Merge pull request #2 from sportstech/pubsub

Pubsub implementation

Author: bendemaree

README.md

@@ -9,13 +9,13 @@ Currently supports:
 
 # Installation instructions
 
-For instaling graphql-ws, just run this command in your shell
+For installing graphql-ws, just run this command in your shell
 
 ```bash
 pip install graphql-ws
 ```
 
-## Examples
+## Subscription Server
 
 ### aiohttp
 
@@ -63,90 +63,167 @@ async def subscriptions(request, ws):
 
 app.run(host="0.0.0.0", port=8000)
 ```
-
-And then, plug into a subscribable schema:
+### Gevent
+For setting up, just plug into your Gevent server.
 
 ```python
-import asyncio
-import graphene
+subscription_server = GeventSubscriptionServer(schema)
+app.app_protocol = lambda environ_path_info: 'graphql-ws'
 
+@sockets.route('/subscriptions')
+def echo_socket(ws):
+    subscription_server.handle(ws)
+    return []
+```
+### Django (with channels)
 
-class Query(graphene.ObjectType):
-    base = graphene.String()
+First `pip install channels` and add it to your django apps
 
+Then add the following to your settings.py
 
-class Subscription(graphene.ObjectType):
-    count_seconds = graphene.Float(up_to=graphene.Int())
+```python
+    CHANNELS_WS_PROTOCOLS = ["graphql-ws", ]
+    CHANNEL_LAYERS = {
+        "default": {
+            "BACKEND": "asgiref.inmemory.ChannelLayer",
+            "ROUTING": "django_subscriptions.urls.channel_routing",
+        },
 
-    async def resolve_count_seconds(root, info, up_to):
-        for i in range(up_to):
-            yield i
-            await asyncio.sleep(1.)
-        yield up_to
+    }
+```
+
+Add the channel routes to your Django server.
 
+```python
+from channels.routing import route_class
+from graphql_ws.django_channels import GraphQLSubscriptionConsumer
 
-schema = graphene.Schema(query=Query, subscription=Subscription)
+channel_routing = [
+    route_class(GraphQLSubscriptionConsumer, path=r"^/subscriptions"),
+]
 ```
 
-You can see a full example here: https://github.com/graphql-python/graphql-ws/tree/master/examples/aiohttp
+## Publish-Subscribe
+Included are several publish-subscribe (pubsub) classes for hooking
+up your mutations to your subscriptions. When a client makes a
+subscription, the pubsub can be used to map from one subscription name
+to one or more channel names to subscribe to the right channels.
+The subscription query will be re-run every time something is
+published to one of these channels. Using these classes, a
+subscription is just the result of a mutation. 
 
-### Gevent
+### Asyncio
 
-For setting up, just plug into your Gevent server.
+There are two pubsub classes for asyncio, one that is in-memory and the other
+that utilizes Redis (for production), via the [aredis](https://github.com/NoneGG/aredis) libary, which
+is a asynchronous port of the excellent [redis-py](https://github.com/andymccurdy/redis-py) library.
+
+The schema for asyncio would look something like this below:
 
 ```python
-subscription_server = GeventSubscriptionServer(schema)
-app.app_protocol = lambda environ_path_info: 'graphql-ws'
+import asyncio
+import graphene
 
-@sockets.route('/subscriptions')
-def echo_socket(ws):
-    subscription_server.handle(ws)
-    return []
+from graphql_ws.pubsub import AsyncioPubsub
+
+# create a new pubsub object; this class is in-memory and does
+# not utilze Redis
+pubsub = AsyncioPubsub()
+
+
+class MutationExample(graphene.Mutation):
+    class Arguments:
+        input_text = graphene.String()
+
+    output_text = graphene.String()
+
+    async def mutate(self, info, input_text):
+        # publish to the pubsub object before returning mutation
+        await pubsub.publish('BASE', input_text)
+        return MutationExample(output_text=input_text)
+
+
+class Mutations(graphene.ObjectType):
+    mutation_example = MutationExample.Field()
+
+
+class Subscription(graphene.ObjectType):
+    mutation_example = graphene.String()
+
+    async def resolve_mutation_example(root, info):
+        try:
+            # pubsub subscribe_to_channel method returns
+            # subscription id and an asyncio.Queue
+            sub_id, q = pubsub.subscribe_to_channel('BASE')
+            while True:
+                payload = await q.get()
+                yield payload
+        except asyncio.CancelledError:
+            # unsubscribe subscription id from channel
+            # when coroutine is cancelled
+            pubsub.unsubscribe('BASE', sub_id)
+
+schema = graphene.Schema(mutation=Mutations,
+                         subscription=Subscription)
 ```
 
-And then, plug into a subscribable schema:
+You can see a full asyncio example here: https://github.com/graphql-python/graphql-ws/tree/master/examples/aiohttp
+
+### Gevent
+
+There are two pubsub classes for Gevent as well, one that is
+in-memory and the other that utilizes Redis (for production), via
+[redis-py](https://github.com/andymccurdy/redis-py).
+
+Finally, plug into a subscribable schema:
 
