Increase maximum HTTP message size
[ganeti-local] / lib / http / server.py
index 52b1340..b6f0504 100644 (file)
@@ -1,7 +1,7 @@
 #
 #
 
-# Copyright (C) 2007, 2008, 2010 Google Inc.
+# Copyright (C) 2007, 2008, 2010, 2012 Google Inc.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -34,6 +34,8 @@ import asyncore
 from ganeti import http
 from ganeti import utils
 from ganeti import netutils
+from ganeti import compat
+from ganeti import errors
 
 
 WEEKDAYNAME = ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"]
@@ -157,7 +159,7 @@ class _HttpClientToServerMessageReader(http.HttpMessageReader):
 
   """
   # Length limits
-  START_LINE_LENGTH_MAX = 4096
+  START_LINE_LENGTH_MAX = 8192
   HEADER_LENGTH_MAX = 4096
 
   def ParseStartLine(self, start_line):
@@ -200,7 +202,7 @@ class _HttpClientToServerMessageReader(http.HttpMessageReader):
 
       if version_number >= (2, 0):
         raise http.HttpVersionNotSupported("Invalid HTTP Version (%s)" %
-                                      base_version_number)
+                                           base_version_number)
 
     elif len(words) == 2:
       version = http.HTTP_0_9
@@ -214,161 +216,144 @@ class _HttpClientToServerMessageReader(http.HttpMessageReader):
     return http.HttpClientToServerStartLine(method, path, version)
 
 
-class HttpServerRequestExecutor(object):
-  """Implements server side of HTTP.
-
-  This class implements the server side of HTTP. It's based on code of
-  Python's BaseHTTPServer, from both version 2.4 and 3k. It does not
-  support non-ASCII character encodings. Keep-alive connections are
-  not supported.
+def _HandleServerRequestInner(handler, req_msg):
+  """Calls the handler function for the current request.
 
   """
+  handler_context = _HttpServerRequest(req_msg.start_line.method,
+                                       req_msg.start_line.path,
+                                       req_msg.headers,
+                                       req_msg.body)
+
+  logging.debug("Handling request %r", handler_context)
+
+  try:
+    try:
+      # Authentication, etc.
+      handler.PreHandleRequest(handler_context)
+
+      # Call actual request handler
+      result = handler.HandleRequest(handler_context)
+    except (http.HttpException, errors.RapiTestResult,
+            KeyboardInterrupt, SystemExit):
+      raise
+    except Exception, err:
+      logging.exception("Caught exception")
+      raise http.HttpInternalServerError(message=str(err))
+    except:
+      logging.exception("Unknown exception")
+      raise http.HttpInternalServerError(message="Unknown error")
+
+    if not isinstance(result, basestring):
+      raise http.HttpError("Handler function didn't return string type")
+
+    return (http.HTTP_OK, handler_context.resp_headers, result)
+  finally:
+    # No reason to keep this any longer, even for exceptions
+    handler_context.private = None
+
+
+class HttpResponder(object):
   # The default request version.  This only affects responses up until
   # the point where the request line is parsed, so it mainly decides what
   # the client gets back when sending a malformed request line.
   # Most web servers default to HTTP 0.9, i.e. don't send a status line.
   default_request_version = http.HTTP_0_9
 
-  # Error message settings
-  error_message_format = DEFAULT_ERROR_MESSAGE
-  error_content_type = DEFAULT_ERROR_CONTENT_TYPE
-
   responses = BaseHTTPServer.BaseHTTPRequestHandler.responses
 
-  # Timeouts in seconds for socket layer
-  WRITE_TIMEOUT = 10
-  READ_TIMEOUT = 10
-  CLOSE_TIMEOUT = 1
-
-  def __init__(self, server, sock, client_addr):
+  def __init__(self, handler):
     """Initializes this class.
 
     """
-    self.server = server
-    self.sock = sock
-    self.client_addr = client_addr
+    self._handler = handler
+
+  def __call__(self, fn):
+    """Handles a request.
 
