Fix start when not config in provider and don't get module in prepare stage. (#1711)

oap-server/server-library/library-module/src/main/java/org/apache/skywalking/oap/server/library/module/ModuleDefine.java

@@ -90,6 +90,9 @@ public abstract class ModuleDefine {
 
     private void copyProperties(ModuleConfig dest, Properties src, String moduleName,
         String providerName) throws IllegalAccessException {
+        if (dest == null) {
+            return;
+        }
         Enumeration<?> propertyNames = src.propertyNames();
         while (propertyNames.hasMoreElements()) {
             String propertyName = (String)propertyNames.nextElement();

oap-server/server-receiver-plugin/skywalking-mesh-receiver-plugin/src/main/java/org/apache/skywalking/aop/server/receiver/mesh/MeshReceiverProvider.java

@@ -47,6 +47,9 @@ public class MeshReceiverProvider extends ModuleProvider {
     }
 
     @Override public void prepare() throws ServiceNotProvidedException, ModuleStartException {
+    }
+
+    @Override public void start() throws ServiceNotProvidedException, ModuleStartException {
         MeshDataBufferFileCache cache = new MeshDataBufferFileCache(config);
         try {
             cache.start();
@@ -54,9 +57,6 @@ public class MeshReceiverProvider extends ModuleProvider {
         } catch (IOException e) {
             throw new ModuleStartException(e.getMessage(), e);
         }
-    }
-
-    @Override public void start() throws ServiceNotProvidedException, ModuleStartException {
         CoreRegisterLinker.setModuleManager(getManager());
         GRPCHandlerRegister service = getManager().find(CoreModule.NAME).getService(GRPCHandlerRegister.class);
         service.addHandler(new MeshGRPCHandler());

oap-server/server-starter/src/main/resources/application.yml

@@ -53,7 +53,7 @@ receiver-register:
   default:
 receiver-trace:
   default:
-    bufferPath: ../buffer/  # Path to trace buffer files, suggest to use absolute path
+    bufferPath: ../trace-buffer/  # Path to trace buffer files, suggest to use absolute path
     bufferOffsetMaxFileSize: 100 # Unit is MB
     bufferDataMaxFileSize: 500 # Unit is MB
     bufferFileCleanWhenRestart: false
@@ -61,6 +61,10 @@ receiver-jvm:
   default:
 service-mesh:
   default:
+    bufferPath: ../mesh-buffer/  # Path to trace buffer files, suggest to use absolute path
+    bufferOffsetMaxFileSize: 100 # Unit is MB
+    bufferDataMaxFileSize: 500 # Unit is MB
+    bufferFileCleanWhenRestart: false
 istio-telemetry:
   default:
 query: