logging module independent from implementation, based on slf4j

Author: jeromevdl

powertools-logging/pom.xml

@@ -3,16 +3,15 @@
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
-
-    <artifactId>powertools-logging</artifactId>
-    <packaging>jar</packaging>
-
     <parent>
         <artifactId>powertools-parent</artifactId>
         <groupId>software.amazon.lambda</groupId>
         <version>1.12.3</version>
     </parent>
 
+    <artifactId>powertools-logging</artifactId>
+    <packaging>jar</packaging>
+
     <name>AWS Lambda Powertools for Java library Logging</name>
     <description>
         A suite of utilities for AWS Lambda Functions that makes tracing with AWS X-Ray, structured logging and creating custom metrics asynchronously easier.
@@ -54,24 +53,8 @@
             <artifactId>jackson-databind</artifactId>
         </dependency>
         <dependency>
-            <groupId>org.apache.logging.log4j</groupId>
-            <artifactId>log4j-layout-template-json</artifactId>
-        </dependency>
-        <dependency>
-            <groupId>org.apache.logging.log4j</groupId>
-            <artifactId>log4j-core</artifactId>
-        </dependency>
-        <dependency>
-            <groupId>org.apache.logging.log4j</groupId>
-            <artifactId>log4j-slf4j-impl</artifactId>
-        </dependency>
-        <dependency>
-            <groupId>org.apache.logging.log4j</groupId>
-            <artifactId>log4j-api</artifactId>
-        </dependency>
-        <dependency>
-            <groupId>org.aspectj</groupId>
-            <artifactId>aspectjrt</artifactId>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
         </dependency>
 
         <!-- Test dependencies -->
@@ -126,5 +109,4 @@
             <scope>test</scope>
         </dependency>
     </dependencies>
-
 </project>

powertools-logging/src/main/java/software/amazon/lambda/powertools/logging/Logging.java

@@ -42,9 +42,9 @@
  * <p>By default {@code Logging} will also create keys for:</p>
  *
  * <ul>
- *     <li>coldStart - True if this is the first invocation of this Lambda execution environment; else False</li>
+ *     <li>cold_start - True if this is the first invocation of this Lambda execution environment; else False</li>
  *     <li>service - The value of the 'POWER_TOOLS_SERVICE_NAME' environment variable or 'service_undefined'</li>
- *     <li>samplingRate - The value of the 'POWERTOOLS_LOGGER_SAMPLE_RATE' environment variable or value of samplingRate field or 0.
+ *     <li>sampling_rate - The value of the 'POWERTOOLS_LOGGER_SAMPLE_RATE' environment variable or value of sampling_rate field or 0.
  *     Valid value is from 0.0 to 1.0. Value outside this range is silently ignored.</li>
  * </ul>
  *

powertools-logging/src/main/java/software/amazon/lambda/powertools/logging/LoggingUtils.java

@@ -13,12 +13,11 @@
  */
 package software.amazon.lambda.powertools.logging;
 
-import java.util.Map;
-
 import com.fasterxml.jackson.databind.ObjectMapper;
-import org.apache.logging.log4j.ThreadContext;
+import org.slf4j.MDC;
 
-import static java.util.Arrays.asList;
+import java.util.Arrays;
+import java.util.Map;
 
 /**
  * A class of helper functions to add additional functionality to Logging.
@@ -39,7 +38,7 @@ private LoggingUtils() {
      * @param value The value to be logged
      */
     public static void appendKey(String key, String value) {
-        ThreadContext.put(key, value);
+        MDC.put(key, value);
     }
 
 
@@ -51,7 +50,7 @@ public static void appendKey(String key, String value) {
      * @param customKeys Map of custom keys values to be appended to logs
      */
     public static void appendKeys(Map<String, String> customKeys) {
-        ThreadContext.putAll(customKeys);
+        customKeys.forEach(MDC::put);
     }
 
     /**
@@ -60,7 +59,7 @@ public static void appendKeys(Map<String, String> customKeys) {
      * @param customKey The name of the key to be logged
      */
     public static void removeKey(String customKey) {
-        ThreadContext.remove(customKey);
+        MDC.remove(customKey);
     }
 
 
@@ -70,7 +69,7 @@ public static void removeKey(String customKey) {
      * @param keys Map of custom keys values to be appended to logs
      */
     public static void removeKeys(String... keys) {
-        ThreadContext.removeAll(asList(keys));
+        Arrays.stream(keys).forEach(MDC::remove);
     }
 
     /**
@@ -79,7 +78,7 @@ public static void removeKeys(String... keys) {
      * @param value The value of the correlation id
      */
     public static void setCorrelationId(String value) {
-        ThreadContext.put("correlation_id", value);
+        MDC.put("correlation_id", value);
     }
 
     /**