Client side retry and logging to CAT

apollo-client/src/main/java/com/ctrip/apollo/ConfigService.java

@@ -4,6 +4,7 @@ import com.ctrip.apollo.core.ConfigConsts;
 import com.ctrip.apollo.internals.ConfigManager;
 import com.ctrip.apollo.spi.ConfigFactory;
 import com.ctrip.apollo.spi.ConfigRegistry;
+import com.dianping.cat.Cat;
 
 import org.codehaus.plexus.PlexusContainer;
 import org.codehaus.plexus.component.repository.exception.ComponentLookupException;
@@ -36,6 +37,7 @@ public class ConfigService {
    * @return config instance
    */
   public static Config getConfig(String namespace) {
+    Cat.logEvent("Apollo.Client.Version", Apollo.VERSION);
     return getManager().getConfig(namespace);
   }
 
@@ -43,6 +45,7 @@ public class ConfigService {
     try {
       return s_instance.m_container.lookup(ConfigManager.class);
     } catch (ComponentLookupException ex) {
+      Cat.logError(ex);
       throw new IllegalStateException("Unable to load ConfigManager!", ex);
     }
   }
@@ -51,6 +54,7 @@ public class ConfigService {
     try {
       return s_instance.m_container.lookup(ConfigRegistry.class);
     } catch (ComponentLookupException ex) {
+      Cat.logError(ex);
       throw new IllegalStateException("Unable to load ConfigRegistry!", ex);
     }
   }
@@ -60,7 +64,7 @@ public class ConfigService {
   }
 
   /**
-   * Manually set the config for the namespace specified, use with caution!
+   * Manually set the config for the namespace specified, use with caution.
    * @param namespace the namespace
    * @param config the config instance
    */
@@ -78,7 +82,7 @@ public class ConfigService {
   }
 
   /**
-   * Manually set the config factory for the namespace specified, use with caution!
+   * Manually set the config factory for the namespace specified, use with caution.
    * @param namespace the namespace
    * @param factory the factory instance
    */

apollo-client/src/main/java/com/ctrip/apollo/enums/PropertyChangeType.java

@@ -5,17 +5,5 @@ package com.ctrip.apollo.enums;
  * @author Jason Song(song_s@ctrip.com)
  */
 public enum PropertyChangeType {
-  NEW("New"),
-  MODIFIED("Modified"),
-  DELETED("Deleted");
-
-  private String type;
-
-  PropertyChangeType(String type) {
-    this.type = type;
-  }
-
-  public String getType() {
-    return type;
-  }
+  NEW, MODIFIED, DELETED
 }

apollo-client/src/main/java/com/ctrip/apollo/env/Apollo.java → apollo-client/src/main/java/com/ctrip/apollo/env/ClientEnvironment.java

@@ -5,7 +5,7 @@ import com.google.common.base.Strings;
 import com.ctrip.apollo.core.enums.Env;
 import com.ctrip.framework.foundation.Foundation;
 
-public class Apollo {
+public class ClientEnvironment {
   private static Env s_env;
   private static String s_appId;
   private static String s_cluster;
@@ -39,6 +39,7 @@ public class Apollo {
         s_env = Env.LPT;
         break;
       case "FAT":
+      case "FWS":
         s_env = Env.FAT;
         break;
       case "UAT":

apollo-client/src/main/java/com/ctrip/apollo/internals/AbstractConfig.java

@@ -9,6 +9,7 @@ import com.ctrip.apollo.ConfigChangeListener;
 import com.ctrip.apollo.enums.PropertyChangeType;
 import com.ctrip.apollo.model.ConfigChange;
 import com.ctrip.apollo.model.ConfigChangeEvent;
+import com.dianping.cat.Cat;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -36,6 +37,7 @@ public abstract class AbstractConfig implements Config {
       try {
         listener.onChange(changeEvent);
       } catch (Throwable ex) {
+        Cat.logError(ex);
         logger.error("Failed to invoke config change listener {}", listener.getClass(), ex);
       }
     }

apollo-client/src/main/java/com/ctrip/apollo/internals/AbstractConfigRepository.java

@@ -2,6 +2,8 @@ package com.ctrip.apollo.internals;
 
 import com.google.common.collect.Lists;
 
