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gns3-server/gns3server/modules/base.py

324 lines
10 KiB
Python

# -*- coding: utf-8 -*-
#
# Copyright (C) 2013 GNS3 Technologies 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 3 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, see <http://www.gnu.org/licenses/>.
"""
Base class (interface) for modules
"""
import sys
import traceback
import gns3server.jsonrpc as jsonrpc
import multiprocessing
import zmq
import signal
from jsonschema import validate, ValidationError
import logging
log = logging.getLogger(__name__)
class IModule(multiprocessing.Process):
"""
Module interface.
:param name: module name
:param args: arguments for the module
:param kwargs: named arguments for the module
"""
modules = {}
def __init__(self, name, *args, **kwargs):
multiprocessing.Process.__init__(self, name=name)
self._context = None
self._ioloop = None
self._stream = None
self._dealer = None
self._zmq_host = args[0] # ZeroMQ server address
self._zmq_port = args[1] # ZeroMQ server port
self._current_session = None
self._current_destination = None
self._current_call_id = None
self._stopping = False
def _setup(self):
"""
Sets up PyZMQ and creates the stream to handle requests
"""
self._context = zmq.Context()
self._ioloop = zmq.eventloop.ioloop.IOLoop.instance()
self._stream = self._create_stream(self._zmq_host, self._zmq_port, self._decode_request)
def _create_stream(self, host=None, port=0, callback=None):
"""
Creates a new ZMQ stream.
:returns: ZMQ stream instance
"""
self._dealer = self._context.socket(zmq.DEALER)
self._dealer.setsockopt(zmq.IDENTITY, self.name.encode("utf-8"))
if host and port:
log.info("ZeroMQ client ({}) connecting to {}:{}".format(self.name, host, port))
try:
self._dealer.connect("tcp://{}:{}".format(host, port))
except zmq.error.ZMQError as e:
log.critical("Could not connect to ZeroMQ server on {}:{}, reason: {}".format(host, port, e))
raise SystemExit
else:
log.info("ZeroMQ client ({}) connecting to ipc:///tmp/gns3.ipc".format(self.name))
try:
self._dealer.connect("ipc:///tmp/gns3.ipc")
except zmq.error.ZMQError as e:
log.critical("Could not connect to ZeroMQ server on ipc:///tmp/gns3.ipc, reason: {}".format(e))
raise SystemExit
stream = zmq.eventloop.zmqstream.ZMQStream(self._dealer, self._ioloop)
if callback:
stream.on_recv(callback)
return stream
def add_periodic_callback(self, callback, time):
"""
Adds a periodic callback to the ioloop.
:param callback: callback to be called
:param time: frequency when the callback is executed
"""
periodic_callback = zmq.eventloop.ioloop.PeriodicCallback(callback, time, self._ioloop)
return periodic_callback
def run(self):
"""
Starts the event loop
"""
def signal_handler(signum=None, frame=None):
log.warning("Module {} got signal {}, exiting...".format(self.name, signum))
self.stop(signum)
signals = [signal.SIGTERM, signal.SIGINT]
if not sys.platform.startswith("win"):
signals.extend([signal.SIGHUP, signal.SIGQUIT])
else:
signals.extend([signal.SIGBREAK])
for sig in signals:
signal.signal(sig, signal_handler)
log.info("{} module running with PID {}".format(self.name, self.pid))
self._setup()
try:
self._ioloop.start()
except KeyboardInterrupt:
return
log.info("{} module has stopped".format(self.name))
def _shutdown(self):
"""
Shutdowns the I/O loop and the ZeroMQ stream & socket
"""
self._ioloop.stop()
if self._stream and not self._stream.closed:
# close the zeroMQ stream
self._stream.close()
if self._dealer and not self._dealer.closed:
# close the ZeroMQ dealer socket
self._dealer.close()
def stop(self, signum=None):
"""
Adds a callback to stop the event loop & ZeroMQ.
:param signum: signal number (if called by the signal handler)
"""
if not self._stopping:
self._stopping = True
if signum:
self._ioloop.add_callback_from_signal(self._shutdown)
else:
self._shutdown()
def send_response(self, results):
"""
Sends a response back to the requester.
