LC-416 added json logging for elk

lucille-core/pom.xml

@@ -58,7 +58,12 @@
       </exclusions>
     </dependency>
 
-
+  <!-- dependency to allow json logging for log4j -->
+  <dependency>
+      <groupId>org.apache.logging.log4j</groupId>
+      <artifactId>log4j-layout-template-json</artifactId>
+      <version>2.22.1</version>
+  </dependency>
 
     <dependency>
       <groupId>org.apache.kafka</groupId>

lucille-core/src/main/java/com/kmwllc/lucille/core/Stage.java

@@ -13,7 +13,6 @@
 import java.util.*;
 import java.util.function.Predicate;
 import java.util.stream.Collectors;
-import java.util.stream.Stream;
 
 /**
  * An operation that can be performed on a Document.<br>

lucille-core/src/main/resources/log4j2.xml

@@ -18,13 +18,21 @@
             </Policies>
             <DefaultRolloverStrategy max="4" />
         </RollingFile>
+        <RollingFile name="file-json" fileName="./log/com.kmwllc.lucille-json.log" filePattern="./log/com.kmwllc.lucille-json-%i.log">
+            <JsonTemplateLayout eventTemplateUri="classpath:EcsLayout.json"/>
+            <Policies>
+                <SizeBasedTriggeringPolicy size="10 KB" />
+            </Policies>
+            <DefaultRolloverStrategy max="20" />
+        </RollingFile>
     </Appenders>
     <Loggers>
+<!--    NOTE: Replace the "file" AppenderRef with "file-json" if you would like to enable json logging.  -->
+<!--    You can also add an appender like '<AppenderRef ref="file-json" />' to the loggers to get both non-json AND json logging. -->
         <Root level="INFO">
             <AppenderRef ref="console" />
             <AppenderRef ref="file" />
         </Root>
-
         <Logger name="com.kmwllc.lucille.core.Heartbeat" level="INFO" additivity="false">
             <AppenderRef ref="heartbeat" />
         </Logger>

lucille-core/src/test/resources/EcsLayout.json

@@ -0,0 +1,49 @@
+{
+  "@timestamp": {
+    "$resolver": "timestamp",
+    "pattern": {
+      "format": "yy/MM/dd'T'HH:mm:ss'Z'",
+      "timeZone": "UTC"
+    }
+  },
+  "ecs.version": "1.2.0",
+  "log.level": {
+    "$resolver": "level",
+    "field": "name"
+  },
+  "message": {
+    "$resolver": "message",
+    "stringified": true
+  },
+  "process.thread.name": {
+    "$resolver": "thread",
+    "field": "name"
+  },
+  "log.logger": {
+    "$resolver": "logger",
+    "field": "name"
+  },
+  "labels": {
+    "$resolver": "mdc",
+    "flatten": true,
+    "stringified": true
+  },
+  "tags": {
+    "$resolver": "ndc"
+  },
+  "error.type": {
+    "$resolver": "exception",
+    "field": "className"
+  },
+  "error.message": {
+    "$resolver": "exception",
+    "field": "message"
+  },
+  "error.stack_trace": {
+    "$resolver": "exception",
+    "field": "stackTrace",
+    "stackTrace": {
+      "stringified": true
+    }
+  }
+}