emit DDB_MAPPER business metric

aws-runtime/aws-http/api/aws-http.api

@@ -141,6 +141,7 @@ public final class aws/sdk/kotlin/runtime/http/interceptors/AddUserAgentMetadata
 }
 
 public final class aws/sdk/kotlin/runtime/http/interceptors/AwsBusinessMetric : java/lang/Enum, aws/smithy/kotlin/runtime/businessmetrics/BusinessMetric {
+	public static final field DDB_MAPPER Laws/sdk/kotlin/runtime/http/interceptors/AwsBusinessMetric;
 	public static final field S3_EXPRESS_BUCKET Laws/sdk/kotlin/runtime/http/interceptors/AwsBusinessMetric;
 	public static fun getEntries ()Lkotlin/enums/EnumEntries;
 	public fun getIdentifier ()Ljava/lang/String;

aws-runtime/aws-http/common/src/aws/sdk/kotlin/runtime/http/interceptors/BusinessMetricsInterceptor.kt

@@ -64,4 +64,5 @@ private fun formatMetrics(metrics: MutableSet<String>): String {
 @InternalApi
 public enum class AwsBusinessMetric(public override val identifier: String) : BusinessMetric {
     S3_EXPRESS_BUCKET("J"),
+    DDB_MAPPER("d"),
 }

hll/dynamodb-mapper/dynamodb-mapper/build.gradle.kts

@@ -26,6 +26,7 @@ kotlin {
     sourceSets {
         commonMain {
             dependencies {
+                implementation(project(":aws-runtime:aws-http"))
                 api(project(":services:dynamodb"))
                 api(project(":hll:hll-mapping-core"))
                 api(libs.kotlinx.coroutines.core)

hll/dynamodb-mapper/dynamodb-mapper/common/src/aws/sdk/kotlin/hll/dynamodbmapper/DynamoDbMapper.kt

@@ -112,4 +112,4 @@ public interface DynamoDbMapper {
 public fun DynamoDbMapper(
     client: DynamoDbClient,
     config: DynamoDbMapper.Config.Builder.() -> Unit = { },
-): DynamoDbMapper = DynamoDbMapperImpl(client, DynamoDbMapper.Config(config))
+): DynamoDbMapper = DynamoDbMapperImpl.wrapping(client, DynamoDbMapper.Config(config))

hll/dynamodb-mapper/dynamodb-mapper/common/src/aws/sdk/kotlin/hll/dynamodbmapper/internal/DynamoDbMapperImpl.kt

@@ -8,12 +8,27 @@ import aws.sdk.kotlin.hll.dynamodbmapper.DynamoDbMapper
 import aws.sdk.kotlin.hll.dynamodbmapper.items.ItemSchema
 import aws.sdk.kotlin.hll.dynamodbmapper.model.internal.tableImpl
 import aws.sdk.kotlin.hll.dynamodbmapper.pipeline.InterceptorAny
+import aws.sdk.kotlin.runtime.http.interceptors.AwsBusinessMetric
 import aws.sdk.kotlin.services.dynamodb.DynamoDbClient
+import aws.sdk.kotlin.services.dynamodb.withConfig
+import aws.smithy.kotlin.runtime.businessmetrics.emitBusinessMetric
+import aws.smithy.kotlin.runtime.client.RequestInterceptorContext
+import aws.smithy.kotlin.runtime.http.interceptors.HttpInterceptor
 
 internal data class DynamoDbMapperImpl(
     override val client: DynamoDbClient,
     override val config: DynamoDbMapper.Config,
 ) : DynamoDbMapper {
+    internal companion object {
+        /**
+         * Wraps a low-level [DynamoDbClient] to add additional features before instantiating a new
+         * [DynamoDbMapperImpl].
+         */
+        fun wrapping(client: DynamoDbClient, config: DynamoDbMapper.Config): DynamoDbMapperImpl {
+            val wrappedClient = client.withConfig { interceptors += DdbMapperMetricInterceptor }
+            return DynamoDbMapperImpl(wrappedClient, config)
+        }
+    }
     override fun <T, PK> getTable(name: String, schema: ItemSchema.PartitionKey<T, PK>) =
         tableImpl(this, name, schema)
 
@@ -35,3 +50,13 @@ internal class MapperConfigBuilderImpl : DynamoDbMapper.Config.Builder {
 
     override fun build() = MapperConfigImpl(interceptors.toList())
 }
+
+/**
+ * An interceptor that emits the DynamoDB Mapper business metric
+ */
+private object DdbMapperMetricInterceptor : HttpInterceptor {
+    override suspend fun modifyBeforeSerialization(context: RequestInterceptorContext<Any>): Any {
+        context.executionContext.emitBusinessMetric(AwsBusinessMetric.DDB_MAPPER)
+        return context.request
+    }
+}

hll/dynamodb-mapper/dynamodb-mapper/common/test/aws/sdk/kotlin/hll/dynamodbmapper/DynamoDbMapperTest.kt

