Let RestClient can reuse connections

Implement #14

Change-Id: I49c0675566145e233e40f25fe0c30c9614bf2c14

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>com.baidu.hugegraph</groupId>
     <artifactId>hugegraph-common</artifactId>
-    <version>1.5.8</version>
+    <version>1.5.9</version>
 
     <name>hugegraph-common</name>
     <url>https://github.com/hugegraph/hugegraph-common</url>
@@ -66,9 +66,11 @@
         <javax.json.version>1.0</javax.json.version>
         <jsr305.version>3.0.1</jsr305.version>
         <javassist.version>3.21.0-GA</javassist.version>
-        <jersey.version>2.25.1</jersey.version>
+        <!--TODO: Update to 2.29 when released-->
+        <jersey.version>2.22</jersey.version>
         <jersey.hk2.version>2.27</jersey.hk2.version>
         <junit.version>4.12</junit.version>
+        <mockito.version>2.25.1</mockito.version>
     </properties>
 
     <dependencies>
@@ -78,6 +80,12 @@
             <artifactId>junit</artifactId>
             <version>${junit.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <version>${mockito.version}</version>
+            <scope>test</scope>
+        </dependency>
 
         <!-- Logging -->
         <dependency>
@@ -157,6 +165,11 @@
             <artifactId>jersey-media-json-jackson</artifactId>
             <version>${jersey.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.glassfish.jersey.connectors</groupId>
+            <artifactId>jersey-apache-connector</artifactId>
+            <version>${jersey.version}</version>
+        </dependency>
         <dependency>
             <groupId>org.glassfish.jersey.inject</groupId>
             <artifactId>jersey-hk2</artifactId>
@@ -199,7 +212,7 @@
                         <manifestEntries>
                             <!-- Must be on one line, otherwise the automatic
                                  upgrade script cannot replace the version number -->
-                            <Implementation-Version>1.5.8.0</Implementation-Version>
+                            <Implementation-Version>1.5.9.0</Implementation-Version>
                         </manifestEntries>
                     </archive>
                 </configuration>

src/main/java/com/baidu/hugegraph/rest/RestClient.java

@@ -19,6 +19,8 @@
 
 package com.baidu.hugegraph.rest;
 
+import static org.glassfish.jersey.apache.connector.ApacheClientProperties.CONNECTION_MANAGER;
+
 import java.util.Collection;
 import java.util.Map;
 import java.util.concurrent.Callable;
@@ -33,6 +35,9 @@
 import javax.ws.rs.core.Response;
 import javax.ws.rs.core.Variant;
 
+import org.apache.http.config.SocketConfig;
+import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
+import org.glassfish.jersey.apache.connector.ApacheConnectorProvider;
 import org.glassfish.jersey.client.ClientConfig;
 import org.glassfish.jersey.client.ClientProperties;
 import org.glassfish.jersey.client.authentication.HttpAuthenticationFeature;
@@ -45,24 +50,42 @@
 
 public abstract class RestClient {
 
-    private Client client;
-    private WebTarget target;
+    private final ClientConfig config;
+    private final Client client;
+    private final WebTarget target;
 
     public RestClient(String url, int timeout) {
-        this(url, buildConfig(timeout));
+        this(url, new ConfigBuilder().config(timeout).build());
+    }
+
+    public RestClient(String url, int timeout, int maxTotal, int maxPerRoute) {
+        this(url, new ConfigBuilder().config(timeout)
+                                     .config(timeout, maxTotal, maxPerRoute)
+                                     .build());
     }
 
     public RestClient(String url, String user, String password, int timeout) {
-        this(url, buildConfigWithBasicAuth(user, password, timeout));
+        this(url, new ConfigBuilder().config(timeout)
+                                     .config(user, password)
+                                     .build());
     }
 
+    public RestClient(String url, String user, String password, int timeout,
+                      int maxTotal, int maxPerRoute) {
+        this(url, new ConfigBuilder().config(timeout)
+                                     .config(user, password)
+                                     .config(timeout, maxTotal, maxPerRoute)
+                                     .build());
+    }
+
     public RestClient(String url, ClientConfig config) {
-        this.client = ClientBuilder.newClient(config);
+        this.config = config;
+        this.client = ClientBuilder.newClient(this.config);
         this.client.register(GZipEncoder.class);
         this.target = this.client.target(url);
     }
 
-    private Response request(Callable<Response> method) {
+    protected Response request(Callable<Response> method) {
         try {
             return method.call();
         } catch (Exception e) {
@@ -208,30 +231,64 @@ private static String encode(String raw) {
         return UriComponent.encode(raw, UriComponent.Type.PATH_SEGMENT);
     }
 
