pgutkowski#38: Added support for suspendable property resolvers

src/main/kotlin/com/github/pgutkowski/kgraphql/schema/dsl/PropertyDSL.kt

@@ -40,6 +40,24 @@ class PropertyDSL<T : Any, R>(val name : String, block : PropertyDSL<T, R>.() ->
     fun <E, W, Q, A, S>resolver(function: (T, E, W, Q, A, S) -> R)
             = resolver(FunctionWrapper.on(function, true))
 
+    fun suspendResolver(function: suspend (T) -> R)
+            = resolver(FunctionWrapper.onSuspend(function, true))
+
+    fun <E>suspendResolver(function: suspend (T, E) -> R)
+            = resolver(FunctionWrapper.onSuspend(function, true))
+
+    fun <E, W>suspendResolver(function: suspend (T, E, W) -> R)
+            = resolver(FunctionWrapper.onSuspend(function, true))
+
+    fun <E, W, Q>suspendResolver(function: suspend (T, E, W, Q) -> R)
+            = resolver(FunctionWrapper.onSuspend(function, true))
+
+    fun <E, W, Q, A>suspendResolver(function: suspend (T, E, W, Q, A) -> R)
+            = resolver(FunctionWrapper.onSuspend(function, true))
+
+    fun <E, W, Q, A, S>suspendResolver(function: suspend (T, E, W, Q, A, S) -> R)
+            = resolver(FunctionWrapper.onSuspend(function, true))
+
     fun accessRule(rule: (T, Context) -> Exception?){
 
         val accessRuleAdapter: (T?, Context) -> Exception? = { parent, ctx ->
@@ -50,13 +68,13 @@ class PropertyDSL<T : Any, R>(val name : String, block : PropertyDSL<T, R>.() ->
     }
 
     fun toKQLProperty() = PropertyDef.Function<T, R>(
-            name = name,
-            resolver = functionWrapper,
-            description = description,
-            isDeprecated = isDeprecated,
-            deprecationReason = deprecationReason,
-            inputValues = inputValues,
-            accessRule = accessRuleBlock
+        name = name,
+        resolver = functionWrapper,
+        description = description,
+        isDeprecated = isDeprecated,
+        deprecationReason = deprecationReason,
+        inputValues = inputValues,
+        accessRule = accessRuleBlock
     )
 
     override fun addInputValues(inputValues: Collection<InputValueDef<*>>) {

src/main/kotlin/com/github/pgutkowski/kgraphql/schema/execution/ParallelRequestExecutor.kt

@@ -51,36 +51,14 @@ class ParallelRequestExecutor(val schema: DefaultSchema) : RequestExecutor, Coro
     override suspend fun suspendExecute(plan: ExecutionPlan, variables: VariablesJson, context: Context): String {
         val root = jsonNodeFactory.objectNode()
         val data = root.putObject("data")
-        val channel = Channel<Pair<Execution, JsonNode>>()
-        val jobs = plan
-                .map { execution ->
-                    launch(dispatcher) {
-                        try {
-                            val writeOperation = writeOperation(
-                                    ctx = ExecutionContext(Variables(schema, variables, execution.variables), context),
-                                    node = execution,
-                                    operation = execution.field as Field.Function<*, *>
-                            )
-                            channel.send(execution to writeOperation)
-                        } catch (e: Exception) {
-                            channel.close(e)
-                        }
-                    }
-                }
-                .toList()
 
-        //intermediate data structure necessary to preserve ordering
-        val resultMap = mutableMapOf<Execution, JsonNode>()
-        repeat(plan.size) {
-            try {
-                val (execution, jsonNode) = channel.receive()
-                resultMap.put(execution, jsonNode)
-            } catch (e: Exception) {
-                jobs.forEach { it.cancel() }
-                throw e
-            }
+        val resultMap = listToMapAsync(plan) {
+            writeOperation(
+                ctx = ExecutionContext(Variables(schema, variables, it.variables), context),
+                node = it,
+                operation = it.field as Field.Function<*, *>
+            )
         }
-        channel.close()
 
         for (operation in plan) {
             data.set(operation.aliasOrKey, resultMap[operation])
@@ -93,6 +71,34 @@ class ParallelRequestExecutor(val schema: DefaultSchema) : RequestExecutor, Coro
         suspendExecute(plan, variables, context)
     }
 
