add configuration about multiple check interval and fix set peerID of exit span failed

apm-sniffer/apm-agent-core/src/main/java/org/skywalking/apm/agent/core/conf/Config.java

@@ -34,7 +34,18 @@ public class Config {
     }
 
     public static class Collector {
-        public static long DISCOVERY_CHECK_INTERVAL = 60 * 1000;
+        /**
+         * grpc channel status check interval
+         */
+        public static long GRPC_CHANNEL_CHECK_INTERVAL = 30;
+        /**
+         * application and service registry check interval
+         */
+        public static long APP_AND_SERVICE_REGISTER_CHECK_INTERVAL = 10;
+        /**
+         * discovery rest check interval
+         */
+        public static long DISCOVERY_CHECK_INTERVAL = 60;
         /**
          * Collector REST-Service address.
          * e.g.
@@ -46,7 +57,7 @@ public class Config {
         /**
          * Collector service discovery REST service name
          */
-        public static String DISCOVERY_SERVICE_NAME = "grpc/addresses";
+        public static String DISCOVERY_SERVICE_NAME = "/grpc/addresses";
     }
 
     public static class Buffer {

apm-sniffer/apm-agent-core/src/main/java/org/skywalking/apm/agent/core/context/trace/ExitSpan.java

@@ -108,10 +108,12 @@ public class ExitSpan extends AbstractTracingSpan {
 
     @Override public SpanObject.Builder transform() {
         SpanObject.Builder spanBuilder = super.transform();
-        if (peerId == DictionaryUtil.nullValue()) {
+        if (peerId != DictionaryUtil.nullValue()) {
             spanBuilder.setPeerId(peerId);
         } else {
-            spanBuilder.setPeer(peer);
+            if (peer != null) {
+                spanBuilder.setPeer(peer);
+            }
         }
         return spanBuilder;
     }

apm-sniffer/apm-agent-core/src/main/java/org/skywalking/apm/agent/core/remote/AppAndServiceRegisterClient.java

@@ -69,7 +69,7 @@ public class AppAndServiceRegisterClient implements BootService, GRPCChannelList
     public void boot() throws Throwable {
         applicationRegisterFuture = Executors
             .newSingleThreadScheduledExecutor()
-            .scheduleAtFixedRate(this, 0, 10, TimeUnit.SECONDS);
+            .scheduleAtFixedRate(this, 0, Config.Collector.APP_AND_SERVICE_REGISTER_CHECK_INTERVAL, TimeUnit.SECONDS);
     }
 
     @Override

apm-sniffer/apm-agent-core/src/main/java/org/skywalking/apm/agent/core/remote/CollectorDiscoveryService.java

@@ -20,7 +20,7 @@ public class CollectorDiscoveryService implements BootService {
     public void boot() throws Throwable {
         Executors.newSingleThreadScheduledExecutor()
             .scheduleAtFixedRate(new DiscoveryRestServiceClient(), 0,
-                Config.Collector.DISCOVERY_CHECK_INTERVAL, TimeUnit.MILLISECONDS);
+                Config.Collector.DISCOVERY_CHECK_INTERVAL, TimeUnit.SECONDS);
     }
 
     @Override

apm-sniffer/apm-agent-core/src/main/java/org/skywalking/apm/agent/core/remote/GRPCChannelManager.java

@@ -18,6 +18,8 @@ import org.skywalking.apm.agent.core.conf.RemoteDownstreamConfig;
 import org.skywalking.apm.logging.ILog;
 import org.skywalking.apm.logging.LogManager;
 
+import static org.skywalking.apm.agent.core.conf.Config.Collector.GRPC_CHANNEL_CHECK_INTERVAL;
+
 /**
  * @author wusheng
  */
@@ -29,7 +31,6 @@ public class GRPCChannelManager implements BootService, Runnable {
     private volatile boolean reconnect = true;
     private Random random = new Random();
     private List<GRPCChannelListener> listeners = Collections.synchronizedList(new LinkedList<GRPCChannelListener>());
-    private final int retryCycle = 30;
 
