4 # Copyright (C) 2007, 2008, 2010 Google Inc.
6 # This program is free software; you can redistribute it and/or modify
7 # it under the terms of the GNU General Public License as published by
8 # the Free Software Foundation; either version 2 of the License, or
9 # (at your option) any later version.
11 # This program is distributed in the hope that it will be useful, but
12 # WITHOUT ANY WARRANTY; without even the implied warranty of
13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 # General Public License for more details.
16 # You should have received a copy of the GNU General Public License
17 # along with this program; if not, write to the Free Software
18 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
21 """HTTP server module.
34 from ganeti import http
35 from ganeti import utils
36 from ganeti import netutils
39 WEEKDAYNAME = ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"]
41 "Jan", "Feb", "Mar", "Apr", "May", "Jun",
42 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
44 # Default error message
45 DEFAULT_ERROR_CONTENT_TYPE = "text/html"
46 DEFAULT_ERROR_MESSAGE = """\
49 <title>Error response</title>
52 <h1>Error response</h1>
53 <p>Error code %(code)d.
54 <p>Message: %(message)s.
55 <p>Error code explanation: %(code)s = %(explain)s.
61 def _DateTimeHeader(gmnow=None):
62 """Return the current date and time formatted for a message header.
64 The time MUST be in the GMT timezone.
69 (year, month, day, hh, mm, ss, wd, _, _) = gmnow
70 return ("%s, %02d %3s %4d %02d:%02d:%02d GMT" %
71 (WEEKDAYNAME[wd], day, MONTHNAME[month], year, hh, mm, ss))
74 class _HttpServerRequest(object):
75 """Data structure for HTTP request on server side.
78 def __init__(self, method, path, headers, body):
80 self.request_method = method
81 self.request_path = path
82 self.request_headers = headers
83 self.request_body = body
86 self.resp_headers = {}
88 # Private data for request handler (useful in combination with
93 status = ["%s.%s" % (self.__class__.__module__, self.__class__.__name__),
94 self.request_method, self.request_path,
95 "headers=%r" % str(self.request_headers),
96 "body=%r" % (self.request_body, )]
98 return "<%s at %#x>" % (" ".join(status), id(self))
101 class _HttpServerToClientMessageWriter(http.HttpMessageWriter):
102 """Writes an HTTP response to client.
105 def __init__(self, sock, request_msg, response_msg, write_timeout):
106 """Writes the response to the client.
109 @param sock: Target socket
110 @type request_msg: http.HttpMessage
111 @param request_msg: Request message, required to determine whether
112 response may have a message body
113 @type response_msg: http.HttpMessage
114 @param response_msg: Response message
115 @type write_timeout: float
116 @param write_timeout: Write timeout for socket
119 self._request_msg = request_msg
120 self._response_msg = response_msg
121 http.HttpMessageWriter.__init__(self, sock, response_msg, write_timeout)
123 def HasMessageBody(self):
124 """Logic to detect whether response should contain a message body.
127 if self._request_msg.start_line:
128 request_method = self._request_msg.start_line.method
130 request_method = None
132 response_code = self._response_msg.start_line.code
134 # RFC2616, section 4.3: "A message-body MUST NOT be included in a request
135 # if the specification of the request method (section 5.1.1) does not allow
136 # sending an entity-body in requests"
138 # RFC2616, section 9.4: "The HEAD method is identical to GET except that
139 # the server MUST NOT return a message-body in the response."
141 # RFC2616, section 10.2.5: "The 204 response MUST NOT include a
142 # message-body [...]"
144 # RFC2616, section 10.3.5: "The 304 response MUST NOT contain a
145 # message-body, [...]"
147 return (http.HttpMessageWriter.HasMessageBody(self) and
148 (request_method is not None and
149 request_method != http.HTTP_HEAD) and
150 response_code >= http.HTTP_OK and
151 response_code not in (http.HTTP_NO_CONTENT,
152 http.HTTP_NOT_MODIFIED))
155 class _HttpClientToServerMessageReader(http.HttpMessageReader):
156 """Reads an HTTP request sent by client.
