def __enter__(self):
# Teach the first command to take input specially
self.commands[0].stdinSet = self.in_fd
last_command = self.commands[0]
# Connect all interior commands to one another via stdin/stdout
for command in self.commands[1:]:
last_command.start()
# Set large kernel buffering between pipeline
# participants.
pipebuf.set_buf_size(last_command.stdout.fileno())
command.stdinSet = last_command.stdout
last_command = command
# Teach the last command to spill output to out_fd rather than to
# its default, which is typically stdout.
assert last_command is self.commands[-1]
last_command.stdoutSet = self.out_fd
last_command.start()
stdin = self.commands[0].stdin
if stdin is not None:
self.stdin = pipebuf.NonBlockBufferedWriter(stdin)
else:
self.stdin = None
stdout = self.commands[-1].stdout
if stdout is not None:
self.stdout = pipebuf.NonBlockBufferedReader(stdout)
else:
self.stdout = None
return self
def popen_nonblock(*args, **kwargs):
"""
Create a process in the same way as popen_sp, but patch the file
descriptors so they can be accessed from Python/gevent
in a non-blocking manner.
"""
proc = popen_sp(*args, **kwargs)
if proc.stdin:
proc.stdin = pipebuf.NonBlockBufferedWriter(proc.stdin)
if proc.stdout:
proc.stdout = pipebuf.NonBlockBufferedReader(proc.stdout)
if proc.stderr:
proc.stderr = pipebuf.NonBlockBufferedReader(proc.stderr)
return proc
def __enter__(self):
# Ensure there is at least one step in the pipeline.
#
# If all optional features are turned off, the pipeline will
# be completely empty and crash.
if len(self.commands) == 0:
self.commands.append(CatFilter())
# Teach the first command to take input specially
self.commands[0].stdinSet = self.in_fd
last_command = self.commands[0]
# Connect all interior commands to one another via stdin/stdout
for command in self.commands[1:]:
last_command.start()
# Set large kernel buffering between pipeline
# participants.
pipebuf.set_buf_size(last_command.stdout.fileno())
command.stdinSet = last_command.stdout
last_command = command
# Teach the last command to spill output to out_fd rather than to
# its default, which is typically stdout.
assert last_command is self.commands[-1]
last_command.stdoutSet = self.out_fd
last_command.start()
stdin = self.commands[0].stdin
if stdin is not None:
self.stdin = pipebuf.NonBlockBufferedWriter(stdin)
else:
self.stdin = None
stdout = self.commands[-1].stdout
if stdout is not None:
self.stdout = pipebuf.NonBlockBufferedReader(stdout)
else:
self.stdout = None
return self