Merge branch 'fsm_as_eventhandler'

.drone.yml

@@ -10,4 +10,4 @@ pipeline:
       - docker push eu.gcr.io/avatao-challengestore/tutorial-framework:${DRONE_TAG}
     when:
       event: 'tag'
-      branch: refs/tags/bombay-20*
+      branch: refs/tags/mainecoon-20*

Dockerfile

@@ -37,6 +37,7 @@ ENV PYTHONPATH="/usr/local/lib"                                            \
     TFW_LIB_DIR="/usr/local/lib/"                                          \
     TFW_TERMINADO_DIR="/tmp/terminado_server"                              \
     TFW_FRONTEND_DIR="/srv/frontend"                                       \
+    TFW_SERVER_DIR="/srv/.tfw"                                             \
     TFW_HISTFILE="/home/${AVATAO_USER}/.bash_history"                      \
     PROMPT_COMMAND="history -a"
 
@@ -45,10 +46,12 @@ RUN echo "export HISTFILE=${TFW_HISTFILE}" >> /tmp/bashrc &&\
     cat /tmp/bashrc >> /home/${AVATAO_USER}/.bashrc
 
 COPY supervisor/supervisord.conf ${TFW_SUPERVISORD_CONF}
+COPY supervisor/components/ ${TFW_SUPERVISORD_COMPONENTS}
 COPY nginx/nginx.conf ${TFW_NGINX_CONF}
 COPY nginx/default.conf ${TFW_NGINX_DEFAULT}
 COPY nginx/components/ ${TFW_NGINX_COMPONENTS}
 COPY lib LICENSE ${TFW_LIB_DIR}
+COPY supervisor/tfw_server.py ${TFW_SERVER_DIR}/
 
 RUN for dir in "${TFW_LIB_DIR}"/{tfw,tao,envvars} "/etc/nginx" "/etc/supervisor"; do \
         chown -R root:root "$dir" && chmod -R 700 "$dir";                            \

README.md

@@ -20,6 +20,20 @@ Frontend components use websockets to connect to the TFW server, to which you ca
 
 ![TFW architecture](docs/tfw_architecture.png)
 
+### Networking details
+
+Event handlers connect to the TFW server using ZMQ.
+They receive messages on their `SUB`(scribe) sockets, which are connected to the `PUB`(lish) socket of the server.
+Event handlers reply on their `PUSH` socket, then their messages are received on the `PULL` socket of the server.
+
+The TFW server is basically just a fancy proxy.
+It's behaviour is quite simple: it proxies every message received from the fontend to the event handlers and vice versa.
+
+The server is also capable of "mirroring" messages back to their source.
+This is useful for communication between event handlers or frontend components (event handler to event handler or frontend component to frontend component communication).
+
+Components can also broadcast messages (broadcasted messages are received both by event handlers and the frontend as well).
+
 ### Event handlers
 
 Imagine event handlers as callbacks that are invoked when TFW receives a specific type of message. For instance, you could send a message to the framework when the user does something of note.
@@ -75,11 +89,180 @@ The TFW message format:
 - The `data` object can contain anything you might want to send
 - The `trigger` key is an optional field that triggers an FSM action with that name from the current state (whatever that might be)
 
+To mirror messages back to their sources you can use a special messaging format, in which the message to be mirrored is enveloped inside the `data` field of the outer message:
+
+```text
+    "key": "mirror",
+    "data":
+    {
+        ...
+        The message you want to mirror (with it's own "key" and "data" fields)
+        ...
+    }
+```
+
+Broadcasting messages is possible in a similar manner by using `"key": "broadcast"` in the outer message.
 
 ## Where to go next
 
 Most of the components you need have docstrings included (hang on tight, this is work in progress) – refer to them for usage info.
 
-In the `docs` folder you can find our Sphinx-based API documentation, which you can build using the `hack/tfw.sh` script in the [test-tutorial-framework](https://github.com/avatao-content/test-tutorial-framework) repository.
+In the `docs` folder you can find our Sphinx-based documentation, which you can build using the `hack/tfw.sh` script in the [test-tutorial-framework](https://github.com/avatao-content/test-tutorial-framework) repository.
 
