Add first experiment with websockets, for datasync status page

tailbone/views/asgi/__init__.py

@@ -0,0 +1,70 @@
+# -*- coding: utf-8; -*-
+################################################################################
+#
+#  Rattail -- Retail Software Framework
+#  Copyright © 2010-2022 Lance Edgar
+#
+#  This file is part of Rattail.
+#
+#  Rattail 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.
+#
+#  Rattail 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
+#  Rattail.  If not, see <http://www.gnu.org/licenses/>.
+#
+################################################################################
+"""
+ASGI Views
+"""
+
+from __future__ import unicode_literals, absolute_import
+
+import http.cookies
+
+from beaker.cache import clsmap
+from beaker.session import SessionObject, SignedCookie
+
+
+class WebsocketView(object):
+
+    def __init__(self, registry):
+        self.registry = registry
+
+    async def get_user_session(self, scope):
+        settings = self.registry.settings
+        beaker_key = settings['beaker.session.key']
+        beaker_secret = settings['beaker.session.secret']
+        beaker_type = settings['beaker.session.type']
+        beaker_data_dir = settings['beaker.session.data_dir']
+        beaker_lock_dir = settings['beaker.session.lock_dir']
+
+        # get ahold of session identifier cookie
+        headers = dict(scope['headers'])
+        cookie = headers.get(b'cookie')
+        if not cookie:
+            return
+        cookie = cookie.decode('utf_8')
+        cookie = http.cookies.SimpleCookie(cookie)
+        morsel = cookie[beaker_key]
+
+        # simulate pyramid_beaker logic to get at the session
+        cookieheader = morsel.output(header='')
+        cookie = SignedCookie(beaker_secret, input=cookieheader)
+        session_id = cookie[beaker_key].value
+        request = {'cookie': cookieheader}
+        session = SessionObject(
+            request,
+            id=session_id,
+            key=beaker_key,
+            namespace_class=clsmap[beaker_type],
+            data_dir=beaker_data_dir,
+            lock_dir=beaker_lock_dir)
+
+        return session

tailbone/views/asgi/datasync.py

@@ -0,0 +1,113 @@
+# -*- coding: utf-8; -*-
+################################################################################
+#
+#  Rattail -- Retail Software Framework
+#  Copyright © 2010-2022 Lance Edgar
+#
+#  This file is part of Rattail.
+#
+#  Rattail 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.
+#
+#  Rattail 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
+#  Rattail.  If not, see <http://www.gnu.org/licenses/>.
+#
+################################################################################
+"""
+DataSync Views
+"""
+
+from __future__ import unicode_literals, absolute_import
+
+import asyncio
+import json
+
+from tailbone.views.asgi import WebsocketView
+
+
+class DatasyncWS(WebsocketView):
+
+    async def status(self, scope, receive, send):
+        rattail_config = self.registry['rattail_config']
+        app = rattail_config.get_app()
+        model = app.model
+        auth_handler = app.get_auth_handler()
+        datasync_handler = app.get_datasync_handler()
+
+        authorized = False
+        user_session = await self.get_user_session(scope)
+        if user_session:
+            user_uuid = user_session.get('auth.userid')
+            session = app.make_session()
+
+            user = None
+            if user_uuid:
+                user = session.query(model.User).get(user_uuid)
+
+            # figure out if user is authorized for this websocket
+            permission = 'datasync.status'
+            authorized = auth_handler.has_permission(session, user, permission)
+            session.close()
+
+        # wait for client to connect
+        message = await receive()
+        assert message['type'] == 'websocket.connect'
+
+        # allow or deny access, per authorization
+        if authorized:
+            await send({'type': 'websocket.accept'})
+        else: # forbidden
+            await send({'type': 'websocket.close'})
+            return
+
+        # this tracks when client disconnects
+        state = {'disconnected': False}
+
+        async def wait_for_disconnect():
+            message = await receive()
+            if message['type'] == 'websocket.disconnect':
+                state['disconnected'] = True
+
+        # watch for client disconnect, while we do other things
+        asyncio.create_task(wait_for_disconnect())
+
+        # do the rest forever, until client disconnects
+        while not state['disconnected']:
+
+            # give client latest supervisor process info
+            info = datasync_handler.get_supervisor_process_info()
+            await send({'type': 'websocket.send',
+                        'subtype': 'datasync.supervisor_process_info',
+                        'text': json.dumps(info)})
+
+            # pause for 1 second
+            await asyncio.sleep(1)
+
+    @classmethod
+    def defaults(cls, config):
+        cls._defaults(config)
+
+    @classmethod
+    def _defaults(cls, config):
+
+        # status
+        config.add_tailbone_websocket('datasync.status',
+                                      cls, attr='status')
+
+
+def defaults(config, **kwargs):
+    base = globals()
+
+    DatasyncWS = kwargs.get('DatasyncWS', base['DatasyncWS'])
+    DatasyncWS.defaults(config)
+
+
+def includeme(config):
+    defaults(config)

tailbone/views/datasync.py

@@ -40,6 +40,7 @@ from rattail.util import simple_error
 
 from tailbone.views import MasterView
 from tailbone.util import raw_datetime
+from tailbone.config import should_expose_websockets
 
 
 log = logging.getLogger(__name__)
@@ -400,6 +401,19 @@ class DataSyncChangeView(MasterView):
 DataSyncChangesView = DataSyncChangeView
 
 
-def includeme(config):
+def defaults(config, **kwargs):
+    base = globals()
+    rattail_config = config.registry['rattail_config']
+
+    DataSyncThreadView = kwargs.get('DataSyncThreadView', base['DataSyncThreadView'])
     DataSyncThreadView.defaults(config)
+
+    DataSyncChangeView = kwargs.get('DataSyncChangeView', base['DataSyncChangeView'])
     DataSyncChangeView.defaults(config)
+
+    if should_expose_websockets(rattail_config):
+        config.include('tailbone.views.asgi.datasync')
+
+
+def includeme(config):
+    defaults(config)