Add new "Collecting Logger", that can be activated to "collect" logs (e.g., in an internal list), for later access (e.g., by a test, to assert if things were logged).

qqq-backend-core/src/main/java/com/kingsrook/qqq/backend/core/logging/CollectedLogMessage.java

@@ -0,0 +1,153 @@
+/*
+ * QQQ - Low-code Application Framework for Engineers.
+ * Copyright (C) 2021-2024.  Kingsrook, LLC
+ * 651 N Broad St Ste 205 # 6917 | Middletown DE 19709 | United States
+ * contact@kingsrook.com
+ * https://github.com/Kingsrook/
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.kingsrook.qqq.backend.core.logging;
+
+
+import org.apache.logging.log4j.Level;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+
+/*******************************************************************************
+ ** A log message, which can be "collected" by the QCollectingLogger.
+ *******************************************************************************/
+public class CollectedLogMessage
+{
+   private Level     level;
+   private String    message;
+   private Throwable exception;
+
+
+
+   /*******************************************************************************
+    ** Constructor
+    **
+    *******************************************************************************/
+   public CollectedLogMessage()
+   {
+   }
+
+
+
+   /*******************************************************************************
+    ** Getter for message
+    *******************************************************************************/
+   public String getMessage()
+   {
+      return (this.message);
+   }
+
+
+
+   /*******************************************************************************
+    ** Setter for message
+    *******************************************************************************/
+   public void setMessage(String message)
+   {
+      this.message = message;
+   }
+
+
+
+   /*******************************************************************************
+    ** Fluent setter for message
+    *******************************************************************************/
+   public CollectedLogMessage withMessage(String message)
+   {
+      this.message = message;
+      return (this);
+   }
+
+
+
+   /*******************************************************************************
+    ** Getter for exception
+    *******************************************************************************/
+   public Throwable getException()
+   {
+      return (this.exception);
+   }
+
+
+
+   /*******************************************************************************
+    ** Setter for exception
+    *******************************************************************************/
+   public void setException(Throwable exception)
+   {
+      this.exception = exception;
+   }
+
+
+
+   /*******************************************************************************
+    ** Fluent setter for exception
+    *******************************************************************************/
+   public CollectedLogMessage withException(Throwable exception)
+   {
+      this.exception = exception;
+      return (this);
+   }
+
+
+
+   /*******************************************************************************
+    ** Getter for level
+    **
+    *******************************************************************************/
+   public Level getLevel()
+   {
+      return level;
+   }
+
+
+
+   /*******************************************************************************
+    ** Setter for level
+    **
+    *******************************************************************************/
+   public void setLevel(Level level)
+   {
+      this.level = level;
+   }
+
+
+
+   /*******************************************************************************
+    ** Fluent setter for level
+    **
+    *******************************************************************************/
+   public CollectedLogMessage withLevel(Level level)
+   {
+      this.level = level;
+      return (this);
+   }
+
+
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   public JSONObject getMessageAsJSONObject() throws JSONException
+   {
+      return (new JSONObject(getMessage()));
+   }
+}

qqq-backend-core/src/main/java/com/kingsrook/qqq/backend/core/logging/QCollectingLogger.java

