Adding websocket event publisher

brew_view/__init__.py

@@ -16,7 +16,8 @@
 from bg_utils.event_publisher import EventPublishers
 from bg_utils.pika import TransientPikaClient
 from bg_utils.plugin_logging_loader import PluginLoggingLoader
-from brew_view.publishers import MongoPublisher, RequestPublisher, TornadoPikaPublisher
+from brew_view.publishers import (MongoPublisher, RequestPublisher,
+                                  TornadoPikaPublisher, WebsocketPublisher)
 from brew_view.specification import get_default_logging_config
 from brewtils.schemas import ParameterSchema, CommandSchema, InstanceSchema, SystemSchema, \
     RequestSchema, PatchSchema, LoggingConfigSchema, EventSchema, QueueSchema
@@ -51,6 +52,12 @@ def setup_brew_view(spec, cli_args):
     _setup_application()
 
 
+def shutdown():
+    """Close any open websocket connections"""
+    from brew_view.controllers import EventSocket
+    EventSocket.shutdown()
+
+
 def load_plugin_logging_config(input_config):
     global plugin_logging_config
 
@@ -86,7 +93,7 @@ def _setup_tornado_app():
     from brew_view.controllers import AdminAPI, CommandAPI, CommandListAPI, ConfigHandler, \
         InstanceAPI, QueueAPI, QueueListAPI, RequestAPI, RequestListAPI, SystemAPI, SystemListAPI, \
         VersionHandler, SpecHandler, SwaggerConfigHandler, OldAdminAPI, OldQueueAPI, \
-        OldQueueListAPI, LoggingConfigAPI, EventPublisherAPI
+        OldQueueListAPI, LoggingConfigAPI, EventPublisherAPI, EventSocket
 
     prefix = config.web.url_prefix
     static_base = os.path.join(os.path.dirname(__file__), 'static', 'dist')
@@ -116,13 +123,23 @@ def _setup_tornado_app():
 
     # And these do not
     unpublished_url_specs = [
+        # These are a little special - unpublished but still versioned
+        # The swagger spec
+        (r'{0}api/v1/spec/?'.format(prefix), SpecHandler),
+        # Events websocket
+        (r'{0}api/v1/socket/events/?'.format(prefix), EventSocket),
+
+        # Version / configs
+        (r'{0}version/?'.format(prefix), VersionHandler),
         (r'{0}config/?'.format(prefix), ConfigHandler),
         (r'{0}config/swagger/?'.format(prefix), SwaggerConfigHandler),
-        (r'{0}version/?'.format(prefix), VersionHandler),
-        (r'{0}api/v1/spec/?'.format(prefix), SpecHandler),
+
+        # Not sure if these are really necessary
         (r'{0}'.format(prefix[:-1]), RedirectHandler, {"url": prefix}),
         (r'{0}swagger/(.*)'.format(prefix), StaticFileHandler,
             {'path': os.path.join(static_base, 'swagger')}),
+
+        # Static content
         (r'{0}(.*)'.format(prefix), StaticFileHandler,
             {'path': static_base, 'default_filename': 'index.html'})
     ]
@@ -184,9 +201,13 @@ def bg_thrift_context(async=True, **kwargs):
 
 
 def _setup_event_publishers(ssl_context):
+    from brew_view.controllers.event_api import EventSocket
 
     # Create the collection of event publishers and add concrete publishers to it
-    pubs = EventPublishers({'request': RequestPublisher(ssl_context=ssl_context)})
+    pubs = EventPublishers({
+        'request': RequestPublisher(ssl_context=ssl_context),
+        'websocket': WebsocketPublisher(EventSocket)
+    })
 
     if config.event.mongo.enable:
         pubs['mongo'] = MongoPublisher()

brew_view/__main__.py

@@ -23,6 +23,10 @@ def shutdown():
     brew_view.logger.info("Stopping server.")
     brew_view.server.stop()
 
+    # Shutdown everything short of the event loop
+    # (we need the event loop to publish the shutdown event)
+    brew_view.shutdown()
+
     # Publish shutdown notification
     brew_view.event_publishers.publish_event(Event(name=Events.BREWVIEW_STOPPED.name))
 

brew_view/controllers/__init__.py

@@ -13,4 +13,4 @@
 from brew_view.controllers.misc_controllers import ConfigHandler, VersionHandler, SpecHandler, \
     SwaggerConfigHandler
 from brew_view.controllers.logging_api import LoggingConfigAPI
-from brew_view.controllers.event_api import EventPublisherAPI
+from brew_view.controllers.event_api import EventPublisherAPI, EventSocket

brew_view/controllers/event_api.py

@@ -1,6 +1,9 @@
 import logging
 
+from tornado.websocket import WebSocketHandler
+
 import brew_view
+from bg_utils.parser import BeerGardenSchemaParser
 from brew_view.base_handler import BaseHandler
 from brewtils.schema_parser import SchemaParser
 
@@ -50,3 +53,43 @@ def post(self):
                 brew_view.event_publishers[publisher].publish_event(event)
 
         self.set_status(204)
+
+
+class EventSocket(WebSocketHandler):
+
+    logger = logging.getLogger(__name__)
+    parser = BeerGardenSchemaParser()
+
+    closing = False
+    listeners = set()
+
+    def check_origin(self, origin):
+        return True
+
+    def open(self):
+        if EventSocket.closing:
+            self.close(reason='Shutting down')
+        else:
+            EventSocket.listeners.add(self)
+
+    def on_close(self):
+        EventSocket.listeners.discard(self)
+
+    def on_message(self, message):
+        pass
+
+    @classmethod
+    def publish(cls, message):
+        # Don't bother if nobody is listening
+        if not len(cls.listeners):
+            return
+
+        for listener in cls.listeners:
+            listener.write_message(message)
+
+    @classmethod
+    def shutdown(cls):
+        EventSocket.closing = True
+
+        for listener in cls.listeners:
+            listener.close(reason='Shutting down')

brew_view/publishers.py

@@ -95,6 +95,18 @@ def _event_publish_args(self, event, **kwargs):
         return {'urls': urls} if urls else {}
 
 
+class WebsocketPublisher(BeergardenPublisher):
+    """Publisher implementation that publishes to a websocket"""
+
+    def __init__(self, socket_class):
+        BeergardenPublisher.__init__(self)
+
+        self._socket = socket_class
+
+    def publish(self, message, **kwargs):
+        self._socket.publish(message)
+
+
 class MongoPublisher(BeergardenPublisher):
     """Publisher implementation that 'publishes' to Mongo"""