feat: Support retry in open api client

Author: zth9

CHANGES.md

@@ -8,6 +8,7 @@ Apollo Java 2.5.0
 
 * [Feature Provide a new open APl to return the organization list](https://github.com/apolloconfig/apollo-java/pull/102)
 * [Feature Added a new feature to get instance count by namespace.](https://github.com/apolloconfig/apollo-java/pull/103)
+* [Feature Support retry in open api client.](https://github.com/apolloconfig/apollo-java/pull/105)
 
 ------------------
 All issues and pull requests are [here](https://github.com/apolloconfig/apollo-java/milestone/5?closed=1)

apollo-openapi/src/main/java/com/ctrip/framework/apollo/openapi/client/ApolloOpenApiClient.java

@@ -17,6 +17,8 @@
 package com.ctrip.framework.apollo.openapi.client;
 
 import com.ctrip.framework.apollo.openapi.client.constant.ApolloOpenApiConstants;
+import com.ctrip.framework.apollo.openapi.client.extend.ApolloStandardHttpRequestRetryHandler;
+import com.ctrip.framework.apollo.openapi.client.extend.IdempotentHttpMethod;
 import com.ctrip.framework.apollo.openapi.client.service.AppOpenApiService;
 import com.ctrip.framework.apollo.openapi.client.service.ClusterOpenApiService;
 import com.ctrip.framework.apollo.openapi.client.service.ItemOpenApiService;
@@ -55,10 +57,13 @@ public class ApolloOpenApiClient {
   private final InstanceOpenApiService instanceService;
   private static final Gson GSON = new GsonBuilder().setDateFormat(ApolloOpenApiConstants.JSON_DATE_FORMAT).create();
 
-  private ApolloOpenApiClient(String portalUrl, String token, RequestConfig requestConfig) {
+  private ApolloOpenApiClient(String portalUrl, String token, RequestConfig requestConfig,
+      int retryCount, IdempotentHttpMethod[] idempotentHttpMethods) {
     this.portalUrl = portalUrl;
     this.token = token;
     CloseableHttpClient client = HttpClients.custom().setDefaultRequestConfig(requestConfig)
+        .setRetryHandler(retryCount > 0 ?
+            new ApolloStandardHttpRequestRetryHandler(retryCount, idempotentHttpMethods) : null)
         .setDefaultHeaders(Lists.newArrayList(new BasicHeader("Authorization", token))).build();
 
     String baseUrl = this.portalUrl + ApolloOpenApiConstants.OPEN_API_V1_PREFIX;
@@ -273,6 +278,8 @@ public static class ApolloOpenApiClientBuilder {
     private String token;
     private int connectTimeout = -1;
     private int readTimeout = -1;
+    private int retryCount = -1;
+    private IdempotentHttpMethod[] idempotentHttpMethods;
 
     /**
      * @param portalUrl The apollo portal url, e.g http://localhost:8070
@@ -306,6 +313,22 @@ public ApolloOpenApiClientBuilder withReadTimeout(int readTimeout) {
       return this;
     }
 
+    /**
+     * @param retryCount execute retry when an exception occurs, default no retry
+     */
+    public ApolloOpenApiClientBuilder withRetryCount(int retryCount) {
+      this.retryCount = retryCount;
+      return this;
+    }
+
+    /**
+     * @param idempotentHttpMethods idempotent HTTP methods will directly execute retries when exception
+     */
+    public ApolloOpenApiClientBuilder withIdempotentHttpMethods(IdempotentHttpMethod... idempotentHttpMethods) {
+      this.idempotentHttpMethods = idempotentHttpMethods;
+      return this;
+    }
+
     public ApolloOpenApiClient build() {
       Preconditions.checkArgument(!Strings.isNullOrEmpty(portalUrl), "Portal url should not be null or empty!");
       Preconditions.checkArgument(portalUrl.startsWith("http://") || portalUrl.startsWith("https://"), "Portal url should start with http:// or https://" );
@@ -322,7 +345,7 @@ public ApolloOpenApiClient build() {
       RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(connectTimeout)
           .setSocketTimeout(readTimeout).build();
 