@@ -0,0 +1,155 @@
+/*
+ * QQQ - Low-code Application Framework for Engineers.
+ * Copyright (C) 2021-2024.  Kingsrook, LLC
+ * 651 N Broad St Ste 205 # 6917 | Middletown DE 19709 | United States
+ * contact@kingsrook.com
+ * https://github.com/Kingsrook/
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.kingsrook.qqq.backend.core.logging;
+
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Properties;
+import org.apache.logging.log4j.Level;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.Marker;
+import org.apache.logging.log4j.message.Message;
+import org.apache.logging.log4j.message.ObjectMessage;
+import org.apache.logging.log4j.message.SimpleMessageFactory;
+import org.apache.logging.log4j.simple.SimpleLogger;
+import org.apache.logging.log4j.util.PropertiesUtil;
+
+
+/*******************************************************************************
+ ** QQQ log4j implementation, used within a QLogger, to "collect" log messages
+ ** in an internal list - the idea being - for tests, to assert that logs happened.
+ *******************************************************************************/
+public class QCollectingLogger extends SimpleLogger
+{
+   private List<CollectedLogMessage> collectedMessages = new ArrayList<>();
+
+   ///////////////////////////////////////////////////////////////////////////////////////////////////////////
+   // just in case one of these gets activated, and left on, put a limit on how many messages we'll collect //
+   ///////////////////////////////////////////////////////////////////////////////////////////////////////////
+   private int capacity = 100;
+
+   private Logger logger;
+
+
+
+   /*******************************************************************************
+    ** Constructor
+    **
+    *******************************************************************************/
+   public QCollectingLogger(Logger logger)
+   {
+      super(logger.getName(), logger.getLevel(), false, false, true, false, "", new SimpleMessageFactory(), new PropertiesUtil(new Properties()), System.out);
+      this.logger = logger;
+   }
+
+
+
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   @Override
+   public void logMessage(String fqcn, Level level, Marker marker, Message message, Throwable throwable)
+   {
+      ////////////////////////////////////////////
+      // add this log message to our collection //
+      ////////////////////////////////////////////
+      collectedMessages.add(new CollectedLogMessage()
+         .withLevel(level)
+         .withMessage(message.getFormattedMessage())
+         .withException(throwable));
+
+      ////////////////////////////////////////////////////////////////////////////////////////
+      // if we've gone over our capacity, remove the 1st entry until we're back at capacity //
+      ////////////////////////////////////////////////////////////////////////////////////////
+      while(collectedMessages.size() > capacity)
+      {
+         collectedMessages.remove(0);
+      }
+
+      //////////////////////////////////////////////////////////////////////
+      // update the message that we log to indicate that we collected it. //
+      // if it looks like JSON, insert as a name:value pair; else text.   //
+      //////////////////////////////////////////////////////////////////////
+      String formattedMessage = message.getFormattedMessage();
+      String updatedMessage;
+      if(formattedMessage.startsWith("{"))
+      {
+         updatedMessage = """
+            {"collected":true,""" + formattedMessage.substring(1);
+      }
+      else
+      {
+         updatedMessage = "[Collected] " + formattedMessage;
+      }
+      ObjectMessage myMessage = new ObjectMessage(updatedMessage);
+
+      ///////////////////////////////////////////////////////////////////////////////////////
+      // log the message with the original log4j logger, with our slightly updated message //
+      ///////////////////////////////////////////////////////////////////////////////////////
+      logger.logMessage(level, marker, fqcn, null, myMessage, throwable);
+   }
+
+
+
+   /*******************************************************************************
+    ** Setter for logger
+    **
+    *******************************************************************************/
+   public void setLogger(Logger logger)
+   {
+      this.logger = logger;
+   }
+
+
+
+   /*******************************************************************************
+    ** Getter for collectedMessages
+    **
+    *******************************************************************************/
+   public List<CollectedLogMessage> getCollectedMessages()
+   {
+      return collectedMessages;
+   }
+
+
+
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   public void clear()
+   {
+      this.collectedMessages.clear();
+   }
+
+
+
+   /*******************************************************************************
+    ** Setter for capacity
+    **
+    *******************************************************************************/
+   public void setCapacity(int capacity)
+   {
+      this.capacity = capacity;
+   }
+
+}

qqq-backend-core/src/main/java/com/kingsrook/qqq/backend/core/logging/QLogger.java

@@ -119,6 +119,34 @@ public class QLogger
 
 
 
