feat: OkHttpEngine BYOC (#1437)

Author: lauzadis

.changes/4d3a104a-3225-4dcb-be05-f5155d320952.json

@@ -0,0 +1,8 @@
+{
+    "id": "4d3a104a-3225-4dcb-be05-f5155d320952",
+    "type": "feature",
+    "description": "Allow configuring a custom OkHttpClient in OkHttpEngine",
+    "issues": [
+        "https://github.com/aws/aws-sdk-kotlin/issues/1707"
+    ]
+}

runtime/build.gradle.kts

@@ -143,8 +143,6 @@ subprojects {
     }
 }
 
-// configureIosSimulatorTasks()
-
 val excludeFromDocumentation = listOf(
     ":runtime:testing",
     ":runtime:smithy-test",

runtime/protocol/http-client-engines/http-client-engine-okhttp/api/http-client-engine-okhttp.api

@@ -53,6 +53,8 @@ public final class aws/smithy/kotlin/runtime/http/engine/okhttp/OkHttpEngine : a
 	public static final field Companion Laws/smithy/kotlin/runtime/http/engine/okhttp/OkHttpEngine$Companion;
 	public fun <init> ()V
 	public fun <init> (Laws/smithy/kotlin/runtime/http/engine/okhttp/OkHttpEngineConfig;)V
+	public synthetic fun <init> (Laws/smithy/kotlin/runtime/http/engine/okhttp/OkHttpEngineConfig;Lokhttp3/OkHttpClient;Lkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun <init> (Lokhttp3/OkHttpClient;)V
 	public synthetic fun getConfig ()Laws/smithy/kotlin/runtime/http/engine/HttpClientEngineConfig;
 	public fun getConfig ()Laws/smithy/kotlin/runtime/http/engine/okhttp/OkHttpEngineConfig;
 	public fun roundTrip (Laws/smithy/kotlin/runtime/operation/ExecutionContext;Laws/smithy/kotlin/runtime/http/request/HttpRequest;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;

runtime/protocol/http-client-engines/http-client-engine-okhttp/jvm/src/aws/smithy/kotlin/runtime/http/engine/okhttp/OkHttpEngine.kt

@@ -9,6 +9,7 @@ import aws.smithy.kotlin.runtime.InternalApi
 import aws.smithy.kotlin.runtime.http.HttpCall
 import aws.smithy.kotlin.runtime.http.config.EngineFactory
 import aws.smithy.kotlin.runtime.http.engine.AlpnId
+import aws.smithy.kotlin.runtime.http.engine.HttpClientEngine
 import aws.smithy.kotlin.runtime.http.engine.HttpClientEngineBase
 import aws.smithy.kotlin.runtime.http.engine.TlsContext
 import aws.smithy.kotlin.runtime.http.engine.callContext
@@ -34,18 +35,23 @@ import okhttp3.TlsVersion as OkHttpTlsVersion
 /**
  * [aws.smithy.kotlin.runtime.http.engine.HttpClientEngine] based on OkHttp.
  */
-public class OkHttpEngine(
+public class OkHttpEngine private constructor(
     override val config: OkHttpEngineConfig,
+    private val userProvidedClient: OkHttpClient?,
 ) : HttpClientEngineBase("OkHttp") {
-    public constructor() : this(OkHttpEngineConfig.Default)
+    public constructor() : this(OkHttpEngineConfig.Default, null)
+
+    public constructor(config: OkHttpEngineConfig) : this(config, null)
+
+    public constructor(client: OkHttpClient) : this(OkHttpEngineConfig.Default, client)
 
     public companion object : EngineFactory<OkHttpEngineConfig.Builder, OkHttpEngine> {
         /**
          * Initializes a new [OkHttpEngine] via a DSL builder block
          * @param block A receiver lambda which sets the properties of the config to be built
          */
         public operator fun invoke(block: OkHttpEngineConfig.Builder.() -> Unit): OkHttpEngine =
-            OkHttpEngine(OkHttpEngineConfig(block))
+            OkHttpEngine(OkHttpEngineConfig(block), null)
 
