mercurial/hgweb/server.py

hgweb: skip logging ConnectionAbortedError

Not stacktracing on `ConnectionResetError` was added in 6bbb12cba5a8 (though it
was spelled differently for py2 support), but for some reason Windows
occasionally triggers a `ConnectionAbortedError` here across various *.t files
(notably `test-archive.t` and `test-lfs-serve-access.t`, but there are others).
The payload that fails to send seems to be the html that describes the error to
the client, so I suspect some code is seeing the error status code and closing
the connection before the server gets to write this html.  So don't log it, for
test stability- nothing we can do anyway.

FWIW, the CPython implementation of wsgihander specifically ignores these two
errors, plus `BrokenPipeError`, with a comment that "we expect the client to
close the connection abruptly from time to time"[1].  The `BrokenPipeError` is
swallowed a level up in `do_write()`, and avoids writing the response following
this stacktrace.  I'm puzzled why a response is being written after these
connection errors are detected- the CPython code referenced doesn't, and the
connection is now broken at this point.  Perhaps these errors should both be
handled with the `BrokenPipeError` after the freeze.

(The refactoring away from py2 compat may not be desireable in the freeze, but
this is much easier to read, and obviously correct given the referenced CPython
code.)

I suspect this is what 6bceecb28806 was attempting to fix, but it wasn't
specific about the sporadic errors it was seeing.

[1] https://github.com/python/cpython/blob/b2eaa75b176e07730215d76d8dce4d63fb493391/Lib/wsgiref/handlers.py#L139

# hgweb/server.py - The standalone hg web server.
#
# Copyright 21 May 2005 - (c) 2005 Jake Edge <[e-mail]>
# Copyright 2005-2007 Olivia Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import annotations

import os
import socket
import sys
import traceback
import wsgiref.validate

from ..i18n import _
from ..pycompat import (
    open,
)

from .. import (
    encoding,
    error,
    pycompat,
    util,
)
from ..utils import (
    urlutil,
)

httpservermod = util.httpserver
socketserver = util.socketserver
urlerr = util.urlerr
urlreq = util.urlreq

from . import common


def _splitURI(uri):
    """Return path and query that has been split from uri

    Just like CGI environment, the path is unquoted, the query is
    not.
    """
    if '?' in uri:
        path, query = uri.split('?', 1)
    else:
        path, query = uri, r''
    return urlreq.unquote(path), query


class _error_logger:
    def __init__(self, handler):
        self.handler = handler

    def flush(self):
        pass

    def write(self, str):
        self.writelines(str.split(b'\n'))

    def writelines(self, seq):
        for msg in seq:
            self.handler.log_error("HG error:  %s", encoding.strfromlocal(msg))


class _httprequesthandler(httpservermod.basehttprequesthandler):
    url_scheme = b'http'

    @staticmethod
    def preparehttpserver(httpserver, ui):
        """Prepare .socket of new HTTPServer instance"""

    def __init__(self, *args, **kargs):
        self.protocol_version = r'HTTP/1.1'
        httpservermod.basehttprequesthandler.__init__(self, *args, **kargs)

    def _log_any(self, fp, format, *args):
        fp.write(
            pycompat.sysbytes(
                r"%s - - [%s] %s"
                % (
                    self.client_address[0],
                    self.log_date_time_string(),
                    format % args,
                )
            )
            + b'\n'
        )
        fp.flush()

    def log_error(self, format, *args):
        self._log_any(self.server.errorlog, format, *args)

    def log_message(self, format, *args):
        self._log_any(self.server.accesslog, format, *args)

    def log_request(self, code='-', size='-'):
        xheaders = []
        if hasattr(self, 'headers'):
            xheaders = [
                h for h in self.headers.items() if h[0].startswith('x-')
            ]
        self.log_message(
            '"%s" %s %s%s',
            self.requestline,
            str(code),
            str(size),
            ''.join([' %s:%s' % h for h in sorted(xheaders)]),
        )

    def do_write(self):
        try:
            self.do_hgweb()
        except BrokenPipeError:
            pass

    def do_POST(self):
        try:
            self.do_write()
        except Exception as e:
            # I/O below could raise another exception. So log the original
            # exception first to ensure it is recorded.
            if not (
                isinstance(e, (ConnectionResetError, ConnectionAbortedError))
            ):
                tb = "".join(traceback.format_exception(*sys.exc_info()))
                # We need a native-string newline to poke in the log
                # message, because we won't get a newline when using an
                # r-string. This is the easy way out.
                newline = chr(10)
                self.log_error(
                    r"Exception happened during processing "
                    "request '%s':%s%s",
                    self.path,
                    newline,
                    tb,
                )

            self._start_response("500 Internal Server Error", [])
            self._write(b"Internal Server Error")
            self._done()

    def do_PUT(self):
        self.do_POST()

    def do_GET(self):
        self.do_POST()

    def do_HEAD(self):
        self.do_POST()

    def do_hgweb(self):
        self.sent_headers = False
        path, query = _splitURI(self.path)

