x, None, 0, None, ctypes.byref(l), None) == 0: err = self.GetLastError() if err == 38 or err == 109: # ERROR_HANDLE_EOF || ERROR_BROKEN_PIPE return ('', False) else: raise OSError("readWithTimeout got error: %d", err) if l.value > 0: # we're assuming that the output is line-buffered, # which is not unreasonable return (f.readline(), False) time.sleep(0.01) return ('', True) else: # Generic def _readWithTimeout(self, f, timeout): while True: try: (r, w, e) = select.select([f], [], [], timeout) except: # return a blank line return ('', True) if len(r) == 0: return ('', True) output = os.read(f.fileno(), 4096) if not output: output = self.read_buffer self.read_buffer = '' return (output, False) self.read_buffer += output if '\n' not in self.read_buffer: time.sleep(0.01) continue tmp = self.read_buffer.split('\n') lines, self.read_buffer = tmp[:-1], tmp[-1] real_lines = [x for x in lines if x != ''] if not real_lines: time.sleep(0.01) continue break return ('\n'.join(lines), False) @property def pid(self): return self.proc.pid ### default output handlers ### these should be callables that take the output line def print_output(line): print line class StoreOutput(object): """accumulate stdout""" def __init__(self): self.output = [] def __call__(self, line): self.output.append(line) class LogOutput(object): """pass output to a file""" def __init__(self, filename): self.filename = filename self.file = None def __call__(self, line): if self.file is None: self.file = file(self.filename, 'a') self.file.write(line + '\n') self.file.flush() def __del__(self): if self.file is not None: self.file.close() ### front end class with the default handlers class ProcessHandler(ProcessHandlerMixin): """ Convenience class for handling processes with default output handlers. If no processOutputLine keyword argument is specified, write all output to stdout. Otherwise, the function specified by this argument will be called for each line of output; the output will not be written to stdout automatically. If storeOutput==True, the output produced by the process will be saved as self.output. If logfile is not None, the output produced by the process will be appended to the given file. """ def __init__(self, cmd, logfile=None, storeOutput=True, **kwargs): kwargs.setdefault('processOutputLine', []) # Print to standard output only if no outputline provided if not kwargs['processOutputLine']: kwargs['processOutputLine'].append(print_output) if logfile: logoutput = LogOutput(logfile) kwargs['processOutputLine'].append(logoutput) self.output = None if storeOutput: storeoutput = StoreOutput() self.output = storeoutput.output kwargs['processOutputLine'].append(storeoutput) ProcessHandlerMixin.__init__(self, cmd, **kwargs)