+import com.dianping.cat.Cat;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -19,6 +21,7 @@ public abstract class AbstractConfigRepository implements ConfigRepository {
     try {
       sync();
     } catch (Throwable ex) {
+      Cat.logError(ex);
       logger.error("Sync config failed with repository {}", this.getClass(), ex);
     }
   }
@@ -42,6 +45,7 @@ public abstract class AbstractConfigRepository implements ConfigRepository {
       try {
         listener.onRepositoryChange(namespace, newProperties);
       } catch (Throwable ex) {
+        Cat.logError(ex);
         logger.error("Failed to invoke repository change listener {}", listener.getClass(), ex);
       }
     }

apollo-client/src/main/java/com/ctrip/apollo/internals/ConfigServiceLocator.java

 package com.ctrip.apollo.internals;
 
+import com.google.common.collect.Lists;
+import com.google.gson.reflect.TypeToken;
+
 import com.ctrip.apollo.core.dto.ServiceDTO;
 import com.ctrip.apollo.util.ConfigUtil;
 import com.ctrip.apollo.util.http.HttpRequest;
 import com.ctrip.apollo.util.http.HttpResponse;
 import com.ctrip.apollo.util.http.HttpUtil;
+import com.dianping.cat.Cat;
+import com.dianping.cat.message.Message;
+import com.dianping.cat.message.Transaction;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 import org.unidal.lookup.annotation.Inject;
 import org.unidal.lookup.annotation.Named;
 
-import java.util.ArrayList;
+import java.lang.reflect.Type;
 import java.util.List;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
 
 @Named(type = ConfigServiceLocator.class)
 public class ConfigServiceLocator {
-  private static final Logger logger = LoggerFactory.getLogger(ConfigServiceLocator.class);
   @Inject
   private HttpUtil m_httpUtil;
   @Inject
   private ConfigUtil m_configUtil;
-  private List<ServiceDTO> serviceCaches = new ArrayList<>();
+  private AtomicReference<List<ServiceDTO>> m_configServices;
+  private Type m_responseType;
+
+  public ConfigServiceLocator() {
+    List<ServiceDTO> initial = Lists.newArrayList();
+    m_configServices = new AtomicReference<>(initial);
+    m_responseType = new TypeToken<List<ServiceDTO>>() {
+    }.getType();
+  }
 
   /**
    * Get the config service info from remote meta server.
+   *
    * @return the services dto
    */
   public List<ServiceDTO> getConfigServices() {
+    if (m_configServices.get().isEmpty()) {
+      updateConfigServices();
+    }
+
+    return m_configServices.get();
+  }
+
+  //TODO periodically update config services
+  private void updateConfigServices() {
     String domainName = m_configUtil.getMetaServerDomainName();
     String url = domainName + "/services/config";
 
     HttpRequest request = new HttpRequest(url);
+    int maxRetries = 5;
+    Throwable exception = null;
+
+    for (int i = 0; i < maxRetries; i++) {
+      Transaction transaction = Cat.newTransaction("Apollo.MetaService", "getConfigService");
+      transaction.addData("Url", url);
+      try {
+        HttpResponse<List<ServiceDTO>> response = m_httpUtil.doGet(request, m_responseType);
+        m_configServices.set(response.getBody());
+        Cat.logEvent("Apollo.Config.Services", response.getBody().toString());
+        transaction.setStatus(Message.SUCCESS);
+        return;
+      } catch (Throwable ex) {
+        Cat.logError(ex);
+        transaction.setStatus(ex);
+        exception = ex;
+      } finally {
+        transaction.complete();
+      }
 
-    try {
-      HttpResponse<ServiceDTO[]> response = m_httpUtil.doGet(request, ServiceDTO[].class);
-      ServiceDTO[] services = response.getBody();
-      if (services != null && services.length > 0) {
-        serviceCaches.clear();
-        for (ServiceDTO service : services) {
-          serviceCaches.add(service);
-        }
+      try {
+        TimeUnit.SECONDS.sleep(1);
+      } catch (InterruptedException e) {
+        //ignore
       }
-    } catch (Throwable ex) {
-      logger.error("Get config services failed", ex);
-      throw new RuntimeException("Get config services failed", ex);
     }
 