         override val engineConstructor: (OkHttpEngineConfig.Builder.() -> Unit) -> OkHttpEngine = ::invoke
     }
@@ -57,7 +63,10 @@ public class OkHttpEngine(
         }
 
     private val metrics = HttpClientMetrics(TELEMETRY_SCOPE, config.telemetryProvider)
-    private val client = config.buildClient(metrics, connectionMonitoringListener)
+    private val client: OkHttpClient by lazy {
+        userProvidedClient?.withMetrics(metrics, config)
+            ?: config.buildClient(metrics, connectionMonitoringListener)
+    }
 
     @OptIn(ExperimentalCoroutinesApi::class)
     override suspend fun roundTrip(context: ExecutionContext, request: HttpRequest): HttpCall {
@@ -85,9 +94,11 @@ public class OkHttpEngine(
 
     override fun shutdown() {
         connectionMonitoringListener?.closeIfCloseable()
-        client.connectionPool.evictAll()
-        client.dispatcher.executorService.shutdown()
         metrics.close()
+        if (userProvidedClient == null) {
+            client.connectionPool.evictAll()
+            client.dispatcher.executorService.shutdown()
+        }
     }
 }
 
@@ -170,6 +181,18 @@ public fun OkHttpEngineConfig.buildClient(
     }.build()
 }
 
+// Configure a user-provided client to collect SDK metrics
+private fun OkHttpClient.withMetrics(metrics: HttpClientMetrics, config: OkHttpEngineConfig) = newBuilder().apply {
+    eventListenerFactory { call ->
+        EventListenerChain(
+            listOf(
+                HttpEngineEventListener(connectionPool, config.hostResolver, dispatcher, metrics, call),
+            ),
+        )
+    }
+    addInterceptor(MetricsInterceptor)
+}.build()
+
 private fun tlsConnectionSpec(tlsContext: TlsContext, cipherSuites: List<String>?): ConnectionSpec {
     val minVersion = tlsContext.minVersion ?: TlsVersion.TLS_1_2
     val okHttpTlsVersions = SdkTlsVersion

runtime/protocol/http-client-engines/http-client-engine-okhttp/jvm/test/aws/smithy/kotlin/runtime/http/engine/okhttp/OkHttpEngineConfigTest.kt

@@ -0,0 +1,43 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package aws.smithy.kotlin.runtime.http.engine.okhttp
+
+import aws.smithy.kotlin.runtime.content.ByteStream
+import aws.smithy.kotlin.runtime.http.Headers
+import aws.smithy.kotlin.runtime.http.HttpException
+import aws.smithy.kotlin.runtime.http.HttpMethod
+import aws.smithy.kotlin.runtime.http.SdkHttpClient
+import aws.smithy.kotlin.runtime.http.request.HttpRequest
+import aws.smithy.kotlin.runtime.http.toHttpBody
+import aws.smithy.kotlin.runtime.net.url.Url
+import kotlinx.coroutines.test.runTest
+import okhttp3.OkHttpClient
+import java.io.IOException
+import kotlin.test.Test
+import kotlin.test.assertFailsWith
+import kotlin.test.assertTrue
+
+class OkHttpEngineConfigTest {
+    @Test
+    fun testUserClient() = runTest {
+        val userClient = OkHttpClient.Builder().apply {
+            addInterceptor { throw DummyOkHttpClientException() }
+        }.build()
+
+        val engine = OkHttpEngine(userClient)
+        val sdkClient = SdkHttpClient(engine)
+
+        val data = "a".repeat(100)
+        val url = Url.parse("https://aws.amazon.com")
+        val request = HttpRequest(HttpMethod.POST, url, Headers.Empty, ByteStream.fromString(data).toHttpBody())
+
+        val ex = assertFailsWith<HttpException> {
+            sdkClient.call(request)
+        }
+        assertTrue(ex.cause is DummyOkHttpClientException)
+    }
+
+    private class DummyOkHttpClientException : IOException("Custom OkHttpClient interceptor was called")
+}