gunicorn/gunicorn/workers/sync.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 errno
import os
import select
import socket
import ssl
import sys

import gunicorn.http as http
import gunicorn.http.wsgi as wsgi
import gunicorn.util as util
import gunicorn.workers.base as base
from gunicorn import six


class SyncWorker(base.Worker):

    def accept(self, listener):
        client, addr = listener.accept()
        client.setblocking(1)
        util.close_on_exec(client)
        self.handle(listener, client, addr)

    def wait(self, timeout):
        try:
            self.notify()
            ret = select.select(self.sockets, [], self.PIPE, timeout)
            if ret[0]:
                return ret[0]

        except select.error as e:
            if e.args[0] == errno.EINTR:
                return self.sockets
            if e.args[0] == errno.EBADF:
                if self.nr < 0:
                    return self.sockets
                else:
                    return False
            raise

    def is_parent_alive(self):
        # If our parent changed then we shut down.
        if self.ppid != os.getppid():
            self.log.info("Parent changed, shutting down: %s", self)
            return False
        return True

    def run_for_one(self, timeout):
        listener = self.sockets[0]
        while self.alive:
            self.notify()

            # Accept a connection. If we get an error telling us
            # that no connection is waiting we fall down to the
            # select which is where we'll wait for a bit for new
            # workers to come give us some love.
            try:
                self.accept(listener)
                # Keep processing clients until no one is waiting. This
                # prevents the need to select() for every client that we
                # process.
                continue

            except socket.error as e:
                if e.args[0] not in (errno.EAGAIN, errno.ECONNABORTED,
                        errno.EWOULDBLOCK):
                    raise

            if not self.is_parent_alive():
                return

            if not self.wait(timeout):
                return

    def run_for_multiple(self, timeout):
        while self.alive:
            self.notify()

            ready = self.wait(timeout)
            if not ready:
                return

            for listener in ready:
                try:
                    self.accept(listener)
                except socket.error as e:
                    if e.args[0] not in (errno.EAGAIN, errno.ECONNABORTED,
                            errno.EWOULDBLOCK):
                        raise

            if not self.is_parent_alive():
                return

    def run(self):
        # if no timeout is given the worker will never wait and will
        # use the CPU for nothing. This minimal timeout prevent it.
        timeout = self.timeout or 0.5

        # self.socket appears to lose its blocking status after
        # we fork in the arbiter. Reset it here.
        for s in self.sockets:
            s.setblocking(0)

        if len(self.sockets) > 1:
            self.run_for_multiple(timeout)
        else:
            self.run_for_one(timeout)

    def handle(self, listener, client, addr):
        req = None
        try:
            if self.cfg.is_ssl:
                client = ssl.wrap_socket(client, server_side=True,
                    **self.cfg.ssl_options)

            parser = http.RequestParser(self.cfg, client)
            req = six.next(parser)
            self.handle_request(listener, req, client, addr)
        except http.errors.NoMoreData as e:
            self.log.debug("Ignored premature client disconnection. %s", e)
        except StopIteration as e:
            self.log.debug("Closing connection. %s", e)
        except ssl.SSLError as e:
            if e.args[0] == ssl.SSL_ERROR_EOF:
                self.log.debug("ssl connection closed")
                client.close()
            else:
                self.log.debug("Error processing SSL request.")
                self.handle_error(req, client, addr, e)
        except socket.error as e:
            if e.args[0] not in (errno.EPIPE, errno.ECONNRESET):
                self.log.exception("Socket error processing request.")
            else:
                if e.args[0] == errno.ECONNRESET:
                    self.log.debug("Ignoring connection reset")
                else:
                    self.log.debug("Ignoring EPIPE")
        except Exception as e:
            self.handle_error(req, client, addr, e)
        finally:
            util.close(client)

    def handle_request(self, listener, req, client, addr):
        environ = {}
        resp = None
        try:
            self.cfg.pre_request(self, req)
            request_start = datetime.now()
            resp, environ = wsgi.create(req, client, addr,
                    listener.getsockname(), self.cfg)
            # Force the connection closed until someone shows
            # a buffering proxy that supports Keep-Alive to
            # the backend.
            resp.force_close()
            self.nr += 1
            if self.nr >= self.max_requests:
                self.log.info("Autorestarting worker after current request.")
                self.alive = False
            respiter = self.wsgi(environ, resp.start_response)
            try:
                if isinstance(respiter, environ['wsgi.file_wrapper']):
                    resp.write_file(respiter)
                else:
                    for item in respiter:
                        resp.write(item)
                resp.close()
                request_time = datetime.now() - request_start
                self.log.access(resp, req, environ, request_time)
            finally:
                if hasattr(respiter, "close"):
                    respiter.close()
        except socket.error:
            exc_info = sys.exc_info()
            # pass to next try-except level
            six.reraise(exc_info[0], exc_info[1], exc_info[2])
        except Exception:
            if resp and resp.headers_sent:
                # If the requests have already been sent, we should close the
                # connection to indicate the error.
                self.log.exception("Error handling request")
                try:
                    client.shutdown(socket.SHUT_RDWR)
                    client.close()
                except socket.error:
                    pass
                raise StopIteration()
            raise
        finally:
            try:
                self.cfg.post_request(self, req, environ, resp)
            except Exception:
                self.log.exception("Exception in post_request hook")