-    return serviceCaches;
+    throw new RuntimeException("Get config services failed", exception);
   }
 }

apollo-client/src/main/java/com/ctrip/apollo/internals/DefaultConfig.java

@@ -50,6 +50,7 @@ public class DefaultConfig extends AbstractConfig implements RepositoryChangeLis
     } catch (Throwable ex) {
       String message = String.format("Init Apollo Local Config failed - namespace: %s",
           m_namespace);
+      Cat.logError(ex);
       logger.error(message, ex);
     }
   }
@@ -161,8 +162,8 @@ public class DefaultConfig extends AbstractConfig implements RepositoryChangeLis
       try {
         properties.load(in);
       } catch (IOException ex) {
-        logger.error("Load resource config for namespace {} failed", namespace, ex);
         Cat.logError(ex);
+        logger.error("Load resource config for namespace {} failed", namespace, ex);
       } finally {
         try {
           in.close();

apollo-client/src/main/java/com/ctrip/apollo/internals/LocalFileConfigRepository.java

@@ -34,7 +34,8 @@ public class LocalFileConfigRepository extends AbstractConfigRepository
 
   /**
    * Constructor.
-   * @param baseDir the base dir for this local file config repository
+   *
+   * @param baseDir   the base dir for this local file config repository
    * @param namespace the namespace
    */
   public LocalFileConfigRepository(File baseDir, String namespace) {
@@ -44,6 +45,7 @@ public class LocalFileConfigRepository extends AbstractConfigRepository
     try {
       m_configUtil = m_container.lookup(ConfigUtil.class);
     } catch (ComponentLookupException ex) {
+      Cat.logError(ex);
       throw new IllegalStateException("Unable to load component!", ex);
     }
     this.trySync();
@@ -86,6 +88,7 @@ public class LocalFileConfigRepository extends AbstractConfigRepository
     try {
       m_fileProperties = this.loadFromLocalCacheFile(m_baseDir, m_namespace);
     } catch (Throwable ex) {
+      Cat.logError(ex);
       ex.printStackTrace();
       //ignore
     }
@@ -107,9 +110,8 @@ public class LocalFileConfigRepository extends AbstractConfigRepository
       Properties properties = m_fallback.getConfig();
       updateFileProperties(properties);
     } catch (Throwable ex) {
-      String message =
-          String.format("Sync config from fallback repository %s failed", m_fallback.getClass());
-      logger.warn(message, ex);
+      Cat.logError(ex);
+      logger.warn("Sync config from fallback repository {} failed", m_fallback.getClass(), ex);
     }
   }
 
@@ -136,9 +138,9 @@ public class LocalFileConfigRepository extends AbstractConfigRepository
         properties = new Properties();
         properties.load(in);
       } catch (IOException ex) {
-        logger.error("Loading config from local cache file {} failed", file.getAbsolutePath(), ex);
         Cat.logError(ex);
-        throw ex;
+        throw new RuntimeException(String
+            .format("Loading config from local cache file %s failed", file.getAbsolutePath()), ex);
       } finally {
         try {
           if (in != null) {
@@ -149,10 +151,8 @@ public class LocalFileConfigRepository extends AbstractConfigRepository
         }
       }
     } else {
-      String message =
-          String.format("Cannot read from local cache file %s", file.getAbsolutePath());
-      logger.error(message);
-      throw new RuntimeException(message);
+      throw new RuntimeException(
+          String.format("Cannot read from local cache file %s", file.getAbsolutePath()));
     }
 
     return properties;
@@ -170,8 +170,8 @@ public class LocalFileConfigRepository extends AbstractConfigRepository
       out = new FileOutputStream(file);
       m_fileProperties.store(out, "Persisted by DefaultConfig");
     } catch (IOException ex) {
-      logger.error("Persist local cache file {} failed", file.getAbsolutePath(), ex);
       Cat.logError(ex);
+      logger.error("Persist local cache file {} failed", file.getAbsolutePath(), ex);
     } finally {
       if (out != null) {
         try {

apollo-client/src/main/java/com/ctrip/apollo/internals/RemoteConfigRepository.java

@@ -10,6 +10,9 @@ import com.ctrip.apollo.util.ConfigUtil;
 import com.ctrip.apollo.util.http.HttpRequest;
 import com.ctrip.apollo.util.http.HttpResponse;
 import com.ctrip.apollo.util.http.HttpUtil;
+import com.dianping.cat.Cat;
+import com.dianping.cat.message.Message;
+import com.dianping.cat.message.Transaction;
 
 import org.codehaus.plexus.PlexusContainer;
 import org.codehaus.plexus.component.repository.exception.ComponentLookupException;
@@ -17,10 +20,12 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.unidal.lookup.ContainerLoader;
 
