make subscriptions opt_in

config/config.exs

@@ -9,6 +9,8 @@ config :logger, level: :warning
 config :ash, :pub_sub, debug?: true
 config :logger, level: :info
 
+config :ash_graphql, :subscriptions, true
+
 if Mix.env() == :dev do
   config :git_ops,
     mix_project: AshGraphql.MixProject,

lib/resource/resource.ex

@@ -459,7 +459,8 @@ defmodule AshGraphql.Resource do
   @verifiers [
     AshGraphql.Resource.Verifiers.VerifyQueryMetadata,
     AshGraphql.Resource.Verifiers.RequirePkeyDelimiter,
-    AshGraphql.Resource.Verifiers.VerifyPaginateRelationshipWith
+    AshGraphql.Resource.Verifiers.VerifyPaginateRelationshipWith,
+    AshGraphql.Resource.Verifiers.VerifySubscriptionOptIn
   ]
 
   @sections [@graphql]

lib/resource/verifiers/verify_subscription_opt_in.ex

@@ -0,0 +1,23 @@
+defmodule AshGraphql.Resource.Verifiers.VerifySubscriptionOptIn do
+  # Checks if the users has opted into using subscriptions
+  @moduledoc false
+
+  use Spark.Dsl.Verifier
+  alias Spark.Dsl.Transformer
+
+  def verify(dsl) do
+    has_subscriptions =
+      not (dsl
+           |> AshGraphql.Resource.Info.subscriptions()
+           |> Enum.empty?())
+
+    if has_subscriptions && not Application.get_env(:ash_graphql, :subscriptions, false) do
+      raise Spark.Error.DslError,
+        module: Transformer.get_persisted(dsl, :module),
+        message: "Subscriptions are in beta and must be enabled in the config",
+        path: [:graphql, :subscriptions]
+    end
+
+    :ok
+  end
+end