 To get started you should take a look at [test-tutorial-framework](https://github.com/avatao-content/test-tutorial-framework), which serves as an example project as well.
+
+## API
+
+APIs exposed by our pre-witten event handlers are documented here.
+
+### IdeEventHandler
+
+You can read the content of the currently selected file like so:
+```
+{ 
+    "key": "ide",
+    "data":
+    {
+        "command": "read"
+    }
+}
+```
+
+Use the following message to overwrite the content of the currently selected file:
+```
+{ 
+    "key": "ide",
+    "data":
+    {
+        "command": "write",
+        "content": ...string...
+    }
+}
+```
+
+To select a file use the following message:
+```
+{ 
+    "key": "ide",
+    "data":
+    {
+        "command": "select",
+        "filename": ...string...
+    }
+}
+```
+
+You can switch to a new working directory using this message (note that the directory must be in `allowed_directories`):
+```
+{ 
+    "key": "ide",
+    "data":
+    {
+        "command": "selectdir",
+        "directory": ...string...
+    }
+}
+```
+
+Overwriting the current list of excluded file patterns is possible with this message:
+```
+{ 
+    "key": "ide",
+    "data":
+    {
+        "command": "exclude",
+        "exclude": ...array of strings...
+    }
+}
+```
+
+### TerminalEventHandler
+
+Writing to the terminal:
+```
+{ 
+    "key": "shell",
+    "data":
+    {
+        "command": "write",
+        "value": ...string...
+    }
+}
+```
+
+You can read terminal command history like so:
+```
+{ 
+    "key": "shell",
+    "data":
+    {
+        "command": "read",
+        "count": ...number...
+    }
+}
+```
+
+### ProcessManagingEventHandler
+
+Starting, stopping and restarting supervisor processes can be done using similar messages (where `command` is `start`, `stop` or `restart`):
+```
+{ 
+    "key": "processmanager",
+    "data":
+    {
+        "command": ...string...,
+        "process_name": ...string...
+    }
+}
+```
+
+### LogMonitoringEventHandler
+
+To change which supervisor process is monitored use this message:
+```
+{ 
+    "key": "logmonitor",
+    "data" :
+    {
+        "command": "process_name",
+        "value": ...string...
+    }
+}
+```
+
+To set the tail length of logs (the monitor will send back the last `value` characters of the log):
+```
+{ 
+    "key": "logmonitor",
+    "data" :
+    {
+        "command": "log_tail",
+        "value": ...number...
+    }
+}
+```
+
+### FSMManagingEventHandler
+
+To attempt executing a trigger on the FSM use:
+```
+{
+    "key": "fsm",
+    "data" :
+    {
+        "command": "trigger",
+        "value": ...string...
+    }
+}
+```
+
+To force the broadcasting of an FSM update you can use this message:
+```
+{
+    "key": "fsm",
+    "data" :
+    {
+        "command": "update"
+    }
+}
+```

VERSION

@@ -1 +1 @@
-bombay
+mainecoon

docs/source/conf.py

@@ -26,7 +26,7 @@ author = 'Kristóf Tóth'
 # The short X.Y version
 version = ''
 # The full version, including alpha/beta/rc tags
-release = 'bombay'
+release = 'mainecoon'
 
 
 # -- General configuration ---------------------------------------------------

lib/tfw/__init__.py

@@ -1,6 +1,7 @@
 # Copyright (C) 2018 Avatao.com Innovative Learning Kft.
 # All Rights Reserved. See LICENSE file for details.
 
-from .event_handler_base import EventHandlerBase, TriggeredEventHandler
+from .event_handler_base import EventHandlerBase, TriggeredEventHandler, BroadcastingEventHandler
 from .fsm_base import FSMBase
 from .linear_fsm import LinearFSM
+from .yaml_fsm import YamlFSM

lib/tfw/components/__init__.py

@@ -8,3 +8,4 @@ from .ide_event_handler import IdeEventHandler
 from .history_monitor import HistoryMonitor, BashMonitor, GDBMonitor
 from .terminal_commands import TerminalCommands
 from .log_monitoring_event_handler import LogMonitoringEventHandler
+from .fsm_managing_event_handler import FSMManagingEventHandler