-    self.request_msg = http.HttpMessage()
-    self.response_msg = http.HttpMessage()
+    @type fn: callable
+    @param fn: Callback for retrieving HTTP request, must return a tuple
+      containing request message (L{http.HttpMessage}) and C{None} or the
+      message reader (L{_HttpClientToServerMessageReader})
 
-    self.response_msg.start_line = \
+    """
+    response_msg = http.HttpMessage()
+    response_msg.start_line = \
       http.HttpServerToClientStartLine(version=self.default_request_version,
                                        code=None, reason=None)
 
-    # Disable Python's timeout
-    self.sock.settimeout(None)
-
-    # Operate in non-blocking mode
-    self.sock.setblocking(0)
+    force_close = True
 
-    logging.debug("Connection from %s:%s", client_addr[0], client_addr[1])
     try:
-      request_msg_reader = None
-      force_close = True
-      try:
-        # Do the secret SSL handshake
-        if self.server.using_ssl:
-          self.sock.set_accept_state()
-          try:
-            http.Handshake(self.sock, self.WRITE_TIMEOUT)
-          except http.HttpSessionHandshakeUnexpectedEOF:
-            # Ignore rest
-            return
+      (request_msg, req_msg_reader) = fn()
+
+      response_msg.start_line.version = request_msg.start_line.version
+
+      # RFC2616, 14.23: All Internet-based HTTP/1.1 servers MUST respond
+      # with a 400 (Bad Request) status code to any HTTP/1.1 request
+      # message which lacks a Host header field.
+      if (request_msg.start_line.version == http.HTTP_1_1 and
+          not (request_msg.headers and
+               http.HTTP_HOST in request_msg.headers)):
+        raise http.HttpBadRequest(message="Missing Host header")
+
+      (response_msg.start_line.code, response_msg.headers,
+       response_msg.body) = \
+        _HandleServerRequestInner(self._handler, request_msg)
+    except http.HttpException, err:
+      self._SetError(self.responses, self._handler, response_msg, err)
+    else:
+      # Only wait for client to close if we didn't have any exception.
+      force_close = False
 
-        try:
-          try:
-            request_msg_reader = self._ReadRequest()
-
-            # RFC2616, 14.23: All Internet-based HTTP/1.1 servers MUST respond
-            # with a 400 (Bad Request) status code to any HTTP/1.1 request
-            # message which lacks a Host header field.
-            if (self.request_msg.start_line.version == http.HTTP_1_1 and
-                http.HTTP_HOST not in self.request_msg.headers):
-              raise http.HttpBadRequest(message="Missing Host header")
-
-            self._HandleRequest()
-
-            # Only wait for client to close if we didn't have any exception.
-            force_close = False
-          except http.HttpException, err:
-            self._SetErrorStatus(err)
-        finally:
-          # Try to send a response
-          self._SendResponse()
-      finally:
-        http.ShutdownConnection(sock, self.CLOSE_TIMEOUT, self.WRITE_TIMEOUT,
-                                request_msg_reader, force_close)
+    return (request_msg, req_msg_reader, force_close,
+            self._Finalize(self.responses, response_msg))
 
-      self.sock.close()
-      self.sock = None
-    finally:
-      logging.debug("Disconnected %s:%s", client_addr[0], client_addr[1])
+  @staticmethod
+  def _SetError(responses, handler, response_msg, err):
+    """Sets the response code and body from a HttpException.
 
-  def _ReadRequest(self):
-    """Reads a request sent by client.
+    @type err: HttpException
+    @param err: Exception instance
 
     """
     try:
-      request_msg_reader = \
-        _HttpClientToServerMessageReader(self.sock, self.request_msg,
-                                         self.READ_TIMEOUT)
-    except http.HttpSocketTimeout:
-      raise http.HttpError("Timeout while reading request")
-    except socket.error, err:
-      raise http.HttpError("Error reading request: %s" % err)
-
-    self.response_msg.start_line.version = self.request_msg.start_line.version
+      (shortmsg, longmsg) = responses[err.code]
+    except KeyError:
+      shortmsg = longmsg = "Unknown"
 
-    return request_msg_reader
+    if err.message:
+      message = err.message
+    else:
+      message = shortmsg
 
-  def _HandleRequest(self):
-    """Calls the handler function for the current request.
+    values = {
+      "code": err.code,
+      "message": cgi.escape(message),
+      "explain": longmsg,
+      }
 
-    """
-    handler_context = _HttpServerRequest(self.request_msg.start_line.method,
-                                         self.request_msg.start_line.path,
-                                         self.request_msg.headers,
-                                         self.request_msg.body)
+    (content_type, body) = handler.FormatErrorMessage(values)
 
-    logging.debug("Handling request %r", handler_context)
+    headers = {
+      http.HTTP_CONTENT_TYPE: content_type,
+      }
 
