Support direct server setting in agent. (#975)

* Support direct server setting in agent.

* Fix format.

* Add direct_servers check (#981)

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

@@ -80,11 +80,24 @@ public class Config {
          */
         public static long DISCOVERY_CHECK_INTERVAL = 60;
         /**
-         * Collector REST-Service address. e.g. SERVERS="127.0.0.1:8080"  for single collector node.
-         * SERVERS="10.2.45.126:8080,10.2.45.127:7600"  for multi collector nodes.
+         * Collector naming/jetty service addresses.
+         * Primary address setting.
+         *
+         * e.g.
+         * SERVERS="127.0.0.1:10800"  for single collector node.
+         * SERVERS="10.2.45.126:10800,10.2.45.127:10800"  for multi collector nodes.
          */
         public static String SERVERS = "";
 
+        /**
+         * Collector agent_gRPC/grpc service addresses.
+         * Secondary address setting, only effect when #SERVERS is empty.
+         *
+         * By using this, no discovery mechanism provided. The agent only uses these addresses to uplink data.
+         *
+         */
+        public static String DIRECT_SERVERS = "";
+
         /**
          * Collector service discovery REST service name
          */

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

@@ -73,8 +73,8 @@ public class SnifferConfigInitializer {
         if (StringUtil.isEmpty(Config.Agent.APPLICATION_CODE)) {
             throw new ExceptionInInitializerError("`agent.application_code` is missing.");
         }
-        if (StringUtil.isEmpty(Config.Collector.SERVERS)) {
-            throw new ExceptionInInitializerError("`collector.servers` is missing.");
+        if (StringUtil.isEmpty(Config.Collector.SERVERS) && StringUtil.isEmpty(Config.Collector.DIRECT_SERVERS)) {
+            throw new ExceptionInInitializerError("`collector.direct_servers` and `collector.servers` cannot be empty at the same time.");
         }
 
         IS_INIT_COMPLETED = true;

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

@@ -18,16 +18,19 @@
 
 package org.apache.skywalking.apm.agent.core.remote;
 
-import java.util.concurrent.Executors;
-import java.util.concurrent.ScheduledFuture;
-import java.util.concurrent.TimeUnit;
 import org.apache.skywalking.apm.agent.core.boot.BootService;
 import org.apache.skywalking.apm.agent.core.boot.DefaultNamedThreadFactory;
 import org.apache.skywalking.apm.agent.core.conf.Config;
+import org.apache.skywalking.apm.agent.core.conf.RemoteDownstreamConfig;
 import org.apache.skywalking.apm.agent.core.logging.api.ILog;
 import org.apache.skywalking.apm.agent.core.logging.api.LogManager;
 import org.apache.skywalking.apm.util.RunnableWithExceptionProtection;
 
+import java.util.Arrays;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+
 /**
  * The <code>CollectorDiscoveryService</code> is responsible for start {@link DiscoveryRestServiceClient}.
  *
@@ -38,22 +41,34 @@ public class CollectorDiscoveryService implements BootService {
     private ScheduledFuture<?> future;
 
     @Override
-    public void beforeBoot() throws Throwable {
+    public void beforeBoot() {
 
     }
 
     @Override
-    public void boot() throws Throwable {
+    public void boot() {
         DiscoveryRestServiceClient discoveryRestServiceClient = new DiscoveryRestServiceClient();
-        discoveryRestServiceClient.run();
-        future = Executors.newSingleThreadScheduledExecutor(new DefaultNamedThreadFactory("CollectorDiscoveryService"))
-            .scheduleAtFixedRate(new RunnableWithExceptionProtection(discoveryRestServiceClient,
-                    new RunnableWithExceptionProtection.CallbackWhenException() {
-                        @Override public void handle(Throwable t) {
+        if (discoveryRestServiceClient.hasNamingServer()) {
+            discoveryRestServiceClient.run();
+            future = Executors.newSingleThreadScheduledExecutor(
+                    new DefaultNamedThreadFactory("CollectorDiscoveryService"))
+                    .scheduleAtFixedRate(new RunnableWithExceptionProtection(discoveryRestServiceClient, new RunnableWithExceptionProtection.CallbackWhenException() {
+                        @Override
+                        public void handle(Throwable t) {
                             logger.error("unexpected exception.", t);
                         }
-                    }), Config.Collector.DISCOVERY_CHECK_INTERVAL,
-                Config.Collector.DISCOVERY_CHECK_INTERVAL, TimeUnit.SECONDS);
+                    }),
+                            Config.Collector.DISCOVERY_CHECK_INTERVAL,
+                            Config.Collector.DISCOVERY_CHECK_INTERVAL,
+                            TimeUnit.SECONDS);
+        } else {
+            if (Config.Collector.DIRECT_SERVERS == null || Config.Collector.DIRECT_SERVERS.trim().length() == 0) {
+                logger.error("Collector server and direct server addresses are both not set.");
+                logger.error("Agent will not uplink any data.");
+                return;
+            }
+            RemoteDownstreamConfig.Collector.GRPC_SERVERS = Arrays.asList(Config.Collector.DIRECT_SERVERS.split(","));
+        }
     }
 
