class Store(object):
KEEP_ALIVE_TIMEOUT = 60 # Seconds
OPSLOG_SIZE = 1000000 # 1 MB
def __init__(self):
self.client = None
self.db = None
self.subscriptions = {}
def connect(self, uri, db=None, w=1, j=True, **options):
io_loop = options.get('io_loop', None)
self.client = MotorClient(uri, w=w, j=j, **options).open_sync()
self.client_sync = self.client.sync_client()
db = db or uri_parser.parse_uri(uri)['database']
if not db:
raise ConfigurationError('No database defined in uri')
self.db = self.client[db]
self.db_sync = self.client_sync[db]
#PeriodicCallback(self.client.alive, Store.KEEP_ALIVE_TIMEOUT,
# io_loop=io_loop).start()
def opslog(self, collection):
collection_opslog = '{0}.opslog'.format(collection)
try:
defer(self.db.create_collection, collection_opslog,
capped=True, size=Store.OPSLOG_SIZE)
# Prime opslog as tailable cursors die on empty collections
defer(self.db[collection_opslog].insert, {})
except CollectionInvalid:
pass
return self.db[collection_opslog]
def _monitor(self, collection, query_key, query):
# TODO: Handle doc removal
# TODO: Batch requests
try:
query = {'doc.{0}'.format(k): v for k, v in query.items()}
query['_id'] = {'$gt': ObjectId.from_datetime(datetime.utcnow())}
opslog = self.opslog(collection)
cursor = opslog.find(query, tailable=True, await_data=True)
item = tail(cursor.tail)
while True:
ops, err = next(item)
if err:
raise err
print(ops)
if not ops['doc'].get('_id'):
_log.warn('Opslog for collection "{0}" contains a '
'document with no _id'.format(collection))
continue
if ops['op'] == 'insert':
doc = ops['doc']
elif ops['op'] == 'update':
doc = ops['updated']
response = json.dumps({
'response': 'subscribe',
'query': query_key,
'collection': collection,
'result': [doc],
})
for request in list(self.subscriptions[query_key]):
if request.is_closed:
self.subscriptions[query_key].remove(request)
continue
request.send(response)
if not self.subscriptions[query_key]:
break
except Exception as e:
_log.exception(e)
finally:
if query_key in self.subscriptions:
del self.subscriptions[query_key]
def subscribe(self, request, collection, query_key):
# TODO: Inject security policies/adapters/transforms here
query = json.loads(query_key)
if query_key in self.subscriptions:
self.subscriptions[query_key].add(request)
else:
Greenlet(self._monitor).switch(collection, query_key, query)
self.subscriptions[query_key] = {request}
docs = defer(self.db[collection].find(query).to_list, 1000)
request.send(json.dumps({
'response': 'subscribe',
'query': query_key,
'collection': collection,
'result': docs
}))
def __getattr__(self, name):
return self[name]
def __getitem__(self, name):
return Collection(model, name)