        # Ensure the slicing of path below is valid
        if path != self.server.prefix and not path.startswith(
            self.server.prefix + b'/'
        ):
            self._start_response(pycompat.strurl(common.statusmessage(404)), [])
            if self.command == 'POST':
                # Paranoia: tell the client we're going to close the
                # socket so they don't try and reuse a socket that
                # might have a POST body waiting to confuse us. We do
                # this by directly munging self.saved_headers because
                # self._start_response ignores Connection headers.
                self.saved_headers = [('Connection', 'Close')]
            self._write(b"Not Found")
            self._done()
            return

        env = {}
        env['GATEWAY_INTERFACE'] = 'CGI/1.1'
        env['REQUEST_METHOD'] = self.command
        env['SERVER_NAME'] = self.server.server_name
        env['SERVER_PORT'] = str(self.server.server_port)
        env['REQUEST_URI'] = self.path
        env['SCRIPT_NAME'] = pycompat.sysstr(self.server.prefix)
        env['PATH_INFO'] = pycompat.sysstr(path[len(self.server.prefix) :])
        env['REMOTE_HOST'] = self.client_address[0]
        env['REMOTE_ADDR'] = self.client_address[0]
        env['QUERY_STRING'] = query or ''

        if self.headers.get_content_type() is None:
            env['CONTENT_TYPE'] = self.headers.get_default_type()
        else:
            env['CONTENT_TYPE'] = self.headers.get_content_type()
        length = self.headers.get('content-length')
        if length:
            env['CONTENT_LENGTH'] = length
        for header in [
            h
            for h in self.headers.keys()
            if h.lower() not in ('content-type', 'content-length')
        ]:
            hkey = 'HTTP_' + header.replace('-', '_').upper()
            hval = self.headers.get(header)
            hval = hval.replace('\n', '').strip()
            if hval:
                env[hkey] = hval
        env['SERVER_PROTOCOL'] = self.request_version
        env['wsgi.version'] = (1, 0)
        env['wsgi.url_scheme'] = pycompat.sysstr(self.url_scheme)
        if env.get('HTTP_EXPECT', '').lower() == '100-continue':
            self.rfile = common.continuereader(self.rfile, self.wfile.write)

        env['wsgi.input'] = self.rfile
        env['wsgi.errors'] = _error_logger(self)
        env['wsgi.multithread'] = isinstance(
            self.server, socketserver.ThreadingMixIn
        )
        if hasattr(socketserver, 'ForkingMixIn'):
            env['wsgi.multiprocess'] = isinstance(
                self.server, socketserver.ForkingMixIn
            )
        else:
            env['wsgi.multiprocess'] = False

        env['wsgi.run_once'] = 0

        wsgiref.validate.check_environ(env)

        self.saved_status = None
        self.saved_headers = []
        self.length = None
        self._chunked = None
        for chunk in self.server.application(env, self._start_response):
            self._write(chunk)
        if not self.sent_headers:
            self.send_headers()
        self._done()

    def send_headers(self):
        if not self.saved_status:
            raise AssertionError(
                b"Sending headers before start_response() called"
            )
        saved_status = self.saved_status.split(None, 1)
        saved_status[0] = int(saved_status[0])
        self.send_response(*saved_status)
        self.length = None
        self._chunked = False
        for h in self.saved_headers:
            self.send_header(*h)
            if h[0].lower() == 'content-length':
                self.length = int(h[1])
        if (
            self.length is None
            and saved_status[0] != common.HTTP_NOT_MODIFIED
            and self.command != 'HEAD'
        ):
            self._chunked = (
                not self.close_connection and self.request_version == 'HTTP/1.1'
            )
            if self._chunked:
                self.send_header('Transfer-Encoding', 'chunked')
            else:
                self.send_header('Connection', 'close')
        self.end_headers()
        self.sent_headers = True

