feat: add domain-level pubsub configuration for subscriptions (#341)

Author: barnabasJ

documentation/dsls/DSL-AshGraphql.Domain.md

@@ -483,6 +483,8 @@ Subscriptions to expose for the resource.
 ### Examples
 ```
 subscription do
+  pubsub MyApp.PubSub
+
   subscribe Post, :post_created do
     action_types(:create)
   end
@@ -493,6 +495,14 @@ end
 
 
 
+### Options
+
+| Name | Type | Default | Docs |
+|------|------|---------|------|
+| [`pubsub`](#graphql-subscriptions-pubsub){: #graphql-subscriptions-pubsub } | `module` |  | The pubsub module to use for subscriptions in this domain. Resources can override this by specifying their own pubsub. |
+
+
+
 ### graphql.subscriptions.subscribe
 ```elixir
 subscribe resource, name

documentation/dsls/DSL-AshGraphql.Resource.md

@@ -520,7 +520,7 @@ end
 
 | Name | Type | Default | Docs |
 |------|------|---------|------|
-| [`pubsub`](#graphql-subscriptions-pubsub){: #graphql-subscriptions-pubsub .spark-required} | `module` |  | The pubsub module to use for the subscription |
+| [`pubsub`](#graphql-subscriptions-pubsub){: #graphql-subscriptions-pubsub } | `module` |  | The pubsub module to use for the subscription. If not specified, will use the domain's pubsub configuration. |
 
 
 

lib/domain/domain.ex

@@ -65,12 +65,21 @@ defmodule AshGraphql.Domain do
     examples: [
       """
       subscription do
+        pubsub MyApp.PubSub
+
         subscribe Post, :post_created do
           action_types(:create)
         end
       end
       """
     ],
+    schema: [
+      pubsub: [
+        type: :module,
+        doc:
+          "The pubsub module to use for subscriptions in this domain. Resources can override this by specifying their own pubsub."
+      ]
+    ],
     entities:
       Enum.map(
         AshGraphql.Resource.subscriptions(),
@@ -152,7 +161,8 @@ defmodule AshGraphql.Domain do
       AshGraphql.Domain.Transformers.ValidateCompatibleNames
     ],
     verifiers: [
-      AshGraphql.Resource.Verifiers.VerifyDomainQueryMetadata
+      AshGraphql.Resource.Verifiers.VerifyDomainQueryMetadata,
+      AshGraphql.Domain.Verifiers.VerifySubscriptionPubsub
     ]
 
   if Code.ensure_loaded?(Igniter) do

lib/domain/info.ex

@@ -46,6 +46,11 @@ defmodule AshGraphql.Domain.Info do
     Extension.get_entities(resource, [:graphql, :subscriptions]) || []
   end
 
+  @doc "The pubsub module configured for subscriptions in this domain"
+  def subscription_pubsub(domain) do
+    Extension.get_opt(domain, [:graphql, :subscriptions], :pubsub)
+  end
+
   @doc "Whether or not to render raised errors in the GraphQL response"
   def show_raised_errors?(domain) do
     Extension.get_opt(domain, [:graphql], :show_raised_errors?, false, true)