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   public static QCollectingLogger activateCollectingLoggerForClass(Class<?> c)
+   {
+      Logger            loggerFromLogManager = LogManager.getLogger(c);
+      QCollectingLogger collectingLogger     = new QCollectingLogger(loggerFromLogManager);
+
+      QLogger qLogger = getLogger(c);
+      qLogger.setLogger(collectingLogger);
+
+      return collectingLogger;
+   }
+
+
+
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   public static void deactivateCollectingLoggerForClass(Class<?> c)
+   {
+      Logger  loggerFromLogManager = LogManager.getLogger(c);
+      QLogger qLogger              = getLogger(c);
+      qLogger.setLogger(loggerFromLogManager);
+   }
+
+
+
    /*******************************************************************************
     **
     *******************************************************************************/
@@ -518,7 +546,7 @@ public class QLogger
    /*******************************************************************************
     **
     *******************************************************************************/
-   private String makeJsonString(String message, Throwable t, List<LogPair> logPairList)
+   protected String makeJsonString(String message, Throwable t, List<LogPair> logPairList)
    {
       if(logPairList == null)
       {
@@ -620,4 +648,15 @@ public class QLogger
       exceptionList.get(0).setHasLoggedLevel(level);
       return (level);
    }
+
+
+
+   /*******************************************************************************
+    ** Setter for logger
+    **
+    *******************************************************************************/
+   private void setLogger(Logger logger)
+   {
+      this.logger = logger;
+   }
 }

qqq-backend-core/src/test/java/com/kingsrook/qqq/backend/core/logging/QCollectingLoggerTest.java

@@ -0,0 +1,92 @@
+/*
+ * QQQ - Low-code Application Framework for Engineers.
+ * Copyright (C) 2021-2024.  Kingsrook, LLC
+ * 651 N Broad St Ste 205 # 6917 | Middletown DE 19709 | United States
+ * contact@kingsrook.com
+ * https://github.com/Kingsrook/
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.kingsrook.qqq.backend.core.logging;
+
+
+import com.kingsrook.qqq.backend.core.BaseTest;
+import org.apache.logging.log4j.Level;
+import org.junit.jupiter.api.Test;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+
+/*******************************************************************************
+ ** Unit test for QCollectingLogger 
+ *******************************************************************************/
+class QCollectingLoggerTest extends BaseTest
+{
+
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   @Test
+   void test()
+   {
+      ClassThatLogsThings classThatLogsThings = new ClassThatLogsThings();
+      classThatLogsThings.logAnInfo("1");
+
+      QCollectingLogger collectingLogger = QLogger.activateCollectingLoggerForClass(ClassThatLogsThings.class);
+      classThatLogsThings.logAnInfo("2");
+      classThatLogsThings.logAWarn("3");
+      QLogger.deactivateCollectingLoggerForClass(ClassThatLogsThings.class);
+
+      classThatLogsThings.logAWarn("4");
+
+      assertEquals(2, collectingLogger.getCollectedMessages().size());
+
+      assertThat(collectingLogger.getCollectedMessages().get(0).getMessage()).contains("""
+         "message":"2",""");
+      assertEquals("2", collectingLogger.getCollectedMessages().get(0).getMessageAsJSONObject().getString("message"));
+      assertEquals(Level.INFO, collectingLogger.getCollectedMessages().get(0).getLevel());
+
+      assertThat(collectingLogger.getCollectedMessages().get(1).getMessage()).contains("""
+         "message":"3",""");
+      assertEquals(Level.WARN, collectingLogger.getCollectedMessages().get(1).getLevel());
+      assertEquals("3", collectingLogger.getCollectedMessages().get(1).getMessageAsJSONObject().getString("message"));
+   }
+
+
+   /*******************************************************************************
+    **
+    *******************************************************************************/
+   public static class ClassThatLogsThings
+   {
+      private static final QLogger LOG = QLogger.getLogger(ClassThatLogsThings.class);
+
+      /*******************************************************************************
+       **
+       *******************************************************************************/
+      private void logAnInfo(String message)
+      {
+         LOG.info(message);
+      }
+
+      /*******************************************************************************
+       **
+       *******************************************************************************/
+      private void logAWarn(String message)
+      {
+         LOG.warn(message);
+      }
+   }
+
+}