View Source Absinthe.Subscription (absinthe v1.7.5)
Real time updates via GraphQL
For a how to guide on getting started with Absinthe.Subscriptions in your phoenix
project see the Absinthe.Phoenix
package.
Define in your schema via Absinthe.Schema.subscription/2
basic-usage
Basic Usage
performance-characteristics
Performance Characteristics
There are a couple of limitations to the beta release of subscriptions that are worth keeping in mind if you want to use this in production:
By design, all subscription docs triggered by a mutation are run inside the mutation process as a form of back pressure.
At the moment however database batching does not happen across the set of subscription docs. Thus if you have a lot of subscription docs and they each do a lot of extra DB lookups you're going to delay incoming mutation responses by however long it takes to do all that work.
Before the final version of 1.4.0 we want
- Batching across subscriptions
- More user control over back pressure / async balance.
Link to this section Summary
Functions
Build a child specification for subscriptions.
Publish a mutation
Add Absinthe.Subscription to your process tree.
Link to this section Types
@type opt() :: {:pubsub, atom()} | {:compress_registry?, boolean()} | {:pool_size, pos_integer()}
Link to this section Functions
@spec child_spec(atom() | [opt()]) :: Supervisor.child_spec()
Build a child specification for subscriptions.
In order to use supscriptions in your application, you must add
Absinthe.Subscription
to your supervision tree after your endpoint.
See guides/subscriptions.md
for more information on how to get up and
running with subscriptions.
options
Options
:pubsub
- (Required) ThePhoenix.Pubsub
that should be used to publish subscriptions. Typically this will be yourPhoenix.Endpoint
.:compress_registry?
- (Optional - defaulttrue
) A boolean controlling whether the Registry used to keep track of subscriptions will should be compressed or not.:pool_size
- (Optional - defaultSystem.schedulers() * 2
) An integer specifying the number ofAbsinthe.Subscription.Proxy
processes to start.
@spec publish( Absinthe.Subscription.Pubsub.t(), term(), Absinthe.Resolution.t() | [subscription_field_spec()] ) :: :ok
Publish a mutation
This function is generally used when trying to publish to one or more subscription fields "out of band" from any particular mutation.
examples
Examples
Note: As with all subscription examples if you're using Absinthe.Phoenix pubsub
will be MyAppWeb.Endpoint
.
Absinthe.Subscription.publish(pubsub, user, [new_users: user.account_id])
# publish to two subscription fields
Absinthe.Subscription.publish(pubsub, user, [
new_users: user.account_id,
other_user_subscription_field: user.id,
])
@spec start_link(atom() | [opt()]) :: Supervisor.on_start()
Add Absinthe.Subscription to your process tree.