lib/tfw/components/fsm_managing_event_handler.py

@@ -0,0 +1,56 @@
+# Copyright (C) 2018 Avatao.com Innovative Learning Kft.
+# All Rights Reserved. See LICENSE file for details.
+
+from tfw import BroadcastingEventHandler
+from tfw.config.logs import logging
+
+LOG = logging.getLogger(__name__)
+
+
+class FSMManagingEventHandler(BroadcastingEventHandler):
+    def __init__(self, key, fsm_type):
+        super().__init__(key)
+        self.fsm = fsm_type()
+        self._fsm_updater = FSMUpdater(self.fsm)
+
+        self.command_handlers = {
+            'trigger': self.handle_trigger,
+            'update':  self.handle_update
+        }
+
+    def handle_event(self, message):
+        try:
+            data = message['data']
+            message['data'] = self.command_handlers[data['command']](data)
+            return message
+        except KeyError:
+            LOG.error('IGNORING MESSAGE: Invalid message received: %s', message)
+
+    def handle_trigger(self, data):
+        self.fsm.step(data['value'])
+        return self.with_fsm_update(data)
+
+    def with_fsm_update(self, data):
+        return {
+            **data,
+            **self._fsm_updater.get_fsm_state_and_transitions()
+        }
+
+    def handle_update(self, data):
+        return self.with_fsm_update(data)
+
+
+class FSMUpdater:
+    def __init__(self, fsm):
+        self.fsm = fsm
+
+    def get_fsm_state_and_transitions(self):
+        state = self.fsm.state
+        valid_transitions = [
+            {'trigger': trigger}
+            for trigger in self.fsm.get_triggers(self.fsm.state)
+        ]
+        return {
+            'current_state': state,
+            'valid_transitions': valid_transitions
+        }

lib/tfw/event_handler_base.py

@@ -2,9 +2,13 @@
 # All Rights Reserved. See LICENSE file for details.
 
 from abc import ABC, abstractmethod
+from json import dumps
+from hashlib import md5
 
-from tfw.networking import deserialize_tfw_msg
 from tfw.networking.event_handlers import ServerConnector
+from tfw.config.logs import logging
+
+LOG = logging.getLogger(__name__)
 
 
 class EventHandlerBase(ABC):
@@ -20,22 +24,23 @@ class EventHandlerBase(ABC):
         self.subscribe(self.key, 'reset')
         self.server_connector.register_callback(self.event_handler_callback)
 
-    def event_handler_callback(self, msg_parts):
+    def event_handler_callback(self, message):
         """
         Callback that is invoked when receiving a message.
         Dispatches messages to handler methods and sends
         a response back in case the handler returned something.
         This is subscribed in __init__().
         """
-        message = deserialize_tfw_msg(*msg_parts)
         response = self.dispatch_handling(message)
         if response:
-            response['key'] = message['key']
             self.server_connector.send(response)
 
     def dispatch_handling(self, message):
         """
         Used to dispatch messages to their specific handlers.
+
+        :param message: the message received
+        :returns: the message to send back
         """
         if message['key'] != 'reset':
             return self.handle_event(message)
@@ -47,6 +52,7 @@ class EventHandlerBase(ABC):
         Abstract method that implements the handling of messages.
 
         :param message: the message received
+        :returns: the message to send back
         """
         raise NotImplementedError
 
@@ -56,6 +62,7 @@ class EventHandlerBase(ABC):
         Usually 'reset' events receive some sort of special treatment.
 
         :param message: the message received
+        :returns: the message to send back
         """
         return None
 
@@ -102,3 +109,38 @@ class TriggeredEventHandler(EventHandlerBase, ABC):
         if message.get('trigger') == self.trigger:
             return super().dispatch_handling(message)
         return None
+
+
+class BroadcastingEventHandler(EventHandlerBase, ABC):
+    # pylint: disable=abstract-method
+    """
+    Abstract base class for EventHandlers which broadcast responses
+    and intelligently ignore their own broadcasted messages they receive.
+    """
+    def __init__(self, key):
+        super().__init__(key)
+        self.own_message_hashes = []
+
+    def event_handler_callback(self, message):
+        message_hash = self.hash_message(message)
+
+        if message_hash in self.own_message_hashes:
+            self.own_message_hashes.remove(message_hash)
+            return
+
+        response = self.dispatch_handling(message)
+        if response:
+            self.own_message_hashes.append(self.hash_message(response))
+            self.server_connector.send(self.make_broadcast_message(response))
+
+    @staticmethod
+    def hash_message(message):
+        message_bytes = dumps(message, sort_keys=True).encode()
+        return md5(message_bytes).hexdigest()
+
+    @staticmethod
+    def make_broadcast_message(message):
+        return {
+            'key': 'broadcast',
+            'data': message
+        }

lib/tfw/fsm_base.py

@@ -1,27 +1,32 @@
 # Copyright (C) 2018 Avatao.com Innovative Learning Kft.
 # All Rights Reserved. See LICENSE file for details.
 