+    private suspend fun <T, R> listToMapAsync(data: Collection<T>, block: suspend (T) -> R): Map<T, R> {
+        val channel = Channel<Pair<T, R>>()
+        val jobs = data.map { item ->
+            launch(dispatcher) {
+                try {
+                    val res = block(item)
+                    channel.send(item to res)
+                } catch (e: Exception) {
+                    channel.close(e)
+                }
+            }
+        }
+
+        val resultMap = mutableMapOf<T, R>()
+        repeat(data.size) {
+            try {
+                val (item, result) = channel.receive()
+                resultMap[item] = result
+            } catch (e: Exception) {
+                jobs.forEach(Job::cancel)
+                throw e
+            }
+        }
+        channel.close()
+
+        return resultMap
+    }
+
     private suspend fun <T> writeOperation(ctx: ExecutionContext, node: Execution.Node, operation: FunctionWrapper<T>): JsonNode {
         node.field.checkAccess(null, ctx.requestContext)
         val operationResult: T? = operation.invoke(
@@ -134,9 +140,12 @@ class ParallelRequestExecutor(val schema: DefaultSchema) : RequestExecutor, Coro
             //check value, not returnType, because this method can be invoked with element value
             value is Collection<*> -> {
                 if (returnType.isList()) {
-                    val arrayNode = jsonNodeFactory.arrayNode(value.size)
-                    value.forEach { element -> arrayNode.add(createNode(ctx, element, node, returnType.unwrapList())) }
-                    arrayNode
+                    val valuesMap = listToMapAsync(value) {
+                        createNode(ctx, it, node, returnType.unwrapList())
+                    }
+                    value.fold(jsonNodeFactory.arrayNode(value.size)) { array, v ->
+                        array.add(valuesMap[v])
+                    }
                 } else {
                     throw ExecutionException("Invalid collection value for non collection property")
                 }

src/test/kotlin/com/github/pgutkowski/kgraphql/integration/ParallelExecutionTest.kt

@@ -1,39 +1,71 @@
 package com.github.pgutkowski.kgraphql.integration
 
 import com.github.pgutkowski.kgraphql.KGraphQL
-import com.github.pgutkowski.kgraphql.assertNoErrors
 import com.github.pgutkowski.kgraphql.extract
 import com.github.pgutkowski.kgraphql.deserialize
 import kotlinx.coroutines.delay
 import org.hamcrest.CoreMatchers
 import org.hamcrest.MatcherAssert
 import org.junit.Test
+import kotlin.random.Random
 
 class ParallelExecutionTest {
 
+    data class AType(val id: Int)
+
     val syncResolversSchema = KGraphQL.schema {
         repeat(1000) {
-            query("automated-${it}") {
+            query("automated-$it") {
                 resolver { ->
                     Thread.sleep(3)
-                    "${it}"
+                    "$it"
                 }
             }
         }
     }
 
     val suspendResolverSchema = KGraphQL.schema {
         repeat(1000) {
-            query("automated-${it}") {
+            query("automated-$it") {
                 suspendResolver { ->
                     delay(3)
-                    "${it}"
+                    "$it"
+                }
+            }
+        }
+    }
+
+    val suspendPropertySchema = KGraphQL.schema {
+        query("getAll") {
+            resolver { -> (0..999).map { AType(it) } }
+        }
+        type<AType> {
+            property<List<AType>>("children") {
+                suspendResolver { parent ->
+                    (0..50).map {
+                        delay(Random.nextLong(1, 100))
+                        AType((parent.id * 10) + it)
+                    }
                 }
             }
         }
     }
 
-    val query = "{ " + (0..999).map { "automated-${it}" }.joinToString(", ") + " }"
+    @Test
+    fun `Suspendable property resolvers`() {
+        val query = "{getAll{id,children{id}}}"
+        val map = deserialize(suspendPropertySchema.execute(query))
+
+        MatcherAssert.assertThat(map.extract<Int>("data/getAll[0]/id"), CoreMatchers.equalTo(0))
+        MatcherAssert.assertThat(map.extract<Int>("data/getAll[500]/id"), CoreMatchers.equalTo(500))
+        MatcherAssert.assertThat(map.extract<Int>("data/getAll[766]/id"), CoreMatchers.equalTo(766))
+
+        MatcherAssert.assertThat(map.extract<Int>("data/getAll[5]/children[5]/id"), CoreMatchers.equalTo(55))
+        MatcherAssert.assertThat(map.extract<Int>("data/getAll[75]/children[9]/id"), CoreMatchers.equalTo(759))
+        MatcherAssert.assertThat(map.extract<Int>("data/getAll[888]/children[50]/id"), CoreMatchers.equalTo(8930))
+    }
+
+    val query = "{ " + (0..999).map { "automated-$it" }.joinToString(", ") + " }"
 
     @Test
     fun `1000 synchronous resolvers sleeping with Thread sleep`(){