Synnefo » snf-ganeti

#!/usr/bin/python

#

# Copyright (C) 2006, 2007 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

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful, but

# WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

# General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

# 02110-1301, USA.

"""Ganeti Remote API master script.

"""

# pylint: disable-msg=C0103,W0142

# C0103: Invalid name ganeti-watcher

import logging

import optparse

import sys

import os

import os.path

from ganeti import constants

from ganeti import http

from ganeti import daemon

from ganeti import ssconf

from ganeti import luxi

from ganeti import serializer

from ganeti.rapi import connector

import ganeti.http.auth   # pylint: disable-msg=W0611

import ganeti.http.server

class RemoteApiRequestContext(object):

  """Data structure for Remote API requests.

  """

  def __init__(self):

    self.handler = None

    self.handler_fn = None

    self.handler_access = None

class JsonErrorRequestExecutor(http.server.HttpServerRequestExecutor):

  """Custom Request Executor class that formats HTTP errors in JSON.

  """

  error_content_type = "application/json"

  def _FormatErrorMessage(self, values):

    """Formats the body of an error message.

    @type values: dict

    @param values: dictionary with keys code, message and explain.

    @rtype: string

    @return: the body of the message

    """

    return serializer.DumpJson(values, indent=True)

class RemoteApiHttpServer(http.auth.HttpServerRequestAuthentication,

                          http.server.HttpServer):

  """REST Request Handler Class.

  """

  AUTH_REALM = "Ganeti Remote API"

  def __init__(self, *args, **kwargs):

    http.server.HttpServer.__init__(self, *args, **kwargs)

    http.auth.HttpServerRequestAuthentication.__init__(self)

    self._resmap = connector.Mapper()

    # Load password file

    if os.path.isfile(constants.RAPI_USERS_FILE):

      self._users = http.auth.ReadPasswordFile(constants.RAPI_USERS_FILE)

    else:

      self._users = None

  def _GetRequestContext(self, req):

    """Returns the context for a request.

    The context is cached in the req.private variable.

    """

    if req.private is None:

      (HandlerClass, items, args) = \

                     self._resmap.getController(req.request_path)

      ctx = RemoteApiRequestContext()

      ctx.handler = HandlerClass(items, args, req)

      method = req.request_method.upper()

      try:

        ctx.handler_fn = getattr(ctx.handler, method)

      except AttributeError:

        raise http.HttpBadRequest("Method %s is unsupported for path %s" %

                                  (method, req.request_path))

      ctx.handler_access = getattr(ctx.handler, "%s_ACCESS" % method, None)

      # Require permissions definition (usually in the base class)

      if ctx.handler_access is None:

        raise AssertionError("Permissions definition missing")

      req.private = ctx

    # Check for expected attributes

    assert req.private.handler

    assert req.private.handler_fn

    assert req.private.handler_access is not None

    return req.private

  def AuthenticationRequired(self, req):

    """Determine whether authentication is required.

    """

    return bool(self._GetRequestContext(req).handler_access)

  def Authenticate(self, req, username, password):

    """Checks whether a user can access a resource.

    """

    ctx = self._GetRequestContext(req)

    # Check username and password

    valid_user = False

    if self._users:

      user = self._users.get(username, None)

      if user and self.VerifyBasicAuthPassword(req, username, password,

                                               user.password):

        valid_user = True

    if not valid_user:

      # Unknown user or password wrong

      return False

    if (not ctx.handler_access or

        set(user.options).intersection(ctx.handler_access)):

      # Allow access

      return True

    # Access forbidden

    raise http.HttpForbidden()

  def HandleRequest(self, req):

    """Handles a request.

    """

    ctx = self._GetRequestContext(req)

    try:

      result = ctx.handler_fn()

      sn = ctx.handler.getSerialNumber()

      if sn:

        req.response_headers[http.HTTP_ETAG] = str(sn)

    except luxi.TimeoutError:

      raise http.HttpGatewayTimeout()

    except luxi.ProtocolError, err:

      raise http.HttpBadGateway(str(err))

    except:

      method = req.request_method.upper()

      logging.exception("Error while handling the %s request", method)

      raise

    return result

def CheckRapi(options, args):

  """Initial checks whether to run or exit with a failure.

  """

  if args: # rapi doesn't take any arguments

    print >> sys.stderr, ("Usage: %s [-f] [-d] [-p port] [-b ADDRESS]" %

                          sys.argv[0])

    sys.exit(constants.EXIT_FAILURE)

  ssconf.CheckMaster(options.debug)

def ExecRapi(options, _):

  """Main remote API function, executed with the PID file held.

  """

  # Read SSL certificate

  if options.ssl:

    ssl_params = http.HttpSslParams(ssl_key_path=options.ssl_key,

                                    ssl_cert_path=options.ssl_cert)

  else:

    ssl_params = None

  mainloop = daemon.Mainloop()

  server = RemoteApiHttpServer(mainloop, options.bind_address, options.port,

                               ssl_params=ssl_params, ssl_verify_peer=False,

                               request_executor_class=JsonErrorRequestExecutor)

  server.Start()

  try:

    mainloop.Run()

  finally:

    server.Stop()

def main():

  """Main function.

  """

  parser = optparse.OptionParser(description="Ganeti Remote API",

                    usage="%prog [-f] [-d] [-p port] [-b ADDRESS]",

                    version="%%prog (ganeti) %s" % constants.RAPI_VERSION)

  dirs = [(val, constants.RUN_DIRS_MODE) for val in constants.SUB_RUN_DIRS]

  dirs.append((constants.LOG_OS_DIR, 0750))

  daemon.GenericMain(constants.RAPI, parser, dirs, CheckRapi, ExecRapi)

if __name__ == "__main__":

  main()