Add apache HTTP request stats

http-client-spi/pom.xml

@@ -50,6 +50,11 @@
             <artifactId>utils</artifactId>
             <version>${awsjavasdk.version}</version>
         </dependency>
+        <dependency>
+            <groupId>software.amazon.awssdk</groupId>
+            <artifactId>metrics-spi</artifactId>
+            <version>${awsjavasdk.version}</version>
+        </dependency>
         <dependency>
             <groupId>org.reactivestreams</groupId>
             <artifactId>reactive-streams</artifactId>

http-client-spi/src/main/java/software/amazon/awssdk/http/HttpExecuteRequest.java

@@ -17,6 +17,7 @@
 
 import java.util.Optional;
 import software.amazon.awssdk.annotations.SdkPublicApi;
+import software.amazon.awssdk.metrics.MetricCollector;
 
 /**
  * Request object containing the parameters necessary to make a synchronous HTTP request.
@@ -28,10 +29,12 @@ public final class HttpExecuteRequest {
 
     private final SdkHttpRequest request;
     private final Optional<ContentStreamProvider> contentStreamProvider;
+    private final MetricCollector metricCollector;
 
     private HttpExecuteRequest(BuilderImpl builder) {
         this.request = builder.request;
         this.contentStreamProvider = builder.contentStreamProvider;
+        this.metricCollector = builder.metricCollector;
     }
 
     /**
@@ -48,6 +51,13 @@ public Optional<ContentStreamProvider> contentStreamProvider() {
         return contentStreamProvider;
     }
 
+    /**
+     * @return The {@link MetricCollector}.
+     */
+    public Optional<MetricCollector> metricCollector() {
+        return Optional.ofNullable(metricCollector);
+    }
+
     public static Builder builder() {
         return new BuilderImpl();
     }
@@ -68,12 +78,22 @@ public interface Builder {
          */
         Builder contentStreamProvider(ContentStreamProvider contentStreamProvider);
 
+        /**
+         * Set the {@link MetricCollector} to be used by the HTTP client to
+         * report metrics collected for this request.
+         *
+         * @param metricCollector The metric collector.
+         * @return This bilder for method chaining.
+         */
+        Builder metricCollector(MetricCollector metricCollector);
+
         HttpExecuteRequest build();
     }
 
     private static class BuilderImpl implements Builder {
         private SdkHttpRequest request;
         private Optional<ContentStreamProvider> contentStreamProvider = Optional.empty();
+        private MetricCollector metricCollector;
 
         @Override
         public Builder request(SdkHttpRequest request) {
@@ -87,6 +107,12 @@ public Builder contentStreamProvider(ContentStreamProvider contentStreamProvider
             return this;
         }
 
+        @Override
+        public Builder metricCollector(MetricCollector metricCollector) {
+            this.metricCollector = metricCollector;
+            return this;
+        }
+
         @Override
         public HttpExecuteRequest build() {
             return new HttpExecuteRequest(this);

http-client-spi/src/main/java/software/amazon/awssdk/http/HttpMetric.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package software.amazon.awssdk.http;
+
+import software.amazon.awssdk.annotations.SdkPublicApi;
+import software.amazon.awssdk.metrics.MetricCategory;
+import software.amazon.awssdk.metrics.SdkMetric;
+
+/**
+ * Metrics collected by HTTP clients.
+ */
+@SdkPublicApi
+public final class HttpMetric {
+    /**
+     * The name of the HTTP client.
+     */
+    public static final SdkMetric<String> HTTP_CLIENT_NAME = metric("HttpClientName", String.class);
+
+    /**
+     * The maximum number of connections that will be pooled by the HTTP client.
+     */
+    public static final SdkMetric<Integer> MAX_CONNECTIONS = metric("MaxConnections", Integer.class);
+
+    /**
+     * The number of idle connections in the connection pool that are ready to serve a request.
+     */
+    public static final SdkMetric<Integer> AVAILABLE_CONNECTIONS = metric("AvailableConnections", Integer.class);
+
+    /**
+     * The number of connections from the connection pool that are busy serving requests.
+     */
+    public static final SdkMetric<Integer> LEASED_CONNECTIONS = metric("LeasedConnections", Integer.class);
+
+    /**
+     * The number of requests awaiting a free connection from the pool.
+     */
+    public static final SdkMetric<Integer> PENDING_CONNECTION_ACQUIRES = metric("PendingConnectionAcquires", Integer.class);
+
+    private HttpMetric() {
+    }
+
+    private static <T> SdkMetric<T> metric(String name, Class<T> clzz) {
+        return SdkMetric.create(name, clzz, MetricCategory.DEFAULT, MetricCategory.HTTP_CLIENT);
+    }
+}

http-clients/apache-client/pom.xml

@@ -33,6 +33,11 @@
             <artifactId>http-client-spi</artifactId>
             <version>${awsjavasdk.version}</version>
         </dependency>
+        <dependency>
+            <groupId>software.amazon.awssdk</groupId>
+            <artifactId>metrics-spi</artifactId>
+            <version>${awsjavasdk.version}</version>
+        </dependency>
         <dependency>
             <groupId>software.amazon.awssdk</groupId>
             <artifactId>utils</artifactId>

http-clients/apache-client/src/main/java/software/amazon/awssdk/http/apache/ApacheHttpClient.java

