improved logging of replication operations received from replicas

java/com.sap.sailing.www/release_notes_admin.html

@@ -28,6 +28,8 @@
                 <li>The Riot server listening for WindBot data now properly implements connection closing upon not having
                     received device heartbeat messages for more than 30s.</li>
                 <li>Fixed parsing of X-Forwarded-For header, now reporting the correct client IP in case of multiple proxies along the way.</li>
+                <li>Improved logging in case operations received from replicas are being applied. The log entry now shows the name of the server
+                    where the operation originated from.</li>
           </ul>
           <h2 class="articleSubheadline">March 2025</h2>
           <ul class="bulletList">

java/com.sap.sse.replication.interfaces/src/com/sap/sse/replication/OperationWithResult.java

@@ -3,6 +3,7 @@ package com.sap.sse.replication;
 import java.io.ObjectOutputStream;
 import java.io.Serializable;
 
+import com.sap.sse.ServerInfo;
 import com.sap.sse.operationaltransformation.Operation;
 
 /**
@@ -82,4 +83,12 @@ public interface OperationWithResult<S, R> extends Operation<S>, Serializable {
         }
     }
 
+    /**
+     * Returns {@code null} by default; however, operations that originated on a different server and were sent
+     * to their primary will return their {@link ServerInfo#getName() server name}. This can be used, e.g., for
+     * debug output.
+     */
+    default String getOriginServerName() {
+        return null;
+    }
 }

java/com.sap.sse.replication.interfaces/src/com/sap/sse/replication/OperationWithResultWithIdWrapper.java

@@ -3,6 +3,7 @@ package com.sap.sse.replication;
 import java.io.Serializable;
 import java.util.UUID;
 
+import com.sap.sse.ServerInfo;
 import com.sap.sse.common.WithID;
 
 /**
@@ -19,6 +20,7 @@ public class OperationWithResultWithIdWrapper<S, R> implements OperationWithResu
     private static final long serialVersionUID = -5435955633510008283L;
     private final Serializable id;
     private final OperationWithResult<S, R> delegate;
+    private final String originServerName;
 
     /**
      * Creates a new UUID for this wrapper operation
@@ -34,6 +36,7 @@ public class OperationWithResultWithIdWrapper<S, R> implements OperationWithResu
         super();
         this.id = id;
         this.delegate = delegate;
+        this.originServerName = delegate.getOriginServerName() == null ? ServerInfo.getName() : delegate.getOriginServerName();
     }
 
     /**
@@ -41,7 +44,7 @@ public class OperationWithResultWithIdWrapper<S, R> implements OperationWithResu
      */
     @Override
     public Class<?> getClassForLogging() {
-        return delegate.getClass();
+        return delegate.getClassForLogging();
     }
     
     @Override
@@ -94,8 +97,13 @@ public class OperationWithResultWithIdWrapper<S, R> implements OperationWithResu
         return id;
     }
     
+    @Override
+    public String getOriginServerName() {
+        return originServerName;
+    }
+
     @Override
     public String toString() {
-        return ""+delegate+" with ID "+getId();
+        return ""+delegate+" with ID "+getId()+(originServerName==null?"":(" from server \""+getOriginServerName()+"\""));
     }
 }

java/com.sap.sse.replication/src/com/sap/sse/replication/impl/ReplicationServlet.java

@@ -300,6 +300,7 @@ public class ReplicationServlet extends AbstractHttpServlet {
         }
         Thread.currentThread().setContextClassLoader(oldContextClassLoader);
         logger.info("Applying operation of type " + operation.getClassForLogging().getName()
+                + (operation.getOriginServerName() == null ? "" : (" originating from server \""+operation.getOriginServerName()+"\""))
                 + " received from replica to replicable " + replicable.toString());
         try {
             replicable.apply(operation);