standardize coroutine context propagation in the execution (#1349)

📝 Description

Attempts to standardize how we can propagate the coroutine/reactor context created by the server when processing incoming requests to the data fetchers that would resolve the underlying fields.

`GraphQLContext` map was introduced in `graphql-java` 17 as means to standardize usage of GraphQL context (previously it could be any object). We can store the original GraphQL request context in the map and then use it from within the data fetchers.

This is a breaking change as we are changing signatures of `GraphQLContextFactory` and `FunctionDataFetcher`.

🔗 Related Issues

* #1336
* #1318
* #1300
* #1257

Author: dariuszkuc

examples/server/ktor-server/src/main/kotlin/com/expediagroup/graphql/examples/server/ktor/AuthorizedContext.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,25 +17,25 @@
 package com.expediagroup.graphql.examples.server.ktor
 
 import com.expediagroup.graphql.examples.server.ktor.schema.models.User
+import com.expediagroup.graphql.generator.execution.GraphQLContext
 import com.expediagroup.graphql.server.execution.GraphQLContextFactory
 import io.ktor.request.ApplicationRequest
 
 /**
  * Custom logic for how this example app should create its context given the [ApplicationRequest]
  */
-class KtorGraphQLContextFactory : GraphQLContextFactory<AuthorizedContext, ApplicationRequest> {
+class KtorGraphQLContextFactory : GraphQLContextFactory<GraphQLContext, ApplicationRequest> {
 
-    override suspend fun generateContext(request: ApplicationRequest): AuthorizedContext {
-        val loggedInUser = User(
+    override suspend fun generateContextMap(request: ApplicationRequest): Map<Any, Any> = mutableMapOf<Any, Any>(
+        "user" to User(
             email = "[email protected]",
             firstName = "Someone",
             lastName = "You Don't know",
             universityId = 4
         )
-
-        // Parse any headers from the Ktor request
-        val customHeader: String? = request.headers["my-custom-header"]
-
-        return AuthorizedContext(loggedInUser, customHeader = customHeader)
+    ).also { map ->
+        request.headers["my-custom-header"]?.let { customHeader ->
+            map["customHeader"] = customHeader
+        }
     }
 }

examples/server/ktor-server/src/main/kotlin/com/expediagroup/graphql/examples/server/ktor/KtorGraphQLContextFactory.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,32 +17,16 @@
 package com.expediagroup.graphql.examples.server.spring.context
 
 import com.expediagroup.graphql.server.execution.GraphQLContextFactory
-import com.expediagroup.graphql.server.spring.execution.SpringGraphQLContextFactory
-import com.expediagroup.graphql.server.spring.subscriptions.SpringSubscriptionGraphQLContextFactory
+import com.expediagroup.graphql.server.spring.execution.DefaultSpringGraphQLContextFactory
 import org.springframework.stereotype.Component
 import org.springframework.web.reactive.function.server.ServerRequest
-import org.springframework.web.reactive.socket.WebSocketSession
 
 /**
- * [GraphQLContextFactory] that generates [MyGraphQLContext] that will be available when processing GraphQL requests.
+ * [GraphQLContextFactory] that populates GraphQL context map that will be available when processing GraphQL requests.
  */
 @Component
-class MyGraphQLContextFactory : SpringGraphQLContextFactory<MyGraphQLContext>() {
-
-    override suspend fun generateContext(request: ServerRequest): MyGraphQLContext = MyGraphQLContext(
-        request = request,
-        myCustomValue = request.headers().firstHeader("MyHeader") ?: "defaultContext"
-    )
-}
-
-/**
- * [GraphQLContextFactory] that generates [MySubscriptionGraphQLContext] that will be available when processing subscription operations.
- */
-@Component
-class MySubscriptionGraphQLContextFactory : SpringSubscriptionGraphQLContextFactory<MySubscriptionGraphQLContext>() {
-
-    override suspend fun generateContext(request: WebSocketSession): MySubscriptionGraphQLContext = MySubscriptionGraphQLContext(
-        request = request,
-        auth = null
+class MyGraphQLContextFactory : DefaultSpringGraphQLContextFactory() {
+    override suspend fun generateContextMap(request: ServerRequest): Map<*, Any> = super.generateContextMap(request) + mapOf(
+        "myCustomValue" to (request.headers().firstHeader("MyHeader") ?: "defaultContext")
     )
 }

examples/server/spring-server/src/main/kotlin/com/expediagroup/graphql/examples/server/spring/context/MyGraphQLContext.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,8 +16,6 @@
 
 package com.expediagroup.graphql.examples.server.spring.execution
 
-import com.expediagroup.graphql.examples.server.spring.context.MySubscriptionGraphQLContext
-import com.expediagroup.graphql.generator.execution.GraphQLContext
 import com.expediagroup.graphql.server.spring.subscriptions.ApolloSubscriptionHooks
 import org.springframework.web.reactive.socket.WebSocketSession
 
@@ -26,14 +24,13 @@ import org.springframework.web.reactive.socket.WebSocketSession
  */
 class MySubscriptionHooks : ApolloSubscriptionHooks {
 
-    override fun onConnect(
+    override fun onConnectWithContext(
         connectionParams: Map<String, String>,
         session: WebSocketSession,
-        graphQLContext: GraphQLContext?
-    ): GraphQLContext? {
-        if (graphQLContext != null && graphQLContext is MySubscriptionGraphQLContext) {
-            graphQLContext.auth = connectionParams["Authorization"]
+        graphQLContext: Map<*, Any>
+    ): Map<*, Any> = mutableMapOf<Any, Any>().also { contextMap ->
+        connectionParams["Authorization"]?.let { authValue ->
+            contextMap["auth"] = authValue
         }
-        return graphQLContext
     }
 }

examples/server/spring-server/src/main/kotlin/com/expediagroup/graphql/examples/server/spring/context/MyGraphQLContextFactory.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,15 +16,15 @@
 
 package com.expediagroup.graphql.examples.server.spring.query
 
-import com.expediagroup.graphql.examples.server.spring.context.MyGraphQLContext
 import com.expediagroup.graphql.examples.server.spring.model.ContextualResponse
 import com.expediagroup.graphql.generator.annotations.GraphQLDescription
 import com.expediagroup.graphql.server.operations.Query
+import graphql.schema.DataFetchingEnvironment
 import org.springframework.stereotype.Component
 
 /**
- * Example usage of GraphQLContext. Since the argument [ContextualQuery.contextualQuery] implements
- * the GraphQLContext interface it will not appear in the schema and be populated at runtime.
+ * Example usage of GraphQLContext. Since `DataFetchingEnvironment` is passed as the argument
+ * of [ContextualQuery.contextualQuery], it will not appear in the schema and be populated at runtime.
  */
 @Component
 class ContextualQuery : Query {
@@ -33,6 +33,6 @@ class ContextualQuery : Query {
     fun contextualQuery(
         @GraphQLDescription("some value that will be returned to the user")
         value: Int,
-        context: MyGraphQLContext
-    ): ContextualResponse = ContextualResponse(value, context.myCustomValue)
+        env: DataFetchingEnvironment
+    ): ContextualResponse = ContextualResponse(value, env.graphQlContext.getOrDefault("myCustomValue", "defaultValue"))
 }

examples/server/spring-server/src/main/kotlin/com/expediagroup/graphql/examples/server/spring/execution/MySubscriptionHooks.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,6 @@
 
 package com.expediagroup.graphql.examples.server.spring.subscriptions
 
-import com.expediagroup.graphql.examples.server.spring.context.MySubscriptionGraphQLContext
 import com.expediagroup.graphql.generator.annotations.GraphQLDescription
 import com.expediagroup.graphql.server.operations.Subscription
 import graphql.GraphqlErrorException
@@ -79,8 +78,4 @@ class SimpleSubscription : Subscription {
 
         return flowOf(dfr, dfr).asPublisher()
     }
-
-    @GraphQLDescription("Returns a value from the subscription context")
-    fun subscriptionContext(myGraphQLContext: MySubscriptionGraphQLContext): Flux<String> =
-        Flux.just(myGraphQLContext.auth ?: "no-auth")
 }

examples/server/spring-server/src/main/kotlin/com/expediagroup/graphql/examples/server/spring/query/ContextualQuery.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,12 +20,13 @@ import graphql.GraphQLError
 import graphql.execution.DataFetcherResult
 import graphql.schema.DataFetcher
 import graphql.schema.DataFetchingEnvironment
-import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.async
 import kotlinx.coroutines.awaitAll
 import kotlinx.coroutines.coroutineScope
 import kotlinx.coroutines.future.future
 import java.util.concurrent.CompletableFuture
+import kotlin.coroutines.EmptyCoroutineContext
 
 private const val TYPENAME_FIELD = "__typename"
 private const val REPRESENTATIONS = "representations"
@@ -54,7 +55,8 @@ open class EntityResolver(resolvers: List<FederatedTypeResolver<*>>) : DataFetch
         val representations: List<Map<String, Any>> = env.getArgument(REPRESENTATIONS)
         val indexedBatchRequestsByType = representations.withIndex().groupBy { it.value[TYPENAME_FIELD].toString() }
 