 ```python
 import graphene
+
+from graphql_ws.pubsub import GeventRxRedisPubsub
 from rx import Observable
 
+# create a new pubsub object; in the case you'll need to
+# be running a redis-server instance in a separate process
+pubsub = GeventRxRedisPubsub()
 
-class Query(graphene.ObjectType):
-    base = graphene.String()
 
+class MutationExample(graphene.Mutation):
+    class Arguments:
+        input_text = graphene.String()
 
-class Subscription(graphene.ObjectType):
-    count_seconds = graphene.Float(up_to=graphene.Int())
+    output_text = graphene.String()
 
-    async def resolve_count_seconds(root, info, up_to=5):
-        return Observable.interval(1000)\
-                         .map(lambda i: "{0}".format(i))\
-                         .take_while(lambda i: int(i) <= up_to)
+    def mutate(self, info, input_text):
+        # publish to the pubsub before returning mutation
+        pubsub.publish('BASE', input_text)
+        return MutationExample(output_text=input_text)
 
 
-schema = graphene.Schema(query=Query, subscription=Subscription)
-```
+class Mutations(graphene.ObjectType):
+    mutation_example = MutationExample.Field()
 
-You can see a full example here: https://github.com/graphql-python/graphql-ws/tree/master/examples/flask_gevent
 
+class Subscription(graphene.ObjectType):
+    mutation_example = graphene.String()
 
-### Django Channels
+    def resolve_mutation_example(root, info):
+        # pubsub subscribe_to_channel method returns an observable
+        # when observable is disposed of, the subscription will
+        # be cleaned up and unsubscribed from
+        return pubsub.subscribe_to_channel('BASE')\
+                         .map(lambda i: "{0}".format(i))
 
 
-First `pip install channels` and it to your django apps
+schema = graphene.Schema(mutation=Mutations,
+                         subscription=Subscription)
+```
 
-Then add the following to your settings.py
+You can see a full example here: https://github.com/graphql-python/graphql-ws/tree/master/examples/flask_gevent
 
-```python
-    CHANNELS_WS_PROTOCOLS = ["graphql-ws", ]
-    CHANNEL_LAYERS = {
-        "default": {
-            "BACKEND": "asgiref.inmemory.ChannelLayer",
-            "ROUTING": "django_subscriptions.urls.channel_routing",
-        },
 
-    }
-```
+### Django (with channels)
+
 
 Setup your graphql schema
 
@@ -167,8 +244,8 @@ class Subscription(graphene.ObjectType):
 
