test_ok1/py/process/forkedfunc.py

109 lines
3.3 KiB
Python

"""
ForkedFunc provides a way to run a function in a forked process
and get at its return value, stdout and stderr output as well
as signals and exitstatusus.
XXX see if tempdir handling is sane
"""
import py
import os
import sys
import marshal
class ForkedFunc(object):
EXITSTATUS_EXCEPTION = 3
def __init__(self, fun, args=None, kwargs=None, nice_level=0):
if args is None:
args = []
if kwargs is None:
kwargs = {}
self.fun = fun
self.args = args
self.kwargs = kwargs
self.tempdir = tempdir = py.path.local.mkdtemp()
self.RETVAL = tempdir.ensure('retval')
self.STDOUT = tempdir.ensure('stdout')
self.STDERR = tempdir.ensure('stderr')
pid = os.fork()
if pid: # in parent process
self.pid = pid
else: # in child process
self._child(nice_level)
def _child(self, nice_level):
# right now we need to call a function, but first we need to
# map all IO that might happen
# make sure sys.stdout points to file descriptor one
sys.stdout = stdout = self.STDOUT.open('w')
sys.stdout.flush()
fdstdout = stdout.fileno()
if fdstdout != 1:
os.dup2(fdstdout, 1)
sys.stderr = stderr = self.STDERR.open('w')
fdstderr = stderr.fileno()
if fdstderr != 2:
os.dup2(fdstderr, 2)
retvalf = self.RETVAL.open("w")
EXITSTATUS = 0
try:
if nice_level:
os.nice(nice_level)
try:
retval = self.fun(*self.args, **self.kwargs)
retvalf.write(marshal.dumps(retval))
except:
excinfo = py.code.ExceptionInfo()
stderr.write(excinfo.exconly())
EXITSTATUS = self.EXITSTATUS_EXCEPTION
finally:
stdout.close()
stderr.close()
retvalf.close()
os.close(1)
os.close(2)
os._exit(EXITSTATUS)
def waitfinish(self, waiter=os.waitpid):
pid, systemstatus = waiter(self.pid, 0)
if systemstatus:
if os.WIFSIGNALED(systemstatus):
exitstatus = os.WTERMSIG(systemstatus) + 128
else:
exitstatus = os.WEXITSTATUS(systemstatus)
#raise ExecutionFailed(status, systemstatus, cmd,
# ''.join(out), ''.join(err))
else:
exitstatus = 0
signal = systemstatus & 0x7f
if not exitstatus and not signal:
retval = self.RETVAL.open()
try:
retval_data = retval.read()
finally:
retval.close()
retval = marshal.loads(retval_data)
else:
retval = None
stdout = self.STDOUT.read()
stderr = self.STDERR.read()
self._removetemp()
return Result(exitstatus, signal, retval, stdout, stderr)
def _removetemp(self):
if self.tempdir.check():
self.tempdir.remove()
def __del__(self):
self._removetemp()
class Result(object):
def __init__(self, exitstatus, signal, retval, stdout, stderr):
self.exitstatus = exitstatus
self.signal = signal
self.retval = retval
self.out = stdout
self.err = stderr