     @Override
     public void beforeBoot() throws Throwable {
@@ -40,7 +41,7 @@ public class GRPCChannelManager implements BootService, Runnable {
     public void boot() throws Throwable {
         connectCheckFuture = Executors
             .newSingleThreadScheduledExecutor()
-            .scheduleAtFixedRate(this, 0, retryCycle, TimeUnit.SECONDS);
+            .scheduleAtFixedRate(this, 0, GRPC_CHANNEL_CHECK_INTERVAL, TimeUnit.SECONDS);
     }
 
     @Override
@@ -75,7 +76,7 @@ public class GRPCChannelManager implements BootService, Runnable {
                 }
             }
 
-            logger.debug("Selected collector grpc service is not available. Wait {} seconds to retry", retryCycle);
+            logger.debug("Selected collector grpc service is not available. Wait {} seconds to retry", GRPC_CHANNEL_CHECK_INTERVAL);
         }
     }
 

apm-sniffer/apm-agent-core/src/test/java/org/skywalking/apm/agent/core/remote/GRPCChannelManagerTest.java

@@ -17,6 +17,7 @@ import org.mockito.Spy;
 import org.powermock.core.classloader.annotations.PrepareForTest;
 import org.powermock.modules.junit4.PowerMockRunner;
 import org.powermock.reflect.Whitebox;
+import org.skywalking.apm.agent.core.conf.Config;
 import org.skywalking.apm.agent.core.conf.RemoteDownstreamConfig;
 import org.skywalking.apm.agent.core.test.tools.AgentServiceRule;
 
@@ -52,7 +53,7 @@ public class GRPCChannelManagerTest {
         List<String> grpcServers = new ArrayList<String>();
         grpcServers.add("127.0.0.1:2181");
         RemoteDownstreamConfig.Collector.GRPC_SERVERS = grpcServers;
-        Whitebox.setInternalState(grpcChannelManager, "retryCycle", 1);
+        Config.Collector.GRPC_CHANNEL_CHECK_INTERVAL = 1;
 
         mockStatic(NettyChannelBuilder.class);
         when(NettyChannelBuilder.forAddress(anyString(), anyInt())).thenReturn(mock);

apm-sniffer/apm-sdk-plugin/mongodb-3.x-plugin/src/main/java/org/skywalking/apm/plugin/mongodb/v3/define/MongoDBInstrumentation.java

 package org.skywalking.apm.plugin.mongodb.v3.define;
 
-import com.mongodb.connection.Cluster;
 import net.bytebuddy.description.method.MethodDescription;
 import net.bytebuddy.matcher.ElementMatcher;
 import org.skywalking.apm.agent.core.plugin.interceptor.ConstructorInterceptPoint;
@@ -9,7 +8,7 @@ import org.skywalking.apm.agent.core.plugin.interceptor.enhance.ClassInstanceMet
 import org.skywalking.apm.agent.core.plugin.match.ClassMatch;
 
 import static net.bytebuddy.matcher.ElementMatchers.named;
-import static net.bytebuddy.matcher.ElementMatchers.takesArgument;
+import static org.skywalking.apm.agent.core.plugin.bytebuddy.ArgumentTypeNameMatch.takesArgumentWithType;
 import static org.skywalking.apm.agent.core.plugin.match.NameMatch.byName;
 
 public class MongoDBInstrumentation extends ClassInstanceMethodsEnhancePluginDefine {
@@ -24,7 +23,7 @@ public class MongoDBInstrumentation extends ClassInstanceMethodsEnhancePluginDef
             new ConstructorInterceptPoint() {
                 @Override
                 public ElementMatcher<MethodDescription> getConstructorMatcher() {
-                    return takesArgument(1, Cluster.class);
+                    return takesArgumentWithType(0, "com.mongodb.connection.Cluster");
                 }
 
                 @Override