 
     def resolve_count_seconds(
-        root, 
-        info, 
+        root,
+        info,
         up_to=5
     ):
         return Observable.interval(1000)\
@@ -192,14 +269,3 @@ GRAPHENE = {
     'SCHEMA': 'path.to.schema'
 }
 ```
-
-and finally add the channel routes
-
-```python
-from channels.routing import route_class
-from graphql_ws.django_channels import GraphQLSubscriptionConsumer
-
-channel_routing = [
-    route_class(GraphQLSubscriptionConsumer, path=r"^/subscriptions"),
-]
-```

examples/aiohttp/schema.py

@@ -2,10 +2,32 @@
 import asyncio
 import graphene
 
+from graphql_ws.pubsub import AsyncioPubsub
+
+pubsub = AsyncioPubsub()
+
 
 class Query(graphene.ObjectType):
     base = graphene.String()
 
+    async def resolve_base(root, info):
+        return 'Hello World!'
+
+
+class MutationExample(graphene.Mutation):
+    class Arguments:
+        input_text = graphene.String()
+
+    output_text = graphene.String()
+
+    async def mutate(self, info, input_text):
+        await pubsub.publish('BASE', input_text)
+        return MutationExample(output_text=input_text)
+
+
+class Mutations(graphene.ObjectType):
+    mutation_example = MutationExample.Field()
+
 
 class RandomType(graphene.ObjectType):
     seconds = graphene.Int()
@@ -15,6 +37,16 @@ class RandomType(graphene.ObjectType):
 class Subscription(graphene.ObjectType):
     count_seconds = graphene.Float(up_to=graphene.Int())
     random_int = graphene.Field(RandomType)
+    mutation_example = graphene.String()
+
+    async def resolve_mutation_example(root, info):
+        try:
+            sub_id, q = pubsub.subscribe_to_channel('BASE')
+            while True:
+                payload = await q.get()
+                yield payload
+        finally:
+            pubsub.unsubscribe('BASE', sub_id)
 
     async def resolve_count_seconds(root, info, up_to=5):
         for i in range(up_to):
@@ -31,4 +63,5 @@ async def resolve_random_int(root, info):
             i += 1
 
 
-schema = graphene.Schema(query=Query, subscription=Subscription)
+schema = graphene.Schema(query=Query, mutation=Mutations,
+                         subscription=Subscription)

examples/flask_gevent/app.py

@@ -20,7 +20,8 @@ def graphql_view():
 
 
 app.add_url_rule(
-    '/graphql', view_func=GraphQLView.as_view('graphql', schema=schema, graphiql=False))
+    '/graphql', view_func=GraphQLView.as_view('graphql', schema=schema,
+                                              graphiql=False))
 
 subscription_server = GeventSubscriptionServer(schema)
 app.app_protocol = lambda environ_path_info: 'graphql-ws'

examples/flask_gevent/schema.py

@@ -1,30 +1,58 @@
-import random
 import graphene
+import random
+
+from graphql_ws.pubsub import GeventRxPubsub
 from rx import Observable
 
+pubsub = GeventRxPubsub()
+
 
 class Query(graphene.ObjectType):
     base = graphene.String()
 
+    def resolve_base(root, info):
+        return 'Hello World!'
+
+
+class MutationExample(graphene.Mutation):
+    class Arguments:
+        input_text = graphene.String()
+
+    output_text = graphene.String()
+
+    def mutate(self, info, input_text):
+        pubsub.publish('BASE', input_text)
+        return MutationExample(output_text=input_text)
+
+
+class Mutations(graphene.ObjectType):
+    mutation_example = MutationExample.Field()
+
 
 class RandomType(graphene.ObjectType):
     seconds = graphene.Int()
     random_int = graphene.Int()
 
 
 class Subscription(graphene.ObjectType):
-
     count_seconds = graphene.Int(up_to=graphene.Int())
-
     random_int = graphene.Field(RandomType)
+    mutation_example = graphene.String()
+
+    def resolve_mutation_example(root, info):
+        # subscribe_to_channel method returns an observable
+        return pubsub.subscribe_to_channel('BASE')\
+                         .map(lambda i: "{0}".format(i))
 
     def resolve_count_seconds(root, info, up_to=5):
         return Observable.interval(1000)\
                          .map(lambda i: "{0}".format(i))\
                          .take_while(lambda i: int(i) <= up_to)
 
     def resolve_random_int(root, info):
-        return Observable.interval(1000).map(lambda i: RandomType(seconds=i, random_int=random.randint(0, 500)))
+        return Observable.interval(1000).map(
+            lambda i: RandomType(seconds=i, random_int=random.randint(0, 500)))
 
 
-schema = graphene.Schema(query=Query, subscription=Subscription)
+schema = graphene.Schema(query=Query, mutation=Mutations,
+                         subscription=Subscription)

examples/flask_gevent/template.py

@@ -117,9 +117,8 @@ def render_graphiql():
   </script>
 </body>
 </html>''').substitute(
-        GRAPHIQL_VERSION='0.11.7',
+        GRAPHIQL_VERSION='0.10.2',
         SUBSCRIPTIONS_TRANSPORT_VERSION='0.7.0',
         subscriptionsEndpoint='ws://localhost:5000/subscriptions',
-        # subscriptionsEndpoint='ws://localhost:5000/',
         endpointURL='/graphql',
     )