+import java.util.Collections;
 import java.util.List;
 import java.util.Properties;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;
 
 /**
@@ -38,6 +43,7 @@ public class RemoteConfigRepository extends AbstractConfigRepository {
 
   /**
    * Constructor.
+   *
    * @param namespace the namespace
    */
   public RemoteConfigRepository(String namespace) {
@@ -49,6 +55,7 @@ public class RemoteConfigRepository extends AbstractConfigRepository {
       m_httpUtil = m_container.lookup(HttpUtil.class);
       m_serviceLocator = m_container.lookup(ConfigServiceLocator.class);
     } catch (ComponentLookupException ex) {
+      Cat.logError(ex);
       throw new IllegalStateException("Unable to load component!", ex);
     }
     this.m_executorService = Executors.newScheduledThreadPool(1,
@@ -110,35 +117,65 @@ public class RemoteConfigRepository extends AbstractConfigRepository {
   private ApolloConfig loadApolloConfig() {
     String appId = m_configUtil.getAppId();
     String cluster = m_configUtil.getCluster();
-    String
-        url =
-        assembleUrl(getConfigServiceUrl(), appId, cluster, m_namespace, m_configCache.get());
+    Cat.logEvent("Apollo.Client.Config", String.format("%s-%s-%s", appId, cluster, m_namespace));
+    int maxRetries = 2;
+    Throwable exception = null;
 
-    logger.info("Loading config from {}", url);
-    HttpRequest request = new HttpRequest(url);
+    List<ServiceDTO> configServices = getConfigServices();
+    for (int i = 0; i < maxRetries; i++) {
+      List<ServiceDTO> randomConfigServices = Lists.newArrayList(configServices);
+      Collections.shuffle(randomConfigServices);
 
-    try {
-      HttpResponse<ApolloConfig> response = m_httpUtil.doGet(request, ApolloConfig.class);
-      if (response.getStatusCode() == 304) {
-        logger.info("Config server responds with 304 HTTP status code.");
-        return m_configCache.get();
-      }
+      for (ServiceDTO configService : randomConfigServices) {
+        String url =
+            assembleUrl(configService.getHomepageUrl(), appId, cluster, m_namespace,
+                m_configCache.get());
+
+        logger.debug("Loading config from {}", url);
+        HttpRequest request = new HttpRequest(url);
+
+        Transaction transaction = Cat.newTransaction("Apollo.ConfigService", "queryConfig");
+        transaction.addData("Url", url);
+        try {
 
-      logger.info("Loaded config: {}", response.getBody());
+          HttpResponse<ApolloConfig> response = m_httpUtil.doGet(request, ApolloConfig.class);
+
+          transaction.addData("StatusCode", response.getStatusCode());
+          transaction.setStatus(Message.SUCCESS);
+
+          if (response.getStatusCode() == 304) {
+            logger.debug("Config server responds with 304 HTTP status code.");
+            return m_configCache.get();
+          }
+          logger.debug("Loaded config: {}", response.getBody());
 
-      return response.getBody();
-    } catch (Throwable ex) {
-      String message =
-          String.format("Load Apollo Config failed - appId: %s, cluster: %s, namespace: %s", appId,
-              cluster, m_namespace);
-      logger.error(message, ex);
-      throw new RuntimeException(message, ex);
+          return response.getBody();
+        } catch (Throwable ex) {
+          Cat.logError(ex);
+          transaction.setStatus(ex);
+          exception = ex;
+        } finally {
+          transaction.complete();
+        }
+
+      }
+
+      try {
+        TimeUnit.SECONDS.sleep(1);
+      } catch (InterruptedException e) {
+        //ignore
+      }
     }
+    String message = String.format(
+        "Load Apollo Config failed - appId: %s, cluster: %s, namespace: %s, services: %s",
+        appId, cluster, m_namespace, configServices);
+    logger.error(message, exception);
+    throw new RuntimeException(message, exception);
   }
 
   private String assembleUrl(String uri, String appId, String cluster, String namespace,
                              ApolloConfig previousConfig) {
-    String path = "/config/%s/%s";
+    String path = "config/%s/%s";
     List<String> params = Lists.newArrayList(appId, cluster);
 
     if (!Strings.isNullOrEmpty(namespace)) {
@@ -151,14 +188,18 @@ public class RemoteConfigRepository extends AbstractConfigRepository {
     }
 