:param results: JSON results to the ZeroMQ server
"""
jsonrpc_response = jsonrpc.JSONRPCResponse(results, self._current_call_id)()
# add session to the response
response = [self._current_session, jsonrpc_response]
log.debug("ZeroMQ client ({}) sending: {}".format(self.name, response))
self._stream.send_json(response)
def send_param_error(self):
"""
Sends a param error back to the requester.
"""
jsonrpc_response = jsonrpc.JSONRPCInvalidParams(self._current_call_id)()
# add session to the response
response = [self._current_session, jsonrpc_response]
log.info("ZeroMQ client ({}) sending JSON-RPC param error for call id {}".format(self.name, self._current_call_id))
self._stream.send_json(response)
def send_internal_error(self):
"""
Sends a param error back to the requester.
"""
jsonrpc_response = jsonrpc.JSONRPCInternalError()()
# add session to the response
response = [self._current_session, jsonrpc_response]
log.critical("ZeroMQ client ({}) sending JSON-RPC internal error".format(self.name))
self._stream.send_json(response)
def send_custom_error(self, message, code=-3200):
"""
Sends a custom error back to the requester.
"""
jsonrpc_response = jsonrpc.JSONRPCCustomError(code, message, self._current_call_id)()
# add session to the response
response = [self._current_session, jsonrpc_response]
log.info("ZeroMQ client ({}) sending JSON-RPC custom error: {} for call id {}".format(self.name,
message,
self._current_call_id))
self._stream.send_json(response)
def send_notification(self, destination, results):
"""
Sends a notification
:param destination: destination (or method)
:param results: JSON results to the ZeroMQ router
"""
jsonrpc_response = jsonrpc.JSONRPCNotification(destination, results)()
# add session to the response
response = [self._current_session, jsonrpc_response]
log.debug("ZeroMQ client ({}) sending: {}".format(self.name, response))
self._stream.send_json(response)
def _decode_request(self, request):
"""
Decodes the request to JSON.
:param request: request from ZeroMQ server
"""
# server is shutting down, do not process
# more request
if self._stopping:
return
try:
request = zmq.utils.jsonapi.loads(request[0])
except ValueError:
self._current_session = None
self.send_internal_error()
return
log.debug("ZeroMQ client ({}) received: {}".format(self.name, request))
self._current_session = request[0]
self._current_call_id = request[1].get("id")
destination = request[1].get("method")
params = request[1].get("params")
if destination not in self.modules[self.name]:
self.send_internal_error()
return
log.debug("Routing request to {}: {}".format(destination, request[1]))
try:
self.modules[self.name][destination](self, params)
except Exception as e:
log.error("uncaught exception {type}".format(type=type(e)), exc_info=1)
exc_type, exc_value, exc_tb = sys.exc_info()
lines = traceback.format_exception(exc_type, exc_value, exc_tb)
tb = "\n" . join(lines)
self.send_custom_error("uncaught exception {type}: {string}\n{tb}".format(type=type(e),
string=str(e),
tb=tb))
def validate_request(self, request, schema):
"""
Validates a request.
:param request: request (JSON-RPC params)
:param schema: JSON-SCHEMA to validate the request
:returns: True or False
"""
# check if we have a request
if request == None:
self.send_param_error()
return False
log.debug("received request {}".format(request))
# validate the request
try:
validate(request, schema)
except ValidationError as e:
self.send_custom_error("request validation error: {}".format(e))
return False
return True
def destinations(self):
"""
Destinations handled by this module.
:returns: list of destinations
"""
if not self.name in self.modules:
log.warn("no destinations found for module {}".format(self.name))
return []
return self.modules[self.name].keys()
@classmethod
def route(cls, destination):
"""
Decorator to register a destination routed to a method
:param destination: destination to be routed
"""
def wrapper(method):
module = destination.split(".")[0]
if not module in cls.modules:
cls.modules[module] = {}
cls.modules[module][destination] = method
return method
return wrapper