-        return GlobalScope.future {
+        val scope = env.graphQlContext.getOrDefault(CoroutineScope::class, CoroutineScope(EmptyCoroutineContext))
+        return scope.future {
             val data = mutableListOf<Any?>()
             val errors = mutableListOf<GraphQLError>()
 

examples/server/spring-server/src/main/kotlin/com/expediagroup/graphql/examples/server/spring/subscriptions/SimpleSubscription.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -24,4 +24,5 @@ import com.expediagroup.graphql.generator.execution.GraphQLContext
  * request came from the Apollo Gateway. That means we need a special interface
  * for the federation context.
  */
+@Deprecated(message = "The generic context object is deprecated in favor of the context map", ReplaceWith("graphql.GraphQLContext"))
 interface FederatedGraphQLContext : GraphQLContext, HTTPRequestHeaders

generator/graphql-kotlin-federation/src/main/kotlin/com/expediagroup/graphql/generator/federation/execution/EntityResolver.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2021 Expedia, Inc
+ * Copyright 2022 Expedia, Inc
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,6 +20,7 @@ import com.expediagroup.graphql.generator.federation.data.BookResolver
 import com.expediagroup.graphql.generator.federation.data.UserResolver
 import com.expediagroup.graphql.generator.federation.data.queries.federated.Book
 import com.expediagroup.graphql.generator.federation.data.queries.federated.User
+import graphql.GraphQLContext
 import graphql.GraphQLError
 import graphql.schema.DataFetchingEnvironment
 import io.mockk.coEvery
@@ -38,6 +39,7 @@ class EntityQueryResolverTest {
         val representations = listOf(mapOf<String, Any>("__typename" to "User", "userId" to 123, "name" to "testName"))
         val env = mockk<DataFetchingEnvironment> {
             every { getArgument<Any>(any()) } returns representations
+            every { graphQlContext } returns GraphQLContext.newContext().build()
         }
 
         val result = resolver.get(env).get()
@@ -56,6 +58,7 @@ class EntityQueryResolverTest {
         val resolver = EntityResolver(listOf(mockBookResolver, mockUserResolver))
         val env = mockk<DataFetchingEnvironment> {
             every { getArgument<Any>(any()) } returns listOf(emptyMap<String, Any>())
+            every { graphQlContext } returns GraphQLContext.newContext().build()
         }
 
         val result = resolver.get(env).get()
@@ -69,6 +72,7 @@ class EntityQueryResolverTest {
         val representations = listOf(mapOf<String, Any>("__typename" to "User", "userId" to 123, "name" to "testName"))
         val env = mockk<DataFetchingEnvironment> {
             every { getArgument<Any>(any()) } returns representations
+            every { graphQlContext } returns GraphQLContext.newContext().build()
         }
 
         val result = resolver.get(env).get()
@@ -86,6 +90,7 @@ class EntityQueryResolverTest {
         val representations = listOf(mapOf<String, Any>("__typename" to "User", "userId" to 123, "name" to "testName"))
         val env: DataFetchingEnvironment = mockk {
             every { getArgument<Any>(any()) } returns representations
+            every { graphQlContext } returns GraphQLContext.newContext().build()
         }
 
         val result = resolver.get(env).get()
@@ -103,6 +108,7 @@ class EntityQueryResolverTest {
         val representations = listOf(user1.toRepresentation(), book.toRepresentation(), user2.toRepresentation())
         val env = mockk<DataFetchingEnvironment> {
             every { getArgument<Any>(any()) } returns representations
+            every { graphQlContext } returns GraphQLContext.newContext().build()
         }
 
         val spyUserResolver = spyk(UserResolver())
@@ -128,6 +134,7 @@ class EntityQueryResolverTest {
         val representations = listOf(user.toRepresentation(), book.toRepresentation())
         val env = mockk<DataFetchingEnvironment> {
             every { getArgument<Any>(any()) } returns representations
+            every { graphQlContext } returns GraphQLContext.newContext().build()
         }
 
         val spyUserResolver: UserResolver = spyk(UserResolver())
@@ -153,6 +160,7 @@ class EntityQueryResolverTest {
         val representations = listOf(user.toRepresentation(), user.toRepresentation())
         val env = mockk<DataFetchingEnvironment> {
             every { getArgument<Any>(any()) } returns representations
+            every { graphQlContext } returns GraphQLContext.newContext().build()
         }
 
         val mockUserResolver: UserResolver = mockk {