-from typing import List
+from collections import defaultdict
 
-from transitions import Machine
+from transitions import Machine, MachineError
 
 from tfw.mixins import CallbackMixin
+from tfw.config.logs import logging
+
+LOG = logging.getLogger(__name__)
 
 
-class FSMBase(CallbackMixin):
+class FSMBase(Machine, CallbackMixin):
     """
     A general FSM base class you can inherit from to track user progress.
     See linear_fsm.py for an example use-case.
-    TFW the transitions library for state machines, please refer to their
+    TFW uses the transitions library for state machines, please refer to their
     documentation for more information on creating your own machines:
     https://github.com/pytransitions/transitions
     """
     states, transitions = [], []
 
-    def __init__(self, initial: str = None, accepted_states: List[str] = None):
+    def __init__(self, initial=None, accepted_states=None):
         self.accepted_states = accepted_states or [self.states[-1]]
-        self.machine = Machine(
+        self.trigger_predicates = defaultdict(list)
-            model=self,
+
+        Machine.__init__(
+            self,
             states=self.states,
             transitions=self.transitions,
             initial=initial or self.states[0],
@@ -35,3 +40,26 @@ class FSMBase(CallbackMixin):
 
     def is_solved(self):
         return self.state in self.accepted_states  # pylint: disable=no-member
+
+    def subscribe_predicate(self, trigger, *predicates):
+        self.trigger_predicates[trigger].extend(predicates)
+
+    def unsubscribe_predicate(self, trigger, *predicates):
+        self.trigger_predicates[trigger] = [
+            predicate
+            for predicate in self.trigger_predicates[trigger]
+            not in predicates
+        ]
+
+    def step(self, trigger):
+        predicate_results = (
+            predicate()
+            for predicate in self.trigger_predicates[trigger]
+        )
+
+        # TODO: think about what could we do when this prevents triggering
+        if all(predicate_results):
+            try:
+                self.trigger(trigger)
+            except (AttributeError, MachineError):
+                LOG.debug('FSM failed to execute nonexistent trigger: "%s"', trigger)

lib/tfw/mixins/callback_mixin.py

@@ -21,6 +21,14 @@ class CallbackMixin:
         fun = partial(callback, *args, **kwargs)
         self._callbacks.append(fun)
 
+    def subscribe_callbacks(self, *callbacks):
+        """
+        Subscribe a list of callbacks to incoke once an event is triggered.
+        :param callbacks: callbacks to be subscribed
+        """
+        for callback in callbacks:
+            self.subscribe_callback(callback)
+
     def unsubscribe_callback(self, callback):
         self._callbacks.remove(callback)
 

lib/tfw/networking/__init__.py

@@ -1,7 +1,7 @@
 # Copyright (C) 2018 Avatao.com Innovative Learning Kft.
 # All Rights Reserved. See LICENSE file for details.
 
-from .serialization import serialize_tfw_msg, deserialize_tfw_msg, validate_message
+from .serialization import serialize_tfw_msg, deserialize_tfw_msg, with_deserialize_tfw_msg
 from .zmq_connector_base import ZMQConnectorBase
 # from .controller_connector import ControllerConnector # TODO: readd once controller stuff is resolved
 from .message_sender import MessageSender

lib/tfw/networking/event_handlers/server_connector.py

@@ -6,9 +6,12 @@ from functools import partial
 import zmq
 from zmq.eventloop.zmqstream import ZMQStream
 
-from tfw.networking import serialize_tfw_msg
+from tfw.networking import serialize_tfw_msg, with_deserialize_tfw_msg
 from tfw.networking import ZMQConnectorBase
 from tfw.config import TFWENV
+from tfw.config.logs import logging
+
+LOG = logging.getLogger(__name__)
 
 
 class ServerDownlinkConnector(ZMQConnectorBase):
@@ -20,7 +23,10 @@ class ServerDownlinkConnector(ZMQConnectorBase):
 