     String pathExpanded = String.format(path, params.toArray());
+    if (!uri.endsWith("/")) {
+      uri += "/";
+    }
     return uri + pathExpanded;
   }
 
-  private String getConfigServiceUrl() {
+  private List<ServiceDTO> getConfigServices() {
     List<ServiceDTO> services = m_serviceLocator.getConfigServices();
     if (services.size() == 0) {
       throw new RuntimeException("No available config service");
     }
-    return services.get(0).getHomepageUrl();
+
+    return services;
   }
 }

apollo-client/src/main/java/com/ctrip/apollo/internals/SimpleConfig.java

@@ -5,6 +5,7 @@ import com.google.common.collect.Maps;
 
 import com.ctrip.apollo.model.ConfigChange;
 import com.ctrip.apollo.model.ConfigChangeEvent;
+import com.dianping.cat.Cat;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -40,6 +41,7 @@ public class SimpleConfig extends AbstractConfig implements RepositoryChangeList
     } catch (Throwable ex) {
       String message = String.format("Init Apollo Simple Config failed - namespace: %s",
           m_namespace);
+      Cat.logError(message, ex);
       logger.error(message, ex);
     }
   }

apollo-client/src/main/java/com/ctrip/apollo/spi/DefaultConfigFactory.java

@@ -5,12 +5,15 @@ import com.ctrip.apollo.core.utils.ClassLoaderUtil;
 import com.ctrip.apollo.internals.DefaultConfig;
 import com.ctrip.apollo.internals.LocalFileConfigRepository;
 import com.ctrip.apollo.internals.RemoteConfigRepository;
+import com.dianping.cat.Cat;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.unidal.lookup.annotation.Named;
 
 import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
 
 /**
  * @author Jason Song(song_s@ctrip.com)
@@ -26,10 +29,18 @@ public class DefaultConfigFactory implements ConfigFactory {
    */
   public DefaultConfigFactory() {
     m_baseDir = new File(ClassLoaderUtil.getClassPath() + CONFIG_DIR);
-    if (!m_baseDir.exists()) {
-      if(!m_baseDir.mkdir()){
-        logger.error("Creating local cache dir failed.");
-      }
+    this.checkLocalConfigCacheDir(m_baseDir);
+  }
+
+  private void checkLocalConfigCacheDir(File baseDir) {
+    if (baseDir.exists()) {
+      return;
+    }
+    try {
+      Files.createDirectory(baseDir.toPath());
+    } catch (IOException ex) {
+      Cat.logError(ex);
+      logger.error("Unable to create directory: " + baseDir, ex);
     }
   }
 

apollo-client/src/main/java/com/ctrip/apollo/util/ConfigUtil.java

@@ -5,7 +5,7 @@ import com.google.common.base.Preconditions;
 import com.ctrip.apollo.core.ConfigConsts;
 import com.ctrip.apollo.core.MetaDomainConsts;
 import com.ctrip.apollo.core.enums.Env;
-import com.ctrip.apollo.env.Apollo;
+import com.ctrip.apollo.env.ClientEnvironment;
 
 import org.unidal.lookup.annotation.Named;
 
@@ -28,7 +28,7 @@ public class ConfigUtil {
    * @throws IllegalStateException if app id is not set
    */
   public String getAppId() {
-    String appId = Apollo.getAppId();
+    String appId = ClientEnvironment.getAppId();
     Preconditions.checkState(appId != null, "app.id is not set");
     return appId;
   }
@@ -38,7 +38,7 @@ public class ConfigUtil {
    * @return the cluster name, or "default" if not specified
    */
   public String getCluster() {
-    String cluster = Apollo.getCluster();
+    String cluster = ClientEnvironment.getCluster();
     if (cluster == null) {
       cluster = ConfigConsts.CLUSTER_NAME_DEFAULT;
     }
@@ -51,7 +51,7 @@ public class ConfigUtil {
    * @throws IllegalStateException if env is set
    */
   public Env getApolloEnv() {
-    Env env = Apollo.getEnv();
+    Env env = ClientEnvironment.getEnv();
     Preconditions.checkState(env != null, "env is not set");
     return env;
   }

