Merge pull request #1949 from nobodyiam/fix-1885

add rate limter for no app id warning log

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

 package com.ctrip.framework.apollo.util;
 
+import com.google.common.util.concurrent.RateLimiter;
 import java.io.File;
 import java.util.concurrent.TimeUnit;
 
@@ -34,8 +35,10 @@ public class ConfigUtil {
   private TimeUnit configCacheExpireTimeUnit = TimeUnit.MINUTES;//1 minute
   private long longPollingInitialDelayInMills = 2000;//2 seconds
   private boolean autoUpdateInjectedSpringProperties = true;
+  private final RateLimiter warnLogRateLimiter;
 
   public ConfigUtil() {
+    warnLogRateLimiter = RateLimiter.create(0.017); // 1 warning log output per minute
     initRefreshInterval();
     initConnectTimeout();
     initReadTimeout();
@@ -55,8 +58,10 @@ public class ConfigUtil {
     String appId = Foundation.app().getAppId();
     if (Strings.isNullOrEmpty(appId)) {
       appId = ConfigConsts.NO_APPID_PLACEHOLDER;
-      logger.warn("app.id is not set, please make sure it is set in classpath:/META-INF/app.properties, now apollo " +
-          "will only load public namespace configurations!");
+      if (warnLogRateLimiter.tryAcquire()) {
+        logger.warn(
+            "app.id is not set, please make sure it is set in classpath:/META-INF/app.properties, now apollo will only load public namespace configurations!");
+      }
     }
     return appId;
   }