chore: docs and javadocs update

Author: Pankaj Agrawal

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

@@ -1,11 +1,34 @@
 package software.amazon.lambda.powertools.logging;
 
+/**
+ * Supported Event types from which Correlation ID can be extracted
+ */
 public enum CorrelationIdPath {
+    /**
+     * To use when function is expecting API Gateway Rest API Request event
+     */
     API_GATEWAY_REST("/requestContext/requestId"),
+    /**
+     * To use when function is expecting API Gateway HTTP API Request event
+     */
     API_GATEWAY_HTTP("/requestContext/requestId"),
+    /**
+     * To use when function is expecting Application Load balancer Request event
+     */
     APPLICATION_LOAD_BALANCER("/headers/x-amzn-trace-id"),
+    /**
+     * To use when function is expecting Event Bridge Request event
+     */
     EVENT_BRIDGE("/id"),
+    /**
+     * To use when function is expecting any of the supported event types to automatically
+     * extract the correlation id. When running in this mode, if its unable to find any of the
+     * supported types, capturing of correlation id will not be done.
+     */
     AUTO_DETECT(""),
+    /**
+     * To use when you dont want to extract correlation id.
+     */
     DISABLED("");
 
     private final String path;

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

@@ -70,5 +70,8 @@
 
     double samplingRate() default 0;
 
+    /**
+     * Type of Event from where to extract correlation id from.
+     */
     CorrelationIdPath correlationIdPath() default DISABLED;
 }

powertools-logging/src/main/java/software/amazon/lambda/powertools/logging/internal/LambdaLoggingAspect.java

@@ -210,7 +210,13 @@ private void setCorrelationIdFromNode(CorrelationIdPath correlationIdPath, Proce
             autoDetect(pjp, jsonNode);
         } else {
             JsonNode node = jsonNode.at(JsonPointer.compile(correlationIdPath.getPath()));
-            LoggingUtils.setCorrelationId(node.asText());
+
+            String asText = node.asText();
+            if (null != asText && !asText.isEmpty()) {
+                LoggingUtils.setCorrelationId(asText);
+            } else {
+                logger(pjp).debug("Unable to extract any correlation id. Is your function expecting supported event type?");
+            }
         }
     }