    def _start_response(self, http_status, headers, exc_info=None):
        assert isinstance(http_status, str)
        code, msg = http_status.split(None, 1)
        code = int(code)
        self.saved_status = http_status
        bad_headers = ('connection', 'transfer-encoding')
        self.saved_headers = [
            h for h in headers if h[0].lower() not in bad_headers
        ]
        return self._write

    def _write(self, data):
        if not self.saved_status:
            raise AssertionError(b"data written before start_response() called")
        elif not self.sent_headers:
            self.send_headers()
        if self.length is not None:
            if len(data) > self.length:
                raise AssertionError(
                    b"Content-length header sent, but more "
                    b"bytes than specified are being written."
                )
            self.length = self.length - len(data)
        elif self._chunked and data:
            data = b'%x\r\n%s\r\n' % (len(data), data)
        self.wfile.write(data)
        self.wfile.flush()

    def _done(self):
        if self._chunked:
            self.wfile.write(b'0\r\n\r\n')
            self.wfile.flush()

    def version_string(self):
        if self.server.serverheader:
            return encoding.strfromlocal(self.server.serverheader)
        return httpservermod.basehttprequesthandler.version_string(self)


class _httprequesthandlerssl(_httprequesthandler):
    """HTTPS handler based on Python's ssl module"""

    url_scheme = b'https'

    @staticmethod
    def preparehttpserver(httpserver, ui):
        try:
            from .. import sslutil

            sslutil.wrapserversocket
        except ImportError:
            raise error.Abort(_(b"SSL support is unavailable"))

        certfile = ui.config(b'web', b'certificate')

        # These config options are currently only meant for testing. Use
        # at your own risk.
        cafile = ui.config(b'devel', b'servercafile')
        reqcert = ui.configbool(b'devel', b'serverrequirecert')

        httpserver.socket = sslutil.wrapserversocket(
            httpserver.socket,
            ui,
            certfile=certfile,
            cafile=cafile,
            requireclientcert=reqcert,
        )

    def setup(self):
        self.connection = self.request
        self.rfile = self.request.makefile("rb", self.rbufsize)
        self.wfile = self.request.makefile("wb", self.wbufsize)


try:
    import threading

    threading.active_count()  # silence pyflakes and bypass demandimport
    _mixin = socketserver.ThreadingMixIn
except ImportError:
    if hasattr(os, "fork"):
        _mixin = socketserver.ForkingMixIn
    else:

        class _mixin:
            pass


def openlog(opt, default):
    if opt and opt != b'-':
        return open(opt, b'ab')
    return default


class MercurialHTTPServer(_mixin, httpservermod.httpserver, object):
    # SO_REUSEADDR has broken semantics on windows
    if pycompat.iswindows:
        allow_reuse_address = 0

    def __init__(self, ui, app, addr, handler, **kwargs):
        httpservermod.httpserver.__init__(self, addr, handler, **kwargs)
        self.daemon_threads = True
        self.application = app

        handler.preparehttpserver(self, ui)

        prefix = ui.config(b'web', b'prefix')
        if prefix:
            prefix = b'/' + prefix.strip(b'/')
        self.prefix = prefix

        alog = openlog(ui.config(b'web', b'accesslog'), ui.fout)
        elog = openlog(ui.config(b'web', b'errorlog'), ui.ferr)
        self.accesslog = alog
        self.errorlog = elog

        self.addr, self.port = self.socket.getsockname()[0:2]
        self.fqaddr = self.server_name

        self.serverheader = ui.config(b'web', b'server-header')


class IPv6HTTPServer(MercurialHTTPServer):
    address_family = getattr(socket, 'AF_INET6', None)

    def __init__(self, *args, **kwargs):
        if self.address_family is None:
            raise error.RepoError(_(b'IPv6 is not available on this system'))
        super(IPv6HTTPServer, self).__init__(*args, **kwargs)


def create_server(ui, app):
    if ui.config(b'web', b'certificate'):
        handler = _httprequesthandlerssl
    else:
        handler = _httprequesthandler

    if ui.configbool(b'web', b'ipv6'):
        cls = IPv6HTTPServer
    else:
        cls = MercurialHTTPServer

    # ugly hack due to python issue5853 (for threaded use)
    import mimetypes

    mimetypes.init()

    address = ui.config(b'web', b'address')
    port = urlutil.getport(ui.config(b'web', b'port'))
    try:
        return cls(ui, app, (address, port), handler)
    except socket.error as inst:
        raise error.Abort(
            _(b"cannot start server at '%s:%d': %s")
            % (address, port, encoding.strtolocal(inst.args[1]))
        )