160 START_LINE_LENGTH_MAX = 4096
161 HEADER_LENGTH_MAX = 4096
163 def ParseStartLine(self, start_line):
164 """Parses the start line sent by client.
166 Example: "GET /index.html HTTP/1.1"
168 @type start_line: string
169 @param start_line: Start line
172 # Empty lines are skipped when reading
175 logging.debug("HTTP request: %s", start_line)
177 words = start_line.split()
180 [method, path, version] = words
181 if version[:5] != "HTTP/":
182 raise http.HttpBadRequest("Bad request version (%r)" % version)
185 base_version_number = version.split("/", 1)[1]
186 version_number = base_version_number.split(".")
188 # RFC 2145 section 3.1 says there can be only one "." and
189 # - major and minor numbers MUST be treated as
191 # - HTTP/2.4 is a lower version than HTTP/2.13, which in
192 # turn is lower than HTTP/12.3;
193 # - Leading zeros MUST be ignored by recipients.
194 if len(version_number) != 2:
195 raise http.HttpBadRequest("Bad request version (%r)" % version)
197 version_number = (int(version_number[0]), int(version_number[1]))
198 except (ValueError, IndexError):
199 raise http.HttpBadRequest("Bad request version (%r)" % version)
201 if version_number >= (2, 0):
202 raise http.HttpVersionNotSupported("Invalid HTTP Version (%s)" %
205 elif len(words) == 2:
206 version = http.HTTP_0_9
207 [method, path] = words
208 if method != http.HTTP_GET:
209 raise http.HttpBadRequest("Bad HTTP/0.9 request type (%r)" % method)
212 raise http.HttpBadRequest("Bad request syntax (%r)" % start_line)
214 return http.HttpClientToServerStartLine(method, path, version)
217 def HandleServerRequest(handler, req_msg):
218 """Calls the handler function for the current request.
221 handler_context = _HttpServerRequest(req_msg.start_line.method,
222 req_msg.start_line.path,
226 logging.debug("Handling request %r", handler_context)
230 # Authentication, etc.
231 handler.PreHandleRequest(handler_context)
233 # Call actual request handler
234 result = handler.HandleRequest(handler_context)
235 except (http.HttpException, KeyboardInterrupt, SystemExit):
237 except Exception, err:
238 logging.exception("Caught exception")
239 raise http.HttpInternalServerError(message=str(err))
241 logging.exception("Unknown exception")
242 raise http.HttpInternalServerError(message="Unknown error")
244 if not isinstance(result, basestring):
245 raise http.HttpError("Handler function didn't return string type")
247 return (http.HTTP_OK, handler_context.resp_headers, result)
249 # No reason to keep this any longer, even for exceptions
250 handler_context.private = None
253 class HttpServerRequestExecutor(object):
254 """Implements server side of HTTP.
256 This class implements the server side of HTTP. It's based on code of
257 Python's BaseHTTPServer, from both version 2.4 and 3k. It does not
258 support non-ASCII character encodings. Keep-alive connections are
262 # The default request version. This only affects responses up until
263 # the point where the request line is parsed, so it mainly decides what
264 # the client gets back when sending a malformed request line.
265 # Most web servers default to HTTP 0.9, i.e. don't send a status line.
266 default_request_version = http.HTTP_0_9
268 responses = BaseHTTPServer.BaseHTTPRequestHandler.responses
270 # Timeouts in seconds for socket layer
275 def __init__(self, server, handler, sock, client_addr):
276 """Initializes this class.