@@ -0,0 +1,109 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package aws.sdk.kotlin.hll.dynamodbmapper
+
+import aws.sdk.kotlin.hll.dynamodbmapper.items.AttributeDescriptor
+import aws.sdk.kotlin.hll.dynamodbmapper.items.ItemSchema
+import aws.sdk.kotlin.hll.dynamodbmapper.items.KeySpec
+import aws.sdk.kotlin.hll.dynamodbmapper.items.SimpleItemConverter
+import aws.sdk.kotlin.hll.dynamodbmapper.operations.scanPaginated
+import aws.sdk.kotlin.hll.dynamodbmapper.testutils.DdbLocalTest
+import aws.sdk.kotlin.hll.dynamodbmapper.values.scalars.IntConverter
+import aws.sdk.kotlin.hll.dynamodbmapper.values.scalars.StringConverter
+import aws.sdk.kotlin.runtime.http.interceptors.AwsBusinessMetric
+import aws.sdk.kotlin.services.dynamodb.scan
+import aws.sdk.kotlin.services.dynamodb.withConfig
+import aws.smithy.kotlin.runtime.businessmetrics.BusinessMetric
+import aws.smithy.kotlin.runtime.businessmetrics.BusinessMetrics
+import aws.smithy.kotlin.runtime.client.ProtocolRequestInterceptorContext
+import aws.smithy.kotlin.runtime.collections.get
+import aws.smithy.kotlin.runtime.http.interceptors.HttpInterceptor
+import aws.smithy.kotlin.runtime.http.request.HttpRequest
+import kotlinx.coroutines.flow.collect
+import kotlinx.coroutines.test.runTest
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+class DynamoDbMapperTest : DdbLocalTest() {
+    companion object {
+        private const val TABLE_NAME = "dummy"
+
+        private data class DummyData(var foo: String = "", var bar: Int = 0)
+
+        private val dummyConverter = SimpleItemConverter(
+            ::DummyData,
+            { this },
+            AttributeDescriptor("foo", DummyData::foo, DummyData::foo::set, StringConverter),
+            AttributeDescriptor("bar", DummyData::bar, DummyData::bar::set, IntConverter),
+        )
+
+        private val dummySchema = ItemSchema(dummyConverter, KeySpec.String("foo"), KeySpec.Number("bar"))
+    }
+
+    @BeforeAll
+    fun setUp() = runTest {
+        createTable(TABLE_NAME, dummySchema)
+    }
+
+    @Test
+    fun testBusinessMetricEmission() = runTest {
+        val interceptor = MetricCapturingInterceptor()
+
+        val ddb = super.ddb.withConfig { interceptors += interceptor }
+        interceptor.assertEmpty()
+
+        // No metric for low-level client
+        ddb.scan { tableName = TABLE_NAME }
+        interceptor.assertMetric(AwsBusinessMetric.DDB_MAPPER, exists = false)
+        interceptor.reset()
+
+        // Metric for high-level client
+        val mapper = mapper(ddb)
+        val table = mapper.getTable(TABLE_NAME, dummySchema)
+        table.scanPaginated { }.collect()
+        interceptor.assertMetric(AwsBusinessMetric.DDB_MAPPER)
+        interceptor.reset()
+
+        // Still no metric for low-level client (i.e., LL wasn't modified by HL)
+        ddb.scan { tableName = TABLE_NAME }
+        interceptor.assertMetric(AwsBusinessMetric.DDB_MAPPER, exists = false)
+        interceptor.reset()
+
+        // Original client can be closed, mapper is unaffected
+        ddb.close()
+        table.scanPaginated { }.collect()
+        interceptor.assertMetric(AwsBusinessMetric.DDB_MAPPER)
+    }
+}
+
+private class MetricCapturingInterceptor : HttpInterceptor {
+    private val capturedMetrics = mutableSetOf<String>()
+
+    override fun readBeforeTransmit(context: ProtocolRequestInterceptorContext<Any, HttpRequest>) {
+        capturedMetrics += context.executionContext[BusinessMetrics]
+    }
+
+    fun assertMetric(metric: BusinessMetric, exists: Boolean = true) {
+        if (exists) {
+            assertTrue(
+                metric.identifier in capturedMetrics,
+                "Expected metrics to contain $metric. Actual values: $capturedMetrics",
+            )
+        } else {
+            assertFalse(
+                metric.identifier in capturedMetrics,
+                "Expected metrics *not* to contain $metric. Actual values: $capturedMetrics",
+            )
+        }
+    }
+
+    fun assertEmpty() {
+        assertTrue(capturedMetrics.isEmpty(), "Expected metrics to be empty. Actual values: $capturedMetrics")
+    }
+
+    fun reset() {
+        capturedMetrics.clear()
+    }
+}

hll/dynamodb-mapper/dynamodb-mapper/common/test/aws/sdk/kotlin/hll/dynamodbmapper/testutils/DdbLocalTest.kt

@@ -104,7 +104,10 @@ abstract class DdbLocalTest : AnnotationSpec() {
      * Returns a [DynamoDbMapper] instance utilizing the DynamoDB Local instance
      * @param config A function to set the configuration of the mapper before it's built
      */
-    fun mapper(config: DynamoDbMapper.Config.Builder.() -> Unit = { }) = DynamoDbMapper(ddb, config)
+    fun mapper(
+        ddb: DynamoDbClient? = null,
+        config: DynamoDbMapper.Config.Builder.() -> Unit = { },
+    ) = DynamoDbMapper(ddb ?: this.ddb, config)
 
     @AfterAll
     fun cleanUp() {