apollo-client/src/main/java/com/ctrip/apollo/util/http/HttpUtil.java

 package com.ctrip.apollo.util.http;
 
 import com.google.common.base.Charsets;
+import com.google.common.base.Function;
 import com.google.gson.Gson;
 
 import com.ctrip.apollo.util.ConfigUtil;
@@ -11,6 +12,7 @@ import org.unidal.lookup.annotation.Named;
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.lang.reflect.Type;
 import java.net.HttpURLConnection;
 import java.net.URL;
 
@@ -30,10 +32,43 @@ public class HttpUtil {
   /**
    * Do get operation for the http request.
    *
-   * @return the http response
+   * @param httpRequest  the request
+   * @param responseType the response type
+   * @return the response
    * @throws RuntimeException if any error happened or response code is neither 200 nor 304
    */
-  public <T> HttpResponse<T> doGet(HttpRequest httpRequest, Class<T> responseType) {
+  public <T> HttpResponse<T> doGet(HttpRequest httpRequest, final Class<T> responseType) {
+    Function<String, T> convertResponse = new Function<String, T>() {
+      @Override
+      public T apply(String input) {
+        return gson.fromJson(input, responseType);
+      }
+    };
+
+    return doGetWithSerializeFunction(httpRequest, convertResponse);
+  }
+
+  /**
+   * Do get operation for the http request.
+   *
+   * @param httpRequest  the request
+   * @param responseType the response type
+   * @return the response
+   * @throws RuntimeException if any error happened or response code is neither 200 nor 304
+   */
+  public <T> HttpResponse<T> doGet(HttpRequest httpRequest, final Type responseType) {
+    Function<String, T> convertResponse = new Function<String, T>() {
+      @Override
+      public T apply(String input) {
+        return gson.fromJson(input, responseType);
+      }
+    };
+
+    return doGetWithSerializeFunction(httpRequest, convertResponse);
+  }
+
+  private <T> HttpResponse<T> doGetWithSerializeFunction(HttpRequest httpRequest,
+                                                         Function<String, T> serializeFunction) {
     InputStream is = null;
     try {
       HttpURLConnection conn = (HttpURLConnection) new URL(httpRequest.getUrl()).openConnection();
@@ -60,7 +95,7 @@ public class HttpUtil {
       if (statusCode == 200) {
         is = conn.getInputStream();
         String content = Files.IO.INSTANCE.readFrom(is, Charsets.UTF_8.name());
-        return new HttpResponse<>(statusCode, gson.fromJson(content, responseType));
+        return new HttpResponse<>(statusCode, serializeFunction.apply(content));
       }
 
       if (statusCode == 304) {
@@ -82,7 +117,6 @@ public class HttpUtil {
         }
       }
     }
-
   }
 
 }

apollo-client/src/test/java/com/ctrip/apollo/integration/BaseIntegrationTest.java

@@ -23,7 +23,9 @@ import org.unidal.lookup.ComponentTestCase;
 
 import java.io.File;
 import java.io.IOException;
+import java.net.ServerSocket;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
@@ -33,7 +35,7 @@ import javax.servlet.http.HttpServletResponse;
  * @author Jason Song(song_s@ctrip.com)
  */
 public class BaseIntegrationTest extends ComponentTestCase {
-  private static final int PORT = 5678;
+  private static final int PORT = findFreePort();
   private static final String metaServiceUrl = "http://localhost:" + PORT;
   private static final String someAppName = "someAppName";
   private static final String someInstanceId = "someInstanceId";
@@ -86,23 +88,33 @@ public class BaseIntegrationTest extends ComponentTestCase {
 
   @After
   public void tearDown() throws Exception {
-    super.tearDown();
     if (server != null && server.isStarted()) {
       server.stop();
     }
+    super.tearDown();
+  }
+
+  protected ContextHandler mockMetaServerHandler() {
+    return mockMetaServerHandler(false);
   }
 
-  private ContextHandler mockMetaServerHandler() {
+  protected ContextHandler mockMetaServerHandler(final boolean failedAtFirstTime) {
     final ServiceDTO someServiceDTO = new ServiceDTO();
     someServiceDTO.setAppName(someAppName);
     someServiceDTO.setInstanceId(someInstanceId);
     someServiceDTO.setHomepageUrl(configServiceURL);
+    final AtomicInteger counter = new AtomicInteger(0);
 