280 self.handler = handler
282 self.client_addr = client_addr
284 self.request_msg = http.HttpMessage()
285 self.response_msg = http.HttpMessage()
287 self.response_msg.start_line = \
288 http.HttpServerToClientStartLine(version=self.default_request_version,
289 code=None, reason=None)
291 # Disable Python's timeout
292 self.sock.settimeout(None)
294 # Operate in non-blocking mode
295 self.sock.setblocking(0)
297 logging.debug("Connection from %s:%s", client_addr[0], client_addr[1])
299 request_msg_reader = None
302 # Do the secret SSL handshake
303 if self.server.using_ssl:
304 self.sock.set_accept_state()
306 http.Handshake(self.sock, self.WRITE_TIMEOUT)
307 except http.HttpSessionHandshakeUnexpectedEOF:
313 request_msg_reader = self._ReadRequest()
315 # RFC2616, 14.23: All Internet-based HTTP/1.1 servers MUST respond
316 # with a 400 (Bad Request) status code to any HTTP/1.1 request
317 # message which lacks a Host header field.
318 if (self.request_msg.start_line.version == http.HTTP_1_1 and
319 http.HTTP_HOST not in self.request_msg.headers):
320 raise http.HttpBadRequest(message="Missing Host header")
322 (self.response_msg.start_line.code, self.response_msg.headers,
323 self.response_msg.body) = \
324 HandleServerRequest(self.handler, self.request_msg)
326 # Only wait for client to close if we didn't have any exception.
328 except http.HttpException, err:
329 self._SetErrorStatus(err)
331 # Try to send a response
334 http.ShutdownConnection(sock, self.CLOSE_TIMEOUT, self.WRITE_TIMEOUT,
335 request_msg_reader, force_close)
340 logging.debug("Disconnected %s:%s", client_addr[0], client_addr[1])
342 def _ReadRequest(self):
343 """Reads a request sent by client.
347 request_msg_reader = \
348 _HttpClientToServerMessageReader(self.sock, self.request_msg,
350 except http.HttpSocketTimeout:
351 raise http.HttpError("Timeout while reading request")
352 except socket.error, err:
353 raise http.HttpError("Error reading request: %s" % err)
355 self.response_msg.start_line.version = self.request_msg.start_line.version
357 return request_msg_reader
359 def _SendResponse(self):
360 """Sends the response to the client.
363 # HttpMessage.start_line can be of different types, pylint: disable=E1103
364 if self.response_msg.start_line.code is None:
367 if not self.response_msg.headers:
368 self.response_msg.headers = {}
370 self.response_msg.headers.update({
371 # TODO: Keep-alive is not supported
372 http.HTTP_CONNECTION: "close",
373 http.HTTP_DATE: _DateTimeHeader(),
374 http.HTTP_SERVER: http.HTTP_GANETI_VERSION,
377 # Get response reason based on code
378 response_code = self.response_msg.start_line.code
379 if response_code in self.responses:
380 response_reason = self.responses[response_code][0]
383 self.response_msg.start_line.reason = response_reason
385 logging.info("%s:%s %s %s", self.client_addr[0], self.client_addr[1],
386 self.request_msg.start_line, response_code)
389 _HttpServerToClientMessageWriter(self.sock, self.request_msg,
390 self.response_msg, self.WRITE_TIMEOUT)
391 except http.HttpSocketTimeout:
392 raise http.HttpError("Timeout while sending response")
393 except socket.error, err:
394 raise http.HttpError("Error sending response: %s" % err)
396 def _SetErrorStatus(self, err):
397 """Sets the response code and body from a HttpException.