@@ -18,6 +18,11 @@
 import static java.util.stream.Collectors.groupingBy;
 import static java.util.stream.Collectors.mapping;
 import static java.util.stream.Collectors.toList;
+import static software.amazon.awssdk.http.HttpMetric.AVAILABLE_CONNECTIONS;
+import static software.amazon.awssdk.http.HttpMetric.HTTP_CLIENT_NAME;
+import static software.amazon.awssdk.http.HttpMetric.LEASED_CONNECTIONS;
+import static software.amazon.awssdk.http.HttpMetric.MAX_CONNECTIONS;
+import static software.amazon.awssdk.http.HttpMetric.PENDING_CONNECTION_ACQUIRES;
 import static software.amazon.awssdk.utils.NumericUtils.saturatedCast;
 
 import java.io.IOException;
@@ -57,6 +62,7 @@
 import org.apache.http.impl.client.HttpClients;
 import org.apache.http.impl.conn.DefaultSchemePortResolver;
 import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
+import org.apache.http.pool.PoolStats;
 import org.apache.http.protocol.HttpRequestExecutor;
 import software.amazon.awssdk.annotations.SdkPublicApi;
 import software.amazon.awssdk.annotations.SdkTestInternalApi;
@@ -72,6 +78,7 @@
 import software.amazon.awssdk.http.TlsTrustManagersProvider;
 import software.amazon.awssdk.http.apache.internal.ApacheHttpRequestConfig;
 import software.amazon.awssdk.http.apache.internal.DefaultConfiguration;
+import software.amazon.awssdk.http.apache.internal.NoOpMetricCollector;
 import software.amazon.awssdk.http.apache.internal.SdkProxyRoutePlanner;
 import software.amazon.awssdk.http.apache.internal.conn.ClientConnectionManagerFactory;
 import software.amazon.awssdk.http.apache.internal.conn.IdleConnectionReaper;
@@ -81,6 +88,7 @@
 import software.amazon.awssdk.http.apache.internal.impl.ApacheSdkHttpClient;
 import software.amazon.awssdk.http.apache.internal.impl.ConnectionManagerAwareHttpClient;
 import software.amazon.awssdk.http.apache.internal.utils.ApacheUtils;
+import software.amazon.awssdk.metrics.MetricCollector;
 import software.amazon.awssdk.utils.AttributeMap;
 import software.amazon.awssdk.utils.Logger;
 import software.amazon.awssdk.utils.Validate;
@@ -206,11 +214,15 @@ private boolean isProxyEnabled(ProxyConfiguration proxyConfiguration) {
 
     @Override
     public ExecutableHttpRequest prepareRequest(HttpExecuteRequest request) {
+        MetricCollector metricCollector = request.metricCollector().orElseGet(NoOpMetricCollector::create);
+        metricCollector.reportMetric(HTTP_CLIENT_NAME, clientName());
         HttpRequestBase apacheRequest = toApacheRequest(request);
         return new ExecutableHttpRequest() {
             @Override
             public HttpExecuteResponse call() throws IOException {
-                return execute(apacheRequest);
+                HttpExecuteResponse executeResponse = execute(apacheRequest);
+                collectPoolMetric(metricCollector);
+                return executeResponse;
             }
 
             @Override
@@ -283,6 +295,18 @@ private ApacheHttpRequestConfig createRequestConfig(DefaultBuilder builder,
                                       .build();
     }
 
+    private void collectPoolMetric(MetricCollector metricCollector) {
+        HttpClientConnectionManager cm = httpClient.getHttpClientConnectionManager();
+        if (cm instanceof PoolingHttpClientConnectionManager) {
+            PoolingHttpClientConnectionManager poolingCm = (PoolingHttpClientConnectionManager) cm;
+            PoolStats totalStats = poolingCm.getTotalStats();
+            metricCollector.reportMetric(MAX_CONNECTIONS, totalStats.getMax());
+            metricCollector.reportMetric(AVAILABLE_CONNECTIONS, totalStats.getAvailable());
+            metricCollector.reportMetric(LEASED_CONNECTIONS, totalStats.getLeased());
+            metricCollector.reportMetric(PENDING_CONNECTION_ACQUIRES, totalStats.getPending());
+        }
+    }
+
     @Override
     public String clientName() {
         return CLIENT_NAME;

http-clients/apache-client/src/main/java/software/amazon/awssdk/http/apache/internal/NoOpMetricCollector.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package software.amazon.awssdk.http.apache.internal;
+
+import software.amazon.awssdk.annotations.SdkInternalApi;
+import software.amazon.awssdk.metrics.MetricCollection;
+import software.amazon.awssdk.metrics.MetricCollector;
+import software.amazon.awssdk.metrics.SdkMetric;
+
+/**
+ * A metric collector that doesn't do anything.
+ */
+@SdkInternalApi
+public final class NoOpMetricCollector implements MetricCollector {
+    private static final NoOpMetricCollector INSTANCE = new NoOpMetricCollector();
+
+    @Override
+    public String name() {
+        return "NoOp";
+    }
+
+    @Override
+    public <T> void reportMetric(SdkMetric<T> metric, T data) {
+    }
+
+    @Override
+    public MetricCollector createChild(String name) {
+        throw new UnsupportedOperationException("No op collector does not support createChild");
+    }
+
+    @Override
+    public MetricCollection collect() {
+        throw new UnsupportedOperationException("No op collector does not support collect");
+    }
+
+    public static NoOpMetricCollector create() {
+        return INSTANCE;
+    }
+}