feat: ability to override object mapper used for logging event

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

@@ -15,6 +15,7 @@
 
 import java.util.Map;
 
+import com.fasterxml.jackson.databind.ObjectMapper;
 import org.apache.logging.log4j.ThreadContext;
 
 /**
@@ -23,6 +24,7 @@
  * {@see Logging}
  */
 public final class LoggingUtils {
+    private static ObjectMapper objectMapper = new ObjectMapper();
 
     private LoggingUtils() {
     }
@@ -48,4 +50,18 @@ public static void appendKey(String key, String value) {
     public static void appendKeys(Map<String, String> customKeys) {
         ThreadContext.putAll(customKeys);
     }
+
+    /**
+     * Sets the instance of ObjectMapper object which is used for serialising event when
+     * {@code @Logging(logEvent = true)}.
+     *
+     * @param objectMapper Custom implementation of object mapper to be used for logging serialised event
+     */
+    public static void defaultObjectMapper(ObjectMapper objectMapper) {
+        LoggingUtils.objectMapper = objectMapper;
+    }
+
+    public static ObjectMapper objectMapper() {
+        return objectMapper;
+    }
 }

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

@@ -24,7 +24,6 @@
 import java.util.Random;
 
 import com.fasterxml.jackson.core.JsonProcessingException;
-import com.fasterxml.jackson.databind.ObjectMapper;
 import org.apache.logging.log4j.Level;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -50,12 +49,12 @@
 import static software.amazon.lambda.powertools.core.internal.LambdaHandlerProcessor.serviceName;
 import static software.amazon.lambda.powertools.logging.LoggingUtils.appendKey;
 import static software.amazon.lambda.powertools.logging.LoggingUtils.appendKeys;
+import static software.amazon.lambda.powertools.logging.LoggingUtils.objectMapper;
 import static software.amazon.lambda.powertools.logging.internal.SystemWrapper.getenv;
 
 @Aspect
 public final class LambdaLoggingAspect {
     private static final Logger LOG = LogManager.getLogger(LambdaLoggingAspect.class);
-    private static final ObjectMapper MAPPER = new ObjectMapper();
     private static final Random SAMPLER = new Random();
 
     private static final String LOG_LEVEL = System.getenv("LOG_LEVEL");
@@ -176,7 +175,7 @@ private Object[] logFromInputStream(final ProceedingJoinPoint pjp) {
 
             Logger log = logger(pjp);
 
-            asJson(pjp, MAPPER.readValue(bytes, Map.class))
+            asJson(pjp, objectMapper().readValue(bytes, Map.class))
                     .ifPresent(log::info);
 
         } catch (IOException e) {
@@ -190,7 +189,7 @@ private Object[] logFromInputStream(final ProceedingJoinPoint pjp) {
     private Optional<String> asJson(final ProceedingJoinPoint pjp,
                                     final Object target) {
         try {
-            return ofNullable(MAPPER.writeValueAsString(target));
+            return ofNullable(objectMapper().writeValueAsString(target));
         } catch (JsonProcessingException e) {
             logger(pjp).error("Failed logging event of type {}", target.getClass(), e);
             return empty();

powertools-logging/src/test/java/software/amazon/lambda/powertools/logging/handlers/PowerToolLogEventEnabledWithCustomMapper.java

@@ -0,0 +1,49 @@
+package software.amazon.lambda.powertools.logging.handlers;
+
+import java.io.IOException;
+
+import com.amazonaws.services.lambda.runtime.Context;
+import com.amazonaws.services.lambda.runtime.RequestHandler;
+import com.amazonaws.services.lambda.runtime.events.models.s3.S3EventNotification;
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import com.fasterxml.jackson.databind.module.SimpleModule;
+import com.fasterxml.jackson.databind.ser.std.StdSerializer;
+import software.amazon.lambda.powertools.logging.Logging;
+import software.amazon.lambda.powertools.logging.LoggingUtils;
+
+public class PowerToolLogEventEnabledWithCustomMapper implements RequestHandler<S3EventNotification, Object> {
+
+    static {
+        ObjectMapper objectMapper = new ObjectMapper();
+        SimpleModule module = new SimpleModule();
+        module.addSerializer(S3EventNotification.class, new S3EventNotificationSerializer());
+        objectMapper.registerModule(module);
+        LoggingUtils.defaultObjectMapper(objectMapper);
+    }
+
+    @Logging(logEvent = true)
+    @Override
+    public Object handleRequest(S3EventNotification input, Context context) {
+        return null;
+    }
+
+    static class S3EventNotificationSerializer extends StdSerializer<S3EventNotification> {
+
+        public S3EventNotificationSerializer() {
+            this(null);
+        }
+
+        public S3EventNotificationSerializer(Class<S3EventNotification> t) {
+            super(t);
+        }
+
+        @Override
+        public void serialize(S3EventNotification o, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
+            jsonGenerator.writeStartObject();
+            jsonGenerator.writeStringField("eventSource", o.getRecords().get(0).getEventSource());
+            jsonGenerator.writeEndObject();
+        }
+    }
+}

powertools-logging/src/test/java/software/amazon/lambda/powertools/logging/internal/LambdaLoggingAspectTest.java

@@ -47,6 +47,7 @@
 import software.amazon.lambda.powertools.logging.handlers.PowerToolDisabledForStream;
 import software.amazon.lambda.powertools.logging.handlers.PowerToolLogEventEnabled;
 import software.amazon.lambda.powertools.logging.handlers.PowerToolLogEventEnabledForStream;
+import software.amazon.lambda.powertools.logging.handlers.PowerToolLogEventEnabledWithCustomMapper;
 
 import static com.amazonaws.services.lambda.runtime.events.models.s3.S3EventNotification.RequestParametersEntity;
 import static com.amazonaws.services.lambda.runtime.events.models.s3.S3EventNotification.ResponseElementsEntity;
@@ -183,6 +184,23 @@ void shouldLogEventForHandler() throws IOException, JSONException {
         assertEquals(expectEvent, event, false);
     }
 
+    @Test
+    void shouldLogEventForHandlerWithOverriddenObjectMapper() throws IOException, JSONException {
+        RequestHandler<S3EventNotification, Object> handler = new PowerToolLogEventEnabledWithCustomMapper();
+        S3EventNotification s3EventNotification = s3EventNotification();
+
+        handler.handleRequest(s3EventNotification, context);
+
+        Map<String, Object> log = parseToMap(Files.lines(Paths.get("target/logfile.json")).collect(joining()));
+
+        String event = (String) log.get("message");
+
+        String expectEvent = new BufferedReader(new InputStreamReader(this.getClass().getResourceAsStream("/customizedLogEvent.json")))
+                .lines().collect(joining("\n"));
+
+        assertEquals(expectEvent, event, false);
+    }
+
     @Test
     void shouldLogEventForStreamAndLambdaStreamIsValid() throws IOException, JSONException {
         requestStreamHandler = new PowerToolLogEventEnabledForStream();

powertools-logging/src/test/resources/customizedLogEvent.json

@@ -0,0 +1,3 @@
+{
+  "eventSource": "aws:s3"
+}