-    private static ClientConfig buildConfigWithBasicAuth(String username,
-                                                         String password,
-                                                         int timeout) {
-        ClientConfig config = buildConfig(timeout);
-        /*
-         * NOTE: don't use non-preemptive mode
-         * In non-preemptive mode the authentication information is added
-         * only when server refuses the request with 401 status code and
-         * then the request is repeated.
-         * Non-preemptive has negative impact on the performance. The advantage
-         * is that it does not send credentials when they are not needed.
-         * https://jersey.github.io/documentation/latest/client.html#d0e5461
-         */
-        config.register(HttpAuthenticationFeature.basic(username, password));
-        return config;
-    }
-
-    private static ClientConfig buildConfig(int timeout) {
-        ClientConfig config = new ClientConfig();
-        config.property(ClientProperties.CONNECT_TIMEOUT, timeout);
-        config.property(ClientProperties.READ_TIMEOUT, timeout);
-        return config;
-    }
-
     protected abstract void checkStatus(Response response,
                                         Response.Status... statuses);
+
+    private static class ConfigBuilder {
+
+        private final ClientConfig config;
+
+        public ConfigBuilder() {
+            this.config = new ClientConfig();
+        }
+
+        public ConfigBuilder config(int timeout) {
+            this.config.property(ClientProperties.CONNECT_TIMEOUT, timeout);
+            this.config.property(ClientProperties.READ_TIMEOUT, timeout);
+            return this;
+        }
+
+        public ConfigBuilder config(String username, String password) {
+            /*
+             * NOTE: don't use non-preemptive mode
+             * In non-preemptive mode the authentication information is added
+             * only when server refuses the request with 401 status code and
+             * then the request is repeated.
+             * Non-preemptive has negative impact on the performance. The
+             * advantage is it doesn't send credentials when they are not needed
+             * https://jersey.github.io/documentation/latest/client.html#d0e5461
+             */
+            this.config.register(HttpAuthenticationFeature.basic(username,
+                                                                 password));
+            return this;
+        }
+
+        public ConfigBuilder config(int timeout, int maxTotal,
+                                    int maxPerRoute) {
+            /*
+             * Using httpclient with connection pooling, and configuring the
+             * jersey connector, reference:
+             * http://www.theotherian.com/2013/08/jersey-client-2.0-httpclient-timeouts-max-connections.html
+             * https://stackoverflow.com/questions/43228051/memory-issue-with-jax-rs-using-jersey/46175943#46175943
+             *
+             * But the jersey that has been released in the maven central
+             * repository seems to have a bug.
+             * https://github.com/jersey/jersey/pull/3752
+             */
+            PoolingHttpClientConnectionManager pcm =
+                    new PoolingHttpClientConnectionManager();
+            pcm.setDefaultSocketConfig(SocketConfig.custom()
+                                                   .setSoTimeout(timeout)
+                                                   .build());
+            pcm.setMaxTotal(maxTotal);
+            pcm.setDefaultMaxPerRoute(maxPerRoute);
+            this.config.property(CONNECTION_MANAGER, pcm);
+            this.config.connectorProvider(new ApacheConnectorProvider());
+            return this;
+        }
+
+        public ClientConfig build() {
+            return this.config;
+        }
+    }
 }

src/main/java/com/baidu/hugegraph/rest/RestResult.java

@@ -34,9 +34,9 @@ public class RestResult {
 
     private static final ObjectMapper mapper = new ObjectMapper();
 
-    private int status;
-    private MultivaluedMap<String, Object> headers;
-    private String content;
+    private final int status;
+    private final MultivaluedMap<String, Object> headers;
+    private final String content;
 
     public RestResult(Response response) {
         this.status = response.getStatus();

src/main/java/com/baidu/hugegraph/util/VersionUtil.java

@@ -44,7 +44,7 @@ public static boolean match(Version version, String begin, String end) {
     /**
      * Compare if a version is greater than the other one (inclusive)
      * @param version   The version to be compared
-     * @param begin     The lower bound of the range
+     * @param other     The lower bound of the range
      * @return          true if it's greater than the other, otherwise false
      */
     public static boolean gte(String version, String other) {

src/main/java/com/baidu/hugegraph/version/CommonVersion.java

@@ -27,5 +27,5 @@ public class CommonVersion {
 
     // The second parameter of Version.of() is for all-in-one JAR
     public static final Version VERSION = Version.of(CommonVersion.class,
-                                                     "1.5.8");
+                                                     "1.5.9");
 }

src/test/java/com/baidu/hugegraph/unit/UnitTestSuite.java

@@ -30,6 +30,8 @@
 import com.baidu.hugegraph.unit.iterator.FlatMapperIteratorTest;
 import com.baidu.hugegraph.unit.iterator.MapperIteratorTest;
 import com.baidu.hugegraph.unit.perf.PerfUtilTest;
+import com.baidu.hugegraph.unit.rest.RestClientTest;
+import com.baidu.hugegraph.unit.rest.RestResultTest;
 import com.baidu.hugegraph.unit.util.BytesTest;
 import com.baidu.hugegraph.unit.util.CollectionUtilTest;
 import com.baidu.hugegraph.unit.util.HashUtilTest;
@@ -46,6 +48,8 @@
     HugeConfigTest.class,
     EventHubTest.class,
     PerfUtilTest.class,
+    RestClientTest.class,
+    RestResultTest.class,
     VersionTest.class,
 
     ExtendableIteratorTest.class,