     ContextHandler context = new ContextHandler("/services/config");
     context.setHandler(new AbstractHandler() {
       @Override
       public void handle(String target, Request baseRequest, HttpServletRequest request,
                          HttpServletResponse response) throws IOException, ServletException {
+        if (failedAtFirstTime && counter.incrementAndGet() == 1) {
+          response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
+          baseRequest.setHandled(true);
+          return;
+        }
         response.setContentType("application/json;charset=UTF-8");
         response.setStatus(HttpServletResponse.SC_OK);
 
@@ -150,4 +162,37 @@ public class BaseIntegrationTest extends ComponentTestCase {
     }
   }
 
+  /**
+   * Returns a free port number on localhost.
+   *
+   * Heavily inspired from org.eclipse.jdt.launching.SocketUtil (to avoid a dependency to JDT just because of this).
+   * Slightly improved with close() missing in JDT. And throws exception instead of returning -1.
+   *
+   * @return a free port number on localhost
+   * @throws IllegalStateException if unable to find a free port
+   */
+  private static int findFreePort() {
+    ServerSocket socket = null;
+    try {
+      socket = new ServerSocket(0);
+      socket.setReuseAddress(true);
+      int port = socket.getLocalPort();
+      try {
+        socket.close();
+      } catch (IOException e) {
+        // Ignore IOException on close()
+      }
+      return port;
+    } catch (IOException e) {
+    } finally {
+      if (socket != null) {
+        try {
+          socket.close();
+        } catch (IOException e) {
+        }
+      }
+    }
+    throw new IllegalStateException("Could not find a free TCP/IP port to start embedded Jetty HTTP Server on");
+  }
+
 }

apollo-client/src/test/java/com/ctrip/apollo/integration/ConfigIntegrationTest.java

 package com.ctrip.apollo.integration;
 
-import static org.hamcrest.core.IsEqual.equalTo;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertThat;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
+
+import com.ctrip.apollo.Config;
+import com.ctrip.apollo.ConfigChangeListener;
+import com.ctrip.apollo.ConfigService;
+import com.ctrip.apollo.core.ConfigConsts;
+import com.ctrip.apollo.core.dto.ApolloConfig;
+import com.ctrip.apollo.core.utils.ClassLoaderUtil;
+import com.ctrip.apollo.model.ConfigChangeEvent;
+
+import org.eclipse.jetty.server.Request;
+import org.eclipse.jetty.server.handler.AbstractHandler;
+import org.eclipse.jetty.server.handler.ContextHandler;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
 
 import java.io.File;
 import java.io.FileOutputStream;
@@ -12,28 +27,15 @@ import java.util.List;
 import java.util.Map;
 import java.util.Properties;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
-import org.eclipse.jetty.server.Request;
-import org.eclipse.jetty.server.handler.AbstractHandler;
-import org.eclipse.jetty.server.handler.ContextHandler;
-import org.junit.After;
-import org.junit.Before;
-import org.junit.Test;
-
-import com.ctrip.apollo.Config;
-import com.ctrip.apollo.ConfigChangeListener;
-import com.ctrip.apollo.ConfigService;
-import com.ctrip.apollo.core.ConfigConsts;
-import com.ctrip.apollo.core.dto.ApolloConfig;
-import com.ctrip.apollo.core.utils.ClassLoaderUtil;
-import com.ctrip.apollo.model.ConfigChangeEvent;
-import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.Lists;
-import com.google.common.collect.Maps;
+import static org.hamcrest.core.IsEqual.equalTo;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThat;
 
 /**
  * @author Jason Song(song_s@ctrip.com)
@@ -142,6 +144,36 @@ public class ConfigIntegrationTest extends BaseIntegrationTest {
   }
 
