Inpection manhole for python applications. Connection is done via unix domain sockets.
Manhole is a python daemon thread that will accept unix domain socket connections and present the stacktraces for all threads and an interactive prompt.
Access to the socket is restricted to the application’s effective user id or root.
This is just like Twisted’s manhole. It’s simpler (no dependencies) and it only runs on Unix domain sockets (in contrast to Twisted’s manhole which can run on telnet or ssh).
Usage (you can put this in your django settings, wsgi app file, some module that’s always imported early etc):
import manhole manhole.install() # this will start the daemon thread # and now you start your app, eg: server.serve_forever()
Now in a shell you can do either of these:
netcat -U /tmp/manhole-1234 socat - unix-connect:/tmp/manhole-1234 socat readline unix-connect:/tmp/manhole-1234
$ nc -U /tmp/manhole-1234 Python 2.7.3 (default, Apr 10 2013, 06:20:15) [GCC 4.6.3] on linux2 Type "help", "copyright", "credits" or "license" for more information. (InteractiveConsole) >>> dir() ['__builtins__', 'dump_stacktraces', 'os', 'socket', 'sys', 'traceback'] >>> print 'foobar' foobar
- Uses unix domain sockets, only root or same effective user can connect.
- Current implementation runs a daemon thread that waits for connection.
- Compatible with apps that fork, reinstalls the Manhole thread after fork - had to monkeypatch os.fork/os.forkpty for this.
manhole.install(verbose=True, patch_fork=True, activate_on=None, sigmask=manhole.ALL_SIGNALS)
- verbose - set it to False to squelch the stderr ouput
- patch_fork - set it to False if you don’t want your os.fork and os.forkpy monkeypatched
- activate_on - set to "USR1", "USR2" or some other signal name, or a number if you want the Manhole thread to start when this signal is sent. This is desireable in case you don’t want the thread active all the time.
- sigmask - will set the signal mask to the given list (using signalfd.sigprocmask). No action is done if signalfd is not importable. NOTE: This is done so that the Manhole thread doesn’t steal any signals; Normally that is fine cause Python will force all the signal handling to be run in the main thread but signalfd doesn’t.
What happens when you actually connect to the socket
- Credentials are checked (if it’s same user or root)
- sys.__std*__/sys.std* are be redirected to the UDS
- Stacktraces for each thread are written to the UDS
- REPL is started so you can fiddle with the process
- Be compatible with eventlet/stackless (provide alternative implementation without thread)
- More configurable (chose what sys.__std*__/sys.std* to patch on connect time)
Not sure yet … maybe Python 2.6 and 2.7. Check Travis:
Coverage is wrong, must be a bug in coveralls, it should be at least 80%-90% depending whether you count branches or not.