lib/domain/verifiers/verify_subscription_pubsub.ex

@@ -0,0 +1,65 @@
+defmodule AshGraphql.Domain.Verifiers.VerifySubscriptionPubsub do
+  @moduledoc """
+  Verifies that pubsub is properly configured for subscriptions at the domain level.
+
+  This verifier ensures that:
+  - If a domain has subscriptions, it either has pubsub configured or all its resources with subscriptions have pubsub configured
+  - Resources with subscriptions have pubsub available either at the resource level or domain level
+  """
+
+  use Spark.Dsl.Verifier
+
+  def verify(dsl) do
+    domain_subscriptions = AshGraphql.Domain.Info.subscriptions(dsl)
+    domain_pubsub = AshGraphql.Domain.Info.subscription_pubsub(dsl)
+
+    if is_nil(domain_pubsub) do
+      already_checked =
+        if domain_subscriptions != [] do
+          domain_subscriptions
+          |> Enum.map(fn subscription ->
+            resource = subscription.resource
+
+            Code.ensure_loaded!(resource)
+
+            resource_pubsub = AshGraphql.Resource.Info.subscription_pubsub(resource)
+
+            unless resource_pubsub do
+              raise Spark.Error.DslError,
+                module: Spark.Dsl.Transformer.get_persisted(resource.spark_dsl_config(), :module),
+                message:
+                  "Domain subscription for #{inspect(resource)} requires pubsub to be configured either at the domain level or on the resource #{inspect(resource)} itself.",
+                path: [:graphql, :subscriptions, subscription.name]
+            end
+
+            resource
+          end)
+        else
+          []
+        end
+
+      dsl
+      |> Ash.Domain.Info.resources()
+      |> Kernel.--(already_checked)
+      |> Enum.each(fn resource ->
+        Code.ensure_loaded!(resource)
+
+        resource_subscriptions = AshGraphql.Resource.Info.subscriptions(resource, dsl)
+
+        if resource_subscriptions != [] do
+          resource_pubsub = AshGraphql.Resource.Info.subscription_pubsub(resource)
+
+          unless resource_pubsub do
+            raise Spark.Error.DslError,
+              module: Spark.Dsl.Transformer.get_persisted(resource.spark_dsl_config(), :module),
+              message:
+                "Resource #{inspect(resource)} has subscriptions but no pubsub module configured. A pubsub module must be specified either at the resource level (in the subscriptions section) or at the domain level (in the domain's graphql subscriptions section).",
+              path: [:graphql, :subscriptions, :pubsub]
+          end
+        end
+      end)
+    end
+
+    :ok
+  end
+end

lib/resource/info.ex

@@ -52,8 +52,16 @@ defmodule AshGraphql.Resource.Info do
   end
 
   @doc "The pubsub module used for subscriptions"
-  def subscription_pubsub(resource) do
-    Extension.get_opt(resource, [:graphql, :subscriptions], :pubsub)
+  def subscription_pubsub(resource, domain_or_domains \\ []) do
+    case Extension.get_opt(resource, [:graphql, :subscriptions], :pubsub) do
+      nil ->
+        domain_or_domains
+        |> List.wrap()
+        |> Enum.find_value(&AshGraphql.Domain.Info.subscription_pubsub/1)
+
+      pubsub_module ->
+        pubsub_module
+    end
   end
 
   @doc "Wether or not to encode the primary key as a single `id` field when reading and getting"

lib/resource/resource.ex

@@ -308,8 +308,8 @@ defmodule AshGraphql.Resource do
     schema: [
       pubsub: [
         type: :module,
-        required: true,
-        doc: "The pubsub module to use for the subscription"
+        doc:
+          "The pubsub module to use for the subscription. If not specified, will use the domain's pubsub configuration."
       ]
     ],
     describe: """

lib/subscription/notifier.ex

@@ -9,7 +9,7 @@ defmodule AshGraphql.Subscription.Notifier do
 
   @impl Ash.Notifier
   def notify(%Ash.Notifier.Notification{} = notification) do
-    pub_sub = Info.subscription_pubsub(notification.resource)
+    pub_sub = Info.subscription_pubsub(notification.resource, notification.domain)
 
     for subscription <-
           AshGraphql.Resource.Info.subscriptions(notification.resource, notification.domain) do