-    try:
-      try:
-        # Authentication, etc.
-        self.server.PreHandleRequest(handler_context)
-
-        # Call actual request handler
-        result = self.server.HandleRequest(handler_context)
-      except (http.HttpException, KeyboardInterrupt, SystemExit):
-        raise
-      except Exception, err:
-        logging.exception("Caught exception")
-        raise http.HttpInternalServerError(message=str(err))
-      except:
-        logging.exception("Unknown exception")
-        raise http.HttpInternalServerError(message="Unknown error")
-
-      if not isinstance(result, basestring):
-        raise http.HttpError("Handler function didn't return string type")
-
-      self.response_msg.start_line.code = http.HTTP_OK
-      self.response_msg.headers = handler_context.resp_headers
-      self.response_msg.body = result
-    finally:
-      # No reason to keep this any longer, even for exceptions
-      handler_context.private = None
+    if err.headers:
+      headers.update(err.headers)
 
-  def _SendResponse(self):
-    """Sends the response to the client.
+    response_msg.start_line.code = err.code
+    response_msg.headers = headers
+    response_msg.body = body
 
-    """
-    if self.response_msg.start_line.code is None:
-      return
+  @staticmethod
+  def _Finalize(responses, msg):
+    assert msg.start_line.reason is None
 
-    if not self.response_msg.headers:
-      self.response_msg.headers = {}
+    if not msg.headers:
+      msg.headers = {}
 
-    self.response_msg.headers.update({
+    msg.headers.update({
       # TODO: Keep-alive is not supported
       http.HTTP_CONNECTION: "close",
       http.HTTP_DATE: _DateTimeHeader(),
@@ -376,78 +361,114 @@ class HttpServerRequestExecutor(object):
       })
 
     # Get response reason based on code
-    response_code = self.response_msg.start_line.code
-    if response_code in self.responses:
-      response_reason = self.responses[response_code][0]
+    try:
+      code_desc = responses[msg.start_line.code]
+    except KeyError:
+      reason = ""
     else:
-      response_reason = ""
-    self.response_msg.start_line.reason = response_reason
+      (reason, _) = code_desc
 
-    logging.info("%s:%s %s %s", self.client_addr[0], self.client_addr[1],
-                 self.request_msg.start_line, response_code)
+    msg.start_line.reason = reason
 
-    try:
-      _HttpServerToClientMessageWriter(self.sock, self.request_msg,
-                                       self.response_msg, self.WRITE_TIMEOUT)
-    except http.HttpSocketTimeout:
-      raise http.HttpError("Timeout while sending response")
-    except socket.error, err:
-      raise http.HttpError("Error sending response: %s" % err)
+    return msg
 
-  def _SetErrorStatus(self, err):
-    """Sets the response code and body from a HttpException.
 
-    @type err: HttpException
-    @param err: Exception instance
+class HttpServerRequestExecutor(object):
+  """Implements server side of HTTP.
+
+  This class implements the server side of HTTP. It's based on code of
+  Python's BaseHTTPServer, from both version 2.4 and 3k. It does not
+  support non-ASCII character encodings. Keep-alive connections are
+  not supported.
+
+  """
+  # Timeouts in seconds for socket layer
+  WRITE_TIMEOUT = 10
+  READ_TIMEOUT = 10
+  CLOSE_TIMEOUT = 1
+
+  def __init__(self, server, handler, sock, client_addr):
+    """Initializes this class.
 
     """
+    responder = HttpResponder(handler)
+
+    # Disable Python's timeout
+    sock.settimeout(None)
+
+    # Operate in non-blocking mode
+    sock.setblocking(0)
+
+    request_msg_reader = None
+    force_close = True
+
+    logging.debug("Connection from %s:%s", client_addr[0], client_addr[1])
     try:
-      (shortmsg, longmsg) = self.responses[err.code]
-    except KeyError:
-      shortmsg = longmsg = "Unknown"
+      # Block for closing connection
+      try:
+        # Do the secret SSL handshake
+        if server.using_ssl:
+          sock.set_accept_state()
+          try:
+            http.Handshake(sock, self.WRITE_TIMEOUT)
+          except http.HttpSessionHandshakeUnexpectedEOF:
+            # Ignore rest
+            return
 
-    if err.message:
-      message = err.message
-    else:
-      message = shortmsg
+        (request_msg, request_msg_reader, force_close, response_msg) = \
+          responder(compat.partial(self._ReadRequest, sock, self.READ_TIMEOUT))
+        if response_msg:
+          # HttpMessage.start_line can be of different types
+          # Instance of 'HttpClientToServerStartLine' has no 'code' member
+          # pylint: disable=E1103,E1101
+          logging.info("%s:%s %s %s", client_addr[0], client_addr[1],
+                       request_msg.start_line, response_msg.start_line.code)
+          self._SendResponse(sock, request_msg, response_msg,
+                             self.WRITE_TIMEOUT)
+      finally:
+        http.ShutdownConnection(sock, self.CLOSE_TIMEOUT, self.WRITE_TIMEOUT,
+                                request_msg_reader, force_close)
 
-    values = {
-      "code": err.code,
-      "message": cgi.escape(message),
-      "explain": longmsg,
-      }
+      sock.close()
+    finally:
+      logging.debug("Disconnected %s:%s", client_addr[0], client_addr[1])
 
-    self.response_msg.start_line.code = err.code
+  @staticmethod
+  def _ReadRequest(sock, timeout):
+    """Reads a request sent by client.
 