         self.subscribe = partial(self._zmq_sub_socket.setsockopt_string, zmq.SUBSCRIBE)
         self.unsubscribe = partial(self._zmq_sub_socket.setsockopt_string, zmq.UNSUBSCRIBE)
-        self.register_callback = self._zmq_sub_stream.on_recv
+
+    def register_callback(self, callback):
+        callback = with_deserialize_tfw_msg(callback)
+        self._zmq_sub_stream.on_recv(callback)
 
 
 class ServerUplinkConnector(ZMQConnectorBase):

lib/tfw/networking/serialization.py

@@ -22,10 +22,7 @@ The purpose of this module is abstracting away this low level behaviour.
 """
 
 import json
-
+from functools import wraps
-
-def validate_message(message):
-    return 'key' in message
 
 
 def serialize_tfw_msg(message):
@@ -35,6 +32,14 @@ def serialize_tfw_msg(message):
     return _serialize_all(message['key'], message)
 
 
+def with_deserialize_tfw_msg(fun):
+    @wraps(fun)
+    def wrapper(message_parts):
+        message = deserialize_tfw_msg(*message_parts)
+        return fun(message)
+    return wrapper
+
+
 def deserialize_tfw_msg(*args):
     """
     Return message from TFW multipart data

lib/tfw/networking/server/__init__.py

@@ -3,5 +3,4 @@
 
 from .event_handler_connector import EventHandlerConnector, EventHandlerUplinkConnector, EventHandlerDownlinkConnector
 from .tfw_server import TFWServer
-from .zmq_websocket_handler import ZMQWebSocketProxy
 # from .controller_responder import ControllerResponder  # TODO: readd once controller stuff is resolved

lib/tfw/networking/server/event_handler_connector.py

@@ -4,7 +4,7 @@
 import zmq
 from zmq.eventloop.zmqstream import ZMQStream
 
-from tfw.networking import ZMQConnectorBase, serialize_tfw_msg
+from tfw.networking import ZMQConnectorBase, serialize_tfw_msg, with_deserialize_tfw_msg
 from tfw.config import TFWENV
 from tfw.config.logs import logging
 
@@ -32,6 +32,7 @@ class EventHandlerUplinkConnector(ZMQConnectorBase):
 
 class EventHandlerConnector(EventHandlerDownlinkConnector, EventHandlerUplinkConnector):
     def register_callback(self, callback):
+        callback = with_deserialize_tfw_msg(callback)
         self._zmq_pull_stream.on_recv(callback)
 
     def send_message(self, message: dict):

lib/tfw/networking/server/tfw_server.py

@@ -1,15 +1,12 @@
 # Copyright (C) 2018 Avatao.com Innovative Learning Kft.
 # All Rights Reserved. See LICENSE file for details.
 
-from collections import defaultdict
-
 from tornado.web import Application
 
-from tfw.networking import MessageSender
 from tfw.networking.event_handlers import ServerUplinkConnector
 from tfw.networking.server import EventHandlerConnector
 from tfw.config.logs import logging
-from .zmq_websocket_handler import ZMQWebSocketProxy
+from .zmq_websocket_proxy import ZMQWebSocketProxy
 
 LOG = logging.getLogger(__name__)
 
@@ -18,117 +15,29 @@ class TFWServer:
     """
     This class handles the proxying of messages between the frontend and event handers.
     It proxies messages from the "/ws" route to all event handlers subscribed to a ZMQ
-    SUB socket. It also manages an FSM you can define as a constructor argument.
+    SUB socket.
     """
-    def __init__(self, fsm_type):
+    def __init__(self):
-        """
-        :param fsm_type: the type of FSM you want TFW to use
-        """
-        self._fsm = fsm_type()
-        self._fsm_updater = FSMUpdater(self._fsm)
-        self._fsm_manager = FSMManager(self._fsm)
-        self._fsm.subscribe_callback(self._fsm_updater.update)
         self._event_handler_connector = EventHandlerConnector()
+        self._uplink_connector = ServerUplinkConnector()
 
         self.application = Application([(
             r'/ws', ZMQWebSocketProxy,{
-                'make_eventhandler_message': self.make_eventhandler_message,
+                'event_handler_connector': self._event_handler_connector,
-                'proxy_filter': self.proxy_filter,
+                'message_handlers': [self.handle_trigger]
-                'handle_trigger': self.handle_trigger,
-                'event_handler_connector': self._event_handler_connector
             })]
         )
-        # self.controller_responder = ControllerResponder(self.fsm)
-        # TODO: add this once controller stuff is resolved
-
-    @property
-    def fsm(self):
-        return self._fsm
-
-    @property
-    def fsm_manager(self):
-        return self._fsm_manager
-
-    def make_eventhandler_message(self, message):
-        self.trigger_fsm(message)
-        message['FSMUpdate'] = self._fsm_updater.get_fsm_state_and_transitions()
-        return message
 