399 @type err: HttpException
400 @param err: Exception instance
404 (shortmsg, longmsg) = self.responses[err.code]
406 shortmsg = longmsg = "Unknown"
409 message = err.message
415 "message": cgi.escape(message),
419 (content_type, body) = self.handler.FormatErrorMessage(values)
422 http.HTTP_CONTENT_TYPE: content_type,
426 headers.update(err.headers)
428 self.response_msg.start_line.code = err.code
429 self.response_msg.headers = headers
430 self.response_msg.body = body
433 class HttpServer(http.HttpBase, asyncore.dispatcher):
434 """Generic HTTP server class
439 def __init__(self, mainloop, local_address, port, handler,
440 ssl_params=None, ssl_verify_peer=False,
441 request_executor_class=None):
442 """Initializes the HTTP server
444 @type mainloop: ganeti.daemon.Mainloop
445 @param mainloop: Mainloop used to poll for I/O events
446 @type local_address: string
447 @param local_address: Local IP address to bind to
449 @param port: TCP port to listen on
450 @type ssl_params: HttpSslParams
451 @param ssl_params: SSL key and certificate
452 @type ssl_verify_peer: bool
453 @param ssl_verify_peer: Whether to require client certificate
454 and compare it with our certificate
455 @type request_executor_class: class
456 @param request_executor_class: an class derived from the
457 HttpServerRequestExecutor class
460 http.HttpBase.__init__(self)
461 asyncore.dispatcher.__init__(self)
463 if request_executor_class is None:
464 self.request_executor = HttpServerRequestExecutor
466 self.request_executor = request_executor_class
468 self.mainloop = mainloop
469 self.local_address = local_address
471 self.handler = handler
472 family = netutils.IPAddress.GetAddressFamily(local_address)
473 self.socket = self._CreateSocket(ssl_params, ssl_verify_peer, family)
475 # Allow port to be reused
476 self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
479 self.set_socket(self.socket)
480 self.accepting = True
481 mainloop.RegisterSignal(self)
484 self.socket.bind((self.local_address, self.port))
485 self.socket.listen(1024)
490 def handle_accept(self):
491 self._IncomingConnection()
493 def OnSignal(self, signum):
494 if signum == signal.SIGCHLD:
495 self._CollectChildren(True)
497 def _CollectChildren(self, quick):
498 """Checks whether any child processes are done
501 @param quick: Whether to only use non-blocking functions
505 # Don't wait for other processes if it should be a quick check
506 while len(self._children) > self.MAX_CHILDREN:
508 # Waiting without a timeout brings us into a potential DoS situation.
509 # As soon as too many children run, we'll not respond to new
510 # requests. The real solution would be to add a timeout for children
511 # and killing them after some time.
512 pid, _ = os.waitpid(0, 0)
515 if pid and pid in self._children:
516 self._children.remove(pid)
518 for child in self._children:
520 pid, _ = os.waitpid(child, os.WNOHANG)
523 if pid and pid in self._children:
524 self._children.remove(pid)
526 def _IncomingConnection(self):
527 """Called for each incoming connection
530 # pylint: disable=W0212
531 (connection, client_addr) = self.socket.accept()
533 self._CollectChildren(False)
539 # The client shouldn't keep the listening socket open. If the parent
540 # process is restarted, it would fail when there's already something
541 # listening (in this case its own child from a previous run) on the
549 # In case the handler code uses temporary files
550 utils.ResetTempfileModule()
552 self.request_executor(self, self.handler, connection, client_addr)
553 except Exception: # pylint: disable=W0703
554 logging.exception("Error while handling request from %s:%s",
555 client_addr[0], client_addr[1])
559 self._children.append(pid)
562 class HttpServerHandler(object):
563 """Base class for handling HTTP server requests.
565 Users of this class must subclass it and override the L{HandleRequest}
569 def PreHandleRequest(self, req):
570 """Called before handling a request.
572 Can be overridden by a subclass.
576 def HandleRequest(self, req):
577 """Handles a request.
579 Must be overridden by subclass.
582 raise NotImplementedError()
585 def FormatErrorMessage(values):
586 """Formats the body of an error message.
589 @param values: dictionary with keys C{code}, C{message} and C{explain}.
590 @rtype: tuple; (string, string)
591 @return: Content-type and response body
594 return (DEFAULT_ERROR_CONTENT_TYPE, DEFAULT_ERROR_MESSAGE % values)