     @Override
@@ -63,6 +78,8 @@ public class CollectorDiscoveryService implements BootService {
 
     @Override
     public void shutdown() throws Throwable {
-        future.cancel(true);
+        if (future != null) {
+            future.cancel(true);
+        }
     }
 }

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

@@ -22,10 +22,6 @@ package org.apache.skywalking.apm.agent.core.remote;
 import com.google.gson.Gson;
 import com.google.gson.JsonArray;
 import com.google.gson.JsonElement;
-import java.io.IOException;
-import java.util.LinkedList;
-import java.util.List;
-import java.util.Random;
 import org.apache.http.client.config.RequestConfig;
 import org.apache.http.client.methods.CloseableHttpResponse;
 import org.apache.http.client.methods.HttpGet;
@@ -36,6 +32,11 @@ import org.apache.skywalking.apm.agent.core.conf.Config;
 import org.apache.skywalking.apm.agent.core.logging.api.ILog;
 import org.apache.skywalking.apm.agent.core.logging.api.LogManager;
 
+import java.io.IOException;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Random;
+
 import static org.apache.skywalking.apm.agent.core.conf.RemoteDownstreamConfig.Collector.GRPC_SERVERS;
 
 /**
@@ -55,7 +56,7 @@ public class DiscoveryRestServiceClient implements Runnable {
 
     public DiscoveryRestServiceClient() {
         if (Config.Collector.SERVERS == null || Config.Collector.SERVERS.trim().length() == 0) {
-            logger.warn("Collector server not configured.");
+            logger.warn("Collector server not set.");
             return;
         }
 
@@ -64,7 +65,10 @@ public class DiscoveryRestServiceClient implements Runnable {
         if (serverList.length > 0) {
             selectedServer = r.nextInt(serverList.length);
         }
+    }
 
+    boolean hasNamingServer() {
+        return serverList != null && serverList.length > 0;
     }
 
     @Override
@@ -138,9 +142,9 @@ public class DiscoveryRestServiceClient implements Runnable {
         }
         HttpGet httpGet = new HttpGet("http://" + serverList[selectedServer] + Config.Collector.DISCOVERY_SERVICE_NAME);
         RequestConfig requestConfig = RequestConfig.custom()
-            .setConnectTimeout(HTTP_CONNECT_TIMEOUT)
-            .setConnectionRequestTimeout(HTTP_CONNECTION_REQUEST_TIMEOUT)
-            .setSocketTimeout(HTTP_SOCKET_TIMEOUT).build();
+                .setConnectTimeout(HTTP_CONNECT_TIMEOUT)
+                .setConnectionRequestTimeout(HTTP_CONNECTION_REQUEST_TIMEOUT)
+                .setSocketTimeout(HTTP_SOCKET_TIMEOUT).build();
         httpGet.setConfig(requestConfig);
         return httpGet;
     }

apm-sniffer/config/agent.config

@@ -17,11 +17,21 @@ agent.application_code=Your_ApplicationName
 # agent.is_open_debugging_class = true
 
 # Server addresses.
+# Primary address setting.
+#
 # Mapping to `naming/jetty/ip:port` in `config/application.yml` of Collector.
 # Examples：
 # Single collector：SERVERS="127.0.0.1:8080"
 # Collector cluster：SERVERS="10.2.45.126:8080,10.2.45.127:7600"
 collector.servers=127.0.0.1:10800
 
+# Collector agent_gRPC/grpc service addresses.
+# Secondary address setting, only effect when "collector.servers" is empty.
+# By using this, no discovery mechanism provided. The agent only uses these addresses to uplink data.
+# Recommend to use this only when collector cluster IPs are unreachable from agent side. Such as:
+#   1. Agent and collector cluster are in different VPC in Cloud.
+#   2. Agent uplinks data to collector cluster through Internet.
+# collector.direct_servers=www.skywalking.service.io
+
 # Logging level
 logging.level=DEBUG