     def handle_trigger(self, message):
+        if 'trigger' in message:
             LOG.debug('Executing handler for trigger "%s"', message.get('trigger', ''))
-        self.trigger_fsm(message)
+            self._uplink_connector.send_to_eventhandler({
-
+                'key': 'fsm',
-    def trigger_fsm(self, message):
+                'data': {
-        trigger = message.get('trigger', '')
+                    'command': 'trigger',
-        try:
+                    'value': message.get('trigger', '')
-            self._fsm_manager.trigger(trigger, message)
+                }
-        except AttributeError:
+            })
-            LOG.debug('FSM failed to execute nonexistent trigger: "%s"', trigger)
-
-    def proxy_filter(self, message):
-        # pylint: disable=unused-argument,no-self-use
-        return True
 
     def listen(self, port):
         self.application.listen(port)
-
-
-class FSMManager:
-    def __init__(self, fsm):
-        self._fsm = fsm
-        self.trigger_predicates = defaultdict(list)
-        self.messenge_sender = MessageSender()
-
-    @property
-    def fsm(self):
-        return self._fsm
-
-    def trigger(self, trigger, message):
-        predicate_results = []
-        for predicate in self.trigger_predicates[trigger]:
-            success, message = predicate(message)
-            predicate_results.append(success)
-            self.messenge_sender.send('FSM', message)
-
-        if all(predicate_results):
-            try:
-                self.fsm.trigger(trigger, message=message)
-            except AttributeError:
-                LOG.debug('FSM failed to execute nonexistent trigger: "%s"', trigger)
-
-    def subscribe_predicate(self, trigger, *predicates):
-        self.trigger_predicates[trigger].extend(predicates)
-
-    def unsubscribe_predicate(self, trigger, *predicates):
-        self.trigger_predicates[trigger] = [
-            predicate
-            for predicate in self.trigger_predicates[trigger]
-            not in predicates
-        ]
-
-
-class FSMUpdater:
-    def __init__(self, fsm):
-        self.fsm = fsm
-        self.uplink = ServerUplinkConnector()
-
-    def update(self, kwargs_dict):
-        # pylint: disable=unused-argument
-        self.uplink.send(self.generate_fsm_update())
-
-    def generate_fsm_update(self):
-        return {
-            'key': 'FSMUpdate',
-            'data': self.get_fsm_state_and_transitions()
-        }
-
-    def get_fsm_state_and_transitions(self):
-        state = self.fsm.state
-        valid_transitions = [
-            {'trigger': trigger}
-            for trigger in self.fsm.machine.get_triggers(self.fsm.state)
-        ]
-        return {
-            'current_state': state,
-            'valid_transitions': valid_transitions
-        }

