Resolver Tagging

[jhgg]

graphql-core supports "tagging" a resolver (via core.execution.middlewares.utils) as a way to signal special handling of the resolver in an ExecutionMiddleware.

The main example is that we have GeventExecutionMiddleware. By default, this middleware does nothing when processing resolvers. But when it is given a resolver that is tagged with (@run_in_greenlet) it will spawn a greenlet to execute the resolver, and allow the executor to continue to resolve other fields concurrently.

From the tests, here's a good example (not using Graphene):

@run_in_greenlet
def resolve_a(context, *_):
    gevent.sleep(3)
    return 'resolved a'

@run_in_greenlet
def resolve_b(context, *_):
    gevent.sleep(3)
    return 'resolved b'

Type = GraphQLObjectType('Type', {
    'a': GraphQLField(GraphQLString, resolver=resolver),
    'b': GraphQLField(GraphQLString, resolver=resolver_2)
})

executor = Executor(GraphQLSchema(Type), [GeventExecutionMiddleware()])

doc = 'query Example { a, b }'
result = executor.execute(doc)
assert result.data == {'a': 'resolved a', 'b': 'resolved b'}

In this example, if each function was not tagged with @run_in_greenlet, then the execution time would be 6 seconds, as they have to run serially. However, since they are tagged, the middleware will run them concurrently, executing the query in only 3 seconds.

[jhgg]

graphql-core also supports py3.5 asyncio, graphene's resolve functions should also support async/await in py35.

class Human(Character):
    pet = Field(Pet)

    async def resolve_pet(self, *args):
        pet = await queryPetFromSomewhereWithOwner(self.instance.id)
        return Pet(pet)

[jhgg]

I have more testing to do with 40b88bc. I'll have an answer for you tomorrow. Was just super busy today.