test/domain_pubsub_validation_test.exs

@@ -0,0 +1,177 @@
+defmodule AshGraphql.DomainPubsubValidationTest do
+  use ExUnit.Case, async: false
+
+  describe "domain pubsub validation during compilation" do
+    test "raises error when resource has subscriptions but no pubsub and domain has no pubsub" do
+      assert_raise Spark.Error.DslError, fn ->
+        defmodule TestResourceWithoutPubsub do
+          use Ash.Resource,
+            domain: TestDomainWithoutPubsub,
+            extensions: [AshGraphql.Resource]
+
+          graphql do
+            type :test_resource_without_pubsub
+
+            subscriptions do
+              subscribe(:test_subscription) do
+                action_types([:create])
+              end
+            end
+          end
+
+          actions do
+            default_accept(:*)
+            defaults([:create])
+          end
+
+          attributes do
+            uuid_primary_key(:id)
+          end
+        end
+
+        defmodule TestDomainWithoutPubsub do
+          use Ash.Domain, extensions: [AshGraphql.Domain]
+
+          graphql do
+            subscriptions do
+            end
+          end
+
+          resources do
+            resource(TestResourceWithoutPubsub)
+          end
+        end
+      end
+    end
+
+    test "raises error when domain has subscriptions but no pubsub and resource has no pubsub" do
+      assert_raise Spark.Error.DslError, fn ->
+        defmodule TestResourceWithoutPubsub2 do
+          use Ash.Resource,
+            domain: TestDomainWithoutPubsub2,
+            extensions: [AshGraphql.Resource]
+
+          graphql do
+            type :test_resource_without_pubsub2
+
+            subscriptions do
+              subscribe(:test_subscription) do
+                action_types([:create])
+              end
+            end
+          end
+
+          actions do
+            default_accept(:*)
+            defaults([:create])
+          end
+
+          attributes do
+            uuid_primary_key(:id)
+          end
+        end
+
+        defmodule TestDomainWithoutPubsub2 do
+          use Ash.Domain, extensions: [AshGraphql.Domain]
+
+          graphql do
+            subscriptions do
+              subscribe TestResourceWithoutPubsub2, :test_subscription do
+                action_types([:create])
+              end
+            end
+          end
+
+          resources do
+            resource(TestResourceWithoutPubsub2)
+          end
+        end
+      end
+    end
+
+    test "succeeds when domain has pubsub and resource has no pubsub" do
+      defmodule TestResourceWithoutPubsub3 do
+        use Ash.Resource, domain: TestDomainWithPubsub3, extensions: [AshGraphql.Resource]
+
+        graphql do
+          type :test_resource_without_pubsub3
+
+          subscriptions do
+            subscribe(:test_subscription) do
+              action_types([:create])
+            end
+          end
+        end
+
+        actions do
+          default_accept(:*)
+          defaults([:create])
+        end
+
+        attributes do
+          uuid_primary_key(:id)
+        end
+      end
+
+      defmodule TestDomainWithPubsub3 do
+        use Ash.Domain, extensions: [AshGraphql.Domain]
+
+        graphql do
+          subscriptions do
+            pubsub AshGraphql.Test.PubSub
+          end
+        end
+
+        resources do
+          resource(TestResourceWithoutPubsub3)
+        end
+      end
+
+      assert TestDomainWithPubsub3
+      assert TestResourceWithoutPubsub3
+    end
+
+    test "succeeds when resource has pubsub and domain has no pubsub" do
+      defmodule TestResourceWithPubsub4 do
+        use Ash.Resource, domain: TestDomainWithoutPubsub4, extensions: [AshGraphql.Resource]
+
+        graphql do
+          type :test_resource_with_pubsub4
+
+          subscriptions do
+            pubsub AshGraphql.Test.PubSub
+
+            subscribe(:test_subscription) do
+              action_types([:create])
+            end
+          end
+        end
+
+        actions do
+          default_accept(:*)
+          defaults([:create])
+        end
+
+        attributes do
+          uuid_primary_key(:id)
+        end
+      end
+
+      defmodule TestDomainWithoutPubsub4 do
+        use Ash.Domain, extensions: [AshGraphql.Domain]
+
+        graphql do
+          subscriptions do
+          end
+        end
+
+        resources do
+          resource(TestResourceWithPubsub4)
+        end
+      end
+
+      assert TestDomainWithoutPubsub4
+      assert TestResourceWithPubsub4
+    end
+  end
+end