lib/tfw/networking/server/zmq_websocket_handler.py

@@ -1,91 +0,0 @@
-# Copyright (C) 2018 Avatao.com Innovative Learning Kft.
-# All Rights Reserved. See LICENSE file for details.
-
-import json
-from abc import ABC, abstractmethod
-
-from tornado.websocket import WebSocketHandler
-
-from tfw.networking import deserialize_tfw_msg, validate_message
-from tfw.config.logs import logging
-
-LOG = logging.getLogger(__name__)
-
-
-class ZMQWebSocketHandler(WebSocketHandler, ABC):
-    instances = set()
-
-    def initialize(self, **kwargs): # pylint: disable=arguments-differ
-        self._event_handler_connector = kwargs['event_handler_connector']
-
-    def prepare(self):
-        ZMQWebSocketHandler.instances.add(self)
-
-    def on_close(self):
-        ZMQWebSocketHandler.instances.remove(self)
-
-    def open(self, *args, **kwargs):
-        LOG.debug('WebSocket connection initiated')
-        self._event_handler_connector.register_callback(self.zmq_callback)
-
-    def zmq_callback(self, msg_parts):
-        keyhandlers = {'mirror': self.mirror}
-
-        message = deserialize_tfw_msg(*msg_parts)
-        LOG.debug('Received on pull socket: %s', message)
-        if not validate_message(message):
-            return
-
-        self.handle_trigger(message)
-        if message['key'] not in keyhandlers:
-            for instance in ZMQWebSocketHandler.instances:
-                instance.write_message(message)
-        else:
-            try:
-                keyhandlers[message['key']](message)
-            except KeyError:
-                LOG.error('Invalid mirror message format! Ignoring.')
-
-    def mirror(self, message):
-        message = message['data']
-        self._event_handler_connector.send_message(message)
-
-    def on_message(self, message):
-        LOG.debug('Received on WebSocket: %s', message)
-        if validate_message(message):
-            self.send_message(self.make_eventhandler_message(message))
-
-    @abstractmethod
-    def make_eventhandler_message(self, message):
-        raise NotImplementedError
-
-    def send_message(self, message: dict):
-        self._event_handler_connector.send_message(message)
-
-    @abstractmethod
-    def handle_trigger(self, message):
-        raise NotImplementedError
-
-    # much secure, very cors, wow
-    def check_origin(self, origin):
-        return True
-
-
-class ZMQWebSocketProxy(ZMQWebSocketHandler):
-    # pylint: disable=abstract-method
-    def initialize(self, **kwargs): # pylint: disable=arguments-differ
-        super(ZMQWebSocketProxy, self).initialize(**kwargs)
-        self._make_eventhandler_message = kwargs['make_eventhandler_message']
-        self._proxy_filter = kwargs['proxy_filter']
-        self._handle_trigger = kwargs['handle_trigger']
-
-    def on_message(self, message):
-        message = json.loads(message)
-        if self._proxy_filter(message):
-            super().on_message(message)
-
-    def make_eventhandler_message(self, message):
-        return self._make_eventhandler_message(message)
-
-    def handle_trigger(self, message):
-        self._handle_trigger(message)

lib/tfw/networking/server/zmq_websocket_proxy.py

@@ -0,0 +1,121 @@
+# Copyright (C) 2018 Avatao.com Innovative Learning Kft.
+# All Rights Reserved. See LICENSE file for details.
+
+import json
+
+from tornado.websocket import WebSocketHandler
+
+from tfw.mixins import CallbackMixin
+from tfw.config.logs import logging
+
+LOG = logging.getLogger(__name__)
+
+
+class ZMQWebSocketProxy(WebSocketHandler):
+    instances = set()
+
+    def initialize(self, **kwargs): # pylint: disable=arguments-differ
+        self._event_handler_connector = kwargs['event_handler_connector']
+        self._message_handlers = kwargs.get('message_handlers', [])
+        self._proxy_filters = kwargs.get('proxy_filters', [])
+
+        self.proxy_eventhandler_to_websocket = TFWProxy(
+            self.send_eventhandler_message,
+            self.send_websocket_message
+        )
+        self.proxy_websocket_to_eventhandler = TFWProxy(
+            self.send_websocket_message,
+            self.send_eventhandler_message
+        )
+
+        proxies = (self.proxy_eventhandler_to_websocket, self.proxy_websocket_to_eventhandler)
+        for proxy in proxies:
+            proxy.proxy_filters.subscribe_callbacks(*self._proxy_filters)
+            proxy.proxy_callbacks.subscribe_callbacks(*self._message_handlers)
+
+    def prepare(self):
+        ZMQWebSocketProxy.instances.add(self)
+
+    def on_close(self):
+        ZMQWebSocketProxy.instances.remove(self)
+
+    def open(self, *args, **kwargs):
+        LOG.debug('WebSocket connection initiated')
+        self._event_handler_connector.register_callback(self.eventhander_callback)
+
+    def eventhander_callback(self, message):
+        """
+        Invoked on ZMQ messages from event handlers.
+        """
+        LOG.debug('Received on pull socket: %s', message)
+        self.proxy_eventhandler_to_websocket(message)
+
+    def on_message(self, message):
+        """
+        Invoked on WS messages from frontend.
+        """
+        message = json.loads(message)
+        LOG.debug('Received on WebSocket: %s', message)
+        self.proxy_websocket_to_eventhandler(message)
+
+    def send_eventhandler_message(self, message):
+        self._event_handler_connector.send_message(message)
+
+    @staticmethod
+    def send_websocket_message(message):
+        for instance in ZMQWebSocketProxy.instances:
+            instance.write_message(message)
+
+    # much secure, very cors, wow
+    def check_origin(self, origin):
+        return True
+
+
+class TFWProxy:
+    def __init__(self, to_source, to_destination):
+        self.to_source = to_source
+        self.to_destination = to_destination
+
+        self.proxy_filters = CallbackMixin()
+        self.proxy_callbacks = CallbackMixin()
+
+        self.proxy_filters.subscribe_callback(self.validate_message)
+
+        self.keyhandlers = {
+            'mirror':    self.mirror,
+            'broadcast': self.broadcast
+        }
+
+    @staticmethod
+    def validate_message(message):
+        if 'key' not in message:
+            raise ValueError('Invalid TFW message format!')
+
+    def __call__(self, message):
+        try:
+            self.proxy_filters._execute_callbacks(message)
+        except ValueError:
+            LOG.exception('Invalid TFW message received!')
+            return
+
+        self.proxy_callbacks._execute_callbacks(message)
+
+        if message['key'] not in self.keyhandlers:
+            self.to_destination(message)
+        else:
+            handler = self.keyhandlers[message['key']]
+            try:
+                handler(message)
+            except KeyError:
+                LOG.error('Invalid "%s" message format! Ignoring.', handler.__name__)
+
+    def mirror(self, message):
+        message = message['data']
+        LOG.debug('Mirroring message: %s', message)
+        self.to_source(message)
+
+    def broadcast(self, message):
+        message = message['data']
+        LOG.debug('Broadcasting message: %s', message)
+        self.to_source(message)
+        self.to_destination(message)