-    headers = {}
-    if err.headers:
-      headers.update(err.headers)
-    headers[http.HTTP_CONTENT_TYPE] = self.error_content_type
-    self.response_msg.headers = headers
+    """
+    msg = http.HttpMessage()
 
-    self.response_msg.body = self._FormatErrorMessage(values)
+    try:
+      reader = _HttpClientToServerMessageReader(sock, msg, timeout)
+    except http.HttpSocketTimeout:
+      raise http.HttpError("Timeout while reading request")
+    except socket.error, err:
+      raise http.HttpError("Error reading request: %s" % err)
 
-  def _FormatErrorMessage(self, values):
-    """Formats the body of an error message.
+    return (msg, reader)
 
-    @type values: dict
-    @param values: dictionary with keys code, message and explain.
-    @rtype: string
-    @return: the body of the message
+  @staticmethod
+  def _SendResponse(sock, req_msg, msg, timeout):
+    """Sends the response to the client.
 
     """
-    return self.error_message_format % values
+    try:
+      _HttpServerToClientMessageWriter(sock, req_msg, msg, timeout)
+    except http.HttpSocketTimeout:
+      raise http.HttpError("Timeout while sending response")
+    except socket.error, err:
+      raise http.HttpError("Error sending response: %s" % err)
 
 
 class HttpServer(http.HttpBase, asyncore.dispatcher):
   """Generic HTTP server class
 
-  Users of this class must subclass it and override the HandleRequest function.
-
   """
   MAX_CHILDREN = 20
 
-  def __init__(self, mainloop, local_address, port,
+  def __init__(self, mainloop, local_address, port, handler,
                ssl_params=None, ssl_verify_peer=False,
                request_executor_class=None):
     """Initializes the HTTP server
@@ -479,6 +500,7 @@ class HttpServer(http.HttpBase, asyncore.dispatcher):
     self.mainloop = mainloop
     self.local_address = local_address
     self.port = port
+    self.handler = handler
     family = netutils.IPAddress.GetAddressFamily(local_address)
     self.socket = self._CreateSocket(ssl_params, ssl_verify_peer, family)
 
@@ -537,7 +559,7 @@ class HttpServer(http.HttpBase, asyncore.dispatcher):
     """Called for each incoming connection
 
     """
-    # pylint: disable-msg=W0212
+    # pylint: disable=W0212
     (connection, client_addr) = self.socket.accept()
 
     self._CollectChildren(False)
@@ -559,8 +581,8 @@ class HttpServer(http.HttpBase, asyncore.dispatcher):
         # In case the handler code uses temporary files
         utils.ResetTempfileModule()
 
-        self.request_executor(self, connection, client_addr)
-      except Exception: # pylint: disable-msg=W0703
+        self.request_executor(self, self.handler, connection, client_addr)
+      except Exception: # pylint: disable=W0703
         logging.exception("Error while handling request from %s:%s",
                           client_addr[0], client_addr[1])
         os._exit(1)
@@ -568,6 +590,14 @@ class HttpServer(http.HttpBase, asyncore.dispatcher):
     else:
       self._children.append(pid)
 
+
+class HttpServerHandler(object):
+  """Base class for handling HTTP server requests.
+
+  Users of this class must subclass it and override the L{HandleRequest}
+  function.
+
+  """
   def PreHandleRequest(self, req):
     """Called before handling a request.
 
@@ -582,3 +612,15 @@ class HttpServer(http.HttpBase, asyncore.dispatcher):
 
     """
     raise NotImplementedError()
+
+  @staticmethod
+  def FormatErrorMessage(values):
+    """Formats the body of an error message.
+
+    @type values: dict
+    @param values: dictionary with keys C{code}, C{message} and C{explain}.
+    @rtype: tuple; (string, string)
+    @return: Content-type and response body
+
+    """
+    return (DEFAULT_ERROR_CONTENT_TYPE, DEFAULT_ERROR_MESSAGE % values)