gunicorn/gunicorn/workers/base.py

# -*- coding: utf-8 -
#
# This file is part of gunicorn released under the MIT license.
# See the NOTICE for more information.

from datetime import datetime
import os
import signal
import sys
import traceback


from gunicorn import util
from gunicorn.workers.workertmp import WorkerTmp
from gunicorn.http.errors import InvalidHeader, InvalidHeaderName, \
InvalidRequestLine, InvalidRequestMethod, InvalidHTTPVersion, \
LimitRequestLine, LimitRequestHeaders
from gunicorn.http.wsgi import default_environ, Response

class Worker(object):

    SIGNALS = map(
        lambda x: getattr(signal, "SIG%s" % x),
        "HUP QUIT INT TERM USR1 USR2 WINCH CHLD".split()
    )

    PIPE = []

    def __init__(self, age, ppid, socket, app, timeout, cfg, log):
        """\
        This is called pre-fork so it shouldn't do anything to the
        current process. If there's a need to make process wide
        changes you'll want to do that in ``self.init_process()``.
        """
        self.age = age
        self.ppid = ppid
        self.socket = socket
        self.app = app
        self.timeout = timeout
        self.cfg = cfg
        self.booted = False

        self.nr = 0
        self.max_requests = cfg.max_requests or sys.maxint
        self.alive = True
        self.log = log
        self.debug = cfg.debug
        self.address = self.socket.getsockname()
        self.tmp = WorkerTmp(cfg)

    def __str__(self):
        return "<Worker %s>" % self.pid

    @property
    def pid(self):
        return os.getpid()

    def notify(self):
        """\
        Your worker subclass must arrange to have this method called
        once every ``self.timeout`` seconds. If you fail in accomplishing
        this task, the master process will murder your workers.
        """
        self.tmp.notify()

    def run(self):
        """\
        This is the mainloop of a worker process. You should override
        this method in a subclass to provide the intended behaviour
        for your particular evil schemes.
        """
        raise NotImplementedError()

    def init_process(self):
        """\
        If you override this method in a subclass, the last statement
        in the function should be to call this method with
        super(MyWorkerClass, self).init_process() so that the ``run()``
        loop is initiated.
        """
        util.set_owner_process(self.cfg.uid, self.cfg.gid)

        # Reseed the random number generator
        util.seed()

        # For waking ourselves up
        self.PIPE = os.pipe()
        map(util.set_non_blocking, self.PIPE)
        map(util.close_on_exec, self.PIPE)

        # Prevent fd inherientence
        util.close_on_exec(self.socket)
        util.close_on_exec(self.tmp.fileno())

        self.log.close_on_exec()

        self.init_signals()

        self.wsgi = self.app.wsgi()

        # Enter main run loop
        self.booted = True
        self.run()

    def init_signals(self):
        map(lambda s: signal.signal(s, signal.SIG_DFL), self.SIGNALS)
        signal.signal(signal.SIGQUIT, self.handle_quit)
        signal.signal(signal.SIGTERM, self.handle_exit)
        signal.signal(signal.SIGINT, self.handle_exit)
        signal.signal(signal.SIGWINCH, self.handle_winch)
        signal.signal(signal.SIGUSR1, self.handle_usr1)
        # Don't let SIGQUIT and SIGUSR1 disturb active requests
        # by interrupting system calls
        if hasattr(signal, 'siginterrupt'):  # python >= 2.6
            signal.siginterrupt(signal.SIGQUIT, False)
            signal.siginterrupt(signal.SIGUSR1, False)

    def handle_usr1(self, sig, frame):
        self.log.reopen_files()

    def handle_quit(self, sig, frame):
        self.alive = False

    def handle_exit(self, sig, frame):
        self.alive = False
        sys.exit(0)

    def handle_error(self, req, client, addr, exc):
        request_start = datetime.now()
        if isinstance(exc, (InvalidRequestLine, InvalidRequestMethod,
            InvalidHTTPVersion, InvalidHeader, InvalidHeaderName,
            LimitRequestLine, LimitRequestHeaders,)):

            status_int = 400
            reason = "Bad Request"

            if isinstance(exc, InvalidRequestLine):
                mesg = "<p>Invalid Request Line '%s'</p>" % str(exc)
            elif isinstance(exc, InvalidRequestMethod):
                mesg = "<p>Invalid Method '%s'</p>" % str(exc)
            elif isinstance(exc, InvalidHTTPVersion):
                mesg = "<p>Invalid HTTP Version '%s'</p>" % str(exc)
            elif isinstance(exc, (InvalidHeaderName, InvalidHeader,)):
                mesg = "<p>Invalid Header '%s'</p>" % str(exc)
            elif isinstance(exc, LimitRequestLine):
                mesg = "<p>%s</p>" % str(exc)
            elif isinstance(exc, LimitRequestHeaders):
                mesg = "<p>Error parsing headers: '%s'</p>" % str(exc)

            self.log.debug("Invalid request from ip={ip}: {error}"\
                           "".format(ip=client.getpeername()[0],
                                     error=repr(exc),
                                    )
                          )
        else:
            self.log.exception("Error handling request")

            status_int = 500
            reason = "Internal Server Error"
            mesg = ""

        if req is not None:
            request_time = datetime.now() - request_start
            environ = default_environ(req, client, self.cfg)
            environ['REMOTE_ADDR'] = addr[0]
            environ['REMOTE_PORT'] = str(addr[1])
            resp = Response(req, client)
            resp.status = "%s %s" % (status_int, reason)
            resp.response_length = len(mesg)
            self.log.access(resp, req, environ, request_time)

        if self.debug:
            tb = traceback.format_exc()
            mesg += "<h2>Traceback:</h2>\n<pre>%s</pre>" % tb

        try:
            util.write_error(client, status_int, reason, mesg)
        except:
            self.log.warning("Failed to send error message.")

    def handle_winch(self, sig, fname):
        # Ignore SIGWINCH in worker. Fixes a crash on OpenBSD.
        return