lib/tfw/yaml_fsm.py

@@ -0,0 +1,64 @@
+from subprocess import Popen, run
+from functools import partial
+from contextlib import suppress
+
+import yaml
+from transitions import State
+
+from tfw import FSMBase
+
+
+class YamlFSM(FSMBase):
+    def __init__(self, config_file):
+        self.config = self.parse_config(config_file)
+        self.setup_states()
+        super().__init__()  # FSMBase.__init__() requires states
+        self.setup_transitions()
+
+    @staticmethod
+    def parse_config(config_file):
+        with open(config_file, 'r') as ifile:
+            return yaml.safe_load(ifile)
+
+    def setup_states(self):
+        self.for_config_states_and_transitions_do(self.wrap_callbacks_with_subprocess_call)
+        self.states = [State(**state) for state in self.config['states']]
+
+    def setup_transitions(self):
+        self.for_config_states_and_transitions_do(self.subscribe_and_remove_predicates)
+        for transition in self.config['transitions']:
+            self.add_transition(**transition)
+
+    def for_config_states_and_transitions_do(self, what):
+        for array in ('states', 'transitions'):
+            for json_obj in self.config[array]:
+                what(json_obj)
+
+    @staticmethod
+    def wrap_callbacks_with_subprocess_call(json_obj):
+        topatch = ('on_enter', 'on_exit', 'prepare', 'before', 'after')
+        for key in json_obj:
+            if key in topatch:
+                json_obj[key] = partial(run_command_async, json_obj[key])
+
+    def subscribe_and_remove_predicates(self, json_obj):
+        if 'predicates' in json_obj:
+            for predicate in json_obj['predicates']:
+                    self.subscribe_predicate(
+                        json_obj['trigger'],
+                        partial(
+                            command_statuscode_is_zero,
+                            predicate
+                        )
+                    )
+                
+        with suppress(KeyError):
+            json_obj.pop('predicates')
+
+
+def run_command_async(command, event):
+    Popen(command, shell=True)
+
+
+def command_statuscode_is_zero(command):
+    return run(command, shell=True).returncode == 0

requirements.txt

@@ -3,3 +3,4 @@ pyzmq==17.0.0
 transitions==0.6.4
 terminado==0.8.1
 watchdog==0.8.3
+PyYAML==3.12

supervisor/components/tfw_server.conf

@@ -0,0 +1,4 @@
+[program:tfwserver]
+user=root
+directory=%(ENV_TFW_SERVER_DIR)s
+command=python3 tfw_server.py

supervisor/tfw_server.py

@@ -0,0 +1,9 @@
+from tornado.ioloop import IOLoop
+
+from tfw.networking import TFWServer
+from tfw.config import TFWENV
+
+
+if __name__ == '__main__':
+    TFWServer().listen(TFWENV.WEB_PORT)
+    IOLoop.instance().start()