-      return new ApolloOpenApiClient(portalUrl, token, requestConfig);
+      return new ApolloOpenApiClient(portalUrl, token, requestConfig, retryCount, idempotentHttpMethods);
     }
   }
 }

apollo-openapi/src/main/java/com/ctrip/framework/apollo/openapi/client/extend/ApolloStandardHttpRequestRetryHandler.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2022 Apollo Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License 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 com.ctrip.framework.apollo.openapi.client.extend;
+
+import com.google.common.collect.Collections2;
+import com.google.common.collect.Lists;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.Set;
+import org.apache.http.HttpRequest;
+import org.apache.http.impl.client.DefaultHttpRequestRetryHandler;
+
+import javax.net.ssl.SSLException;
+import java.net.ConnectException;
+import java.net.NoRouteToHostException;
+import java.net.UnknownHostException;
+import java.util.Arrays;
+import java.util.Locale;
+
+/**
+ * @author zth9
+ * @date 2025-05-07
+ */
+public class ApolloStandardHttpRequestRetryHandler extends DefaultHttpRequestRetryHandler {
+
+  private final Set<String> idempotentMethods;
+
+  public ApolloStandardHttpRequestRetryHandler(int retryCount, IdempotentHttpMethod[] httpMethods) {
+    super(retryCount, false, Arrays.asList(
+        UnknownHostException.class,
+        ConnectException.class,
+        NoRouteToHostException.class,
+        SSLException.class));
+    this.idempotentMethods = new HashSet<>();
+    if (httpMethods == null || httpMethods.length == 0) {
+      // default set safe idempotent http method
+      httpMethods = IdempotentHttpMethod.safe();
+    }
+    for (IdempotentHttpMethod httpMethod : httpMethods) {
+      if (httpMethod == null) {
+        continue;
+      }
+      idempotentMethods.add(httpMethod.name());
+    }
+  }
+
+  @Override
+  protected boolean handleAsIdempotent(final HttpRequest request) {
+    String method = request.getRequestLine().getMethod().toUpperCase(Locale.ROOT);
+    return idempotentMethods.contains(method);
+  }
+}

apollo-openapi/src/main/java/com/ctrip/framework/apollo/openapi/client/extend/IdempotentHttpMethod.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2022 Apollo Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License 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 com.ctrip.framework.apollo.openapi.client.extend;
+
+/**
+ * @author zth9
+ * @date 2025-05-11
+ */
+public enum IdempotentHttpMethod {
+  GET, HEAD, PUT, DELETE, OPTIONS, TRACE;
+
+  /**
+   * Usually, these methods are idempotent
+   */
+  public static IdempotentHttpMethod[] safe() {
+    return new IdempotentHttpMethod[]{GET, HEAD, OPTIONS, TRACE};
+  }
+
+  /**
+   * Standard HTTP idempotent method. While PUT and DELETE are technically idempotent, repeated
+   * requests can yield different responses—such as a 404 on a second delete
+   */
+  public static IdempotentHttpMethod[] standard() {
+    return new IdempotentHttpMethod[]{GET, HEAD, PUT, DELETE, OPTIONS, TRACE};
+  }
+}

apollo-openapi/src/test/java/com/ctrip/framework/apollo/openapi/client/ApolloOpenApiClientIntegrationTest.java

@@ -19,6 +19,7 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import com.ctrip.framework.apollo.openapi.client.extend.IdempotentHttpMethod;
 import com.ctrip.framework.apollo.openapi.dto.NamespaceReleaseDTO;
 import com.ctrip.framework.apollo.openapi.dto.OpenAppDTO;
 import com.ctrip.framework.apollo.openapi.dto.OpenAppNamespaceDTO;
@@ -63,6 +64,8 @@ ApolloOpenApiClient newClient() {
         .withToken(someToken)
         .withReadTimeout(2000 * 1000)
         .withConnectTimeout(2000 * 1000)
+        .withRetryCount(3)
+        .withIdempotentHttpMethods(IdempotentHttpMethod.safe())
         .build();
   }