   @Test
+  public void testGetConfigWithNoLocalFileAndRemoteMetaServiceRetry() throws Exception {
+    String someKey = "someKey";
+    String someValue = "someValue";
+    ApolloConfig apolloConfig = assembleApolloConfig(ImmutableMap.of(someKey, someValue));
+    ContextHandler configHandler = mockConfigServerHandler(HttpServletResponse.SC_OK, apolloConfig);
+    boolean failAtFirstTime = true;
+    ContextHandler metaServerHandler = mockMetaServerHandler(failAtFirstTime);
+    startServerWithHandlers(metaServerHandler, configHandler);
+
+    Config config = ConfigService.getConfig();
+
+    assertEquals(someValue, config.getProperty(someKey, null));
+  }
+
+  @Test
+  public void testGetConfigWithNoLocalFileAndRemoteConfigServiceRetry() throws Exception {
+    String someKey = "someKey";
+    String someValue = "someValue";
+    ApolloConfig apolloConfig = assembleApolloConfig(ImmutableMap.of(someKey, someValue));
+    boolean failedAtFirstTime = true;
+    ContextHandler handler =
+        mockConfigServerHandler(HttpServletResponse.SC_OK, apolloConfig, failedAtFirstTime);
+    startServerWithHandlers(handler);
+
+    Config config = ConfigService.getConfig();
+
+    assertEquals(someValue, config.getProperty(someKey, null));
+  }
+
+  @Test
   public void testRefreshConfig() throws Exception {
     final String someKey = "someKey";
     final String someValue = "someValue";
@@ -183,12 +215,21 @@ public class ConfigIntegrationTest extends BaseIntegrationTest {
     assertEquals(anotherValue, config.getProperty(someKey, null));
   }
 
-  private ContextHandler mockConfigServerHandler(final int statusCode, final ApolloConfig result) {
+  private ContextHandler mockConfigServerHandler(final int statusCode, final ApolloConfig result,
+                                                 final boolean failedAtFirstTime) {
     ContextHandler context = new ContextHandler("/config/*");
     context.setHandler(new AbstractHandler() {
+      AtomicInteger counter = new AtomicInteger(0);
+
       @Override
       public void handle(String target, Request baseRequest, HttpServletRequest request,
-          HttpServletResponse response) throws IOException, ServletException {
+                         HttpServletResponse response) throws IOException, ServletException {
+        if (failedAtFirstTime && counter.incrementAndGet() == 1) {
+          response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
+          baseRequest.setHandled(true);
+          return;
+        }
+
         response.setContentType("application/json;charset=UTF-8");
         response.setStatus(statusCode);
 
@@ -199,6 +240,12 @@ public class ConfigIntegrationTest extends BaseIntegrationTest {
     });
 
     return context;
+
+  }
+
+
+  private ContextHandler mockConfigServerHandler(int statusCode, ApolloConfig result) {
+    return mockConfigServerHandler(statusCode, result, false);
   }
 
   private ApolloConfig assembleApolloConfig(Map<String, String> configurations) {

apollo-core/src/main/java/com/ctrip/apollo/Apollo.java

+package com.ctrip.apollo;
+
+/**
+ * @author Jason Song(song_s@ctrip.com)
+ */
+public class Apollo {
+  public final static String VERSION = "java-0.0.1-SNAPSHOT";
+}

apollo-core/src/main/java/com/ctrip/apollo/core/dto/ServiceDTO.java

 package com.ctrip.apollo.core.dto;
 
+import com.google.common.base.MoreObjects;
+
 public class ServiceDTO {
 
   private String appName;
@@ -31,4 +33,14 @@ public class ServiceDTO {
   public void setInstanceId(String instanceId) {
     this.instanceId = instanceId;
   }
+
+  @Override
+  public String toString() {
+    return MoreObjects.toStringHelper(this)
+        .omitNullValues()
+        .add("appName", appName)
+        .add("instanceId", instanceId)
+        .add("homepageUrl", homepageUrl)
+        .toString();
+  }
 }

apollo-demo/src/main/java/ApolloConfigDemo.java

 
+import com.google.common.base.Strings;
+
 import com.ctrip.apollo.Config;
 import com.ctrip.apollo.ConfigChangeListener;
 import com.ctrip.apollo.ConfigService;
@@ -37,8 +39,8 @@ public class ApolloConfigDemo implements ConfigChangeListener {
     while (true) {
       System.out.print("> ");
       String input = new BufferedReader(new InputStreamReader(System.in)).readLine();
-      if (input == null) {
-       continue;
+      if (Strings.isNullOrEmpty(input)) {
+        continue;
       }
       input = input.trim();
       if (input.equalsIgnoreCase("quit")) {