feat(logging): add support for key-value pairs in LambdaJsonEncoder

Author: cmtjk

powertools-logging/powertools-logging-logback/src/main/java/software/amazon/lambda/powertools/logging/logback/JsonUtils.java

@@ -73,6 +73,12 @@ static void serializeMDCEntry(Map.Entry<String, String> entry, JsonSerializer se
         }
     }
 
+    static void serializeKVPEntry(String key, Object value, JsonSerializer serializer) {
+        serializer.writeRaw(',');
+        serializer.writeFieldName(key);
+        serializer.writeObject(value);
+    }
+
     static void serializeArguments(ILoggingEvent event, JsonSerializer serializer) throws IOException {
         Object[] arguments = event.getArgumentArray();
         if (arguments != null) {

powertools-logging/powertools-logging-logback/src/main/java/software/amazon/lambda/powertools/logging/logback/LambdaJsonEncoder.java

@@ -15,10 +15,7 @@
 package software.amazon.lambda.powertools.logging.logback;
 
 import static java.nio.charset.StandardCharsets.UTF_8;
-import static software.amazon.lambda.powertools.logging.logback.JsonUtils.serializeArguments;
-import static software.amazon.lambda.powertools.logging.logback.JsonUtils.serializeMDCEntries;
-import static software.amazon.lambda.powertools.logging.logback.JsonUtils.serializeMDCEntry;
-import static software.amazon.lambda.powertools.logging.logback.JsonUtils.serializeTimestamp;
+import static software.amazon.lambda.powertools.logging.logback.JsonUtils.*;
 
 import ch.qos.logback.classic.pattern.ThrowableHandlingConverter;
 import ch.qos.logback.classic.pattern.ThrowableProxyConverter;
@@ -27,10 +24,8 @@
 import ch.qos.logback.classic.spi.ThrowableProxy;
 import ch.qos.logback.core.encoder.EncoderBase;
 import java.io.IOException;
-import java.util.Arrays;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.TreeMap;
+import java.util.*;
+
 import software.amazon.lambda.powertools.logging.internal.JsonSerializer;
 import software.amazon.lambda.powertools.logging.internal.PowertoolsLoggedFields;
 
@@ -88,6 +83,8 @@ public byte[] encode(ILoggingEvent event) {
 
             serializeMDCEntries(sortedMap, serializer);
 
+            serializeKeyValuePairs(event, serializer);
+
             serializeArguments(event, serializer);
 
             serializeThreadInfo(event, serializer);
@@ -104,6 +101,13 @@ public byte[] encode(ILoggingEvent event) {
         return builder.toString().getBytes(UTF_8);
     }
 
+    private void serializeKeyValuePairs(ILoggingEvent event, JsonSerializer serializer) {
+        Optional.ofNullable(event.getKeyValuePairs())
+            .orElse(Collections.emptyList()).stream()
+            .filter(Objects::nonNull)
+            .forEach(kvp -> serializeKVPEntry(String.valueOf(kvp.key), kvp.value, serializer));
+    }
+
     private void serializeThreadInfo(ILoggingEvent event, JsonSerializer serializer) {
         if (includeThreadInfo) {
             if (event.getThreadName() != null) {

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

@@ -40,6 +40,7 @@
 import java.nio.file.StandardOpenOption;
 import java.text.SimpleDateFormat;
 import java.util.Arrays;
+import java.util.List;
 import java.util.Collections;
 import java.util.Date;
 import java.util.TimeZone;
@@ -50,6 +51,7 @@
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Order;
 import org.junit.jupiter.api.Test;
+import org.slf4j.event.KeyValuePair;
 import software.amazon.lambda.powertools.common.stubs.TestLambdaContext;
 import org.slf4j.LoggerFactory;
 import org.slf4j.MDC;
@@ -442,4 +444,61 @@ void shouldLogException() {
                 .contains("\"stack\":\"java.lang.IllegalStateException: Unexpected value\\n");
     }
 
+    @Test
+    void shouldLogKeyValuePairs() {
+        // GIVEN
+        LambdaJsonEncoder encoder = new LambdaJsonEncoder();
+        encoder.start();
+
+        Object[] arguments = {
+            "argument_01",
+            StructuredArguments.entry("structured_argument_01_retain", "retained"),
+            StructuredArguments.entry("structured_argument_02_overwrite", "to_be_overwritten")
+        };
+        LoggingEvent keyValuePairsLoggingEvent = new LoggingEvent("fqcn", logger, Level.INFO, "Key Value Pairs Test with argument: {}",
+                null, arguments);
+
+        MDC.put("mdc_01_retain", "retained");
+        MDC.put("mdc_02_overwrite", "to_be_overwritten");
+
+        keyValuePairsLoggingEvent.setKeyValuePairs(List.of(
+                new KeyValuePair("key_01_string", "value_01"),
+                new KeyValuePair("key_02_numeric", 2),
+                new KeyValuePair("key_03_decimal", 2.333),
+                new KeyValuePair("key_04_null", null),
+                new KeyValuePair("", "value_05_empty_key"),
+                new KeyValuePair(null, "value_06_null_key"),
+                new KeyValuePair("key_07_boolean_true", true),
+                new KeyValuePair("key_08_boolean_false", false),
+                new KeyValuePair("mdc_02_overwrite", "overwritten_by_kvp"),
+                new KeyValuePair("structured_argument_02_overwrite", "overwritten_by_kvp")
+                ));
+
+        // WHEN
+        byte[] encoded = encoder.encode(keyValuePairsLoggingEvent);
+        String result = new String(encoded, StandardCharsets.UTF_8);
+
+        // THEN
+        assertThat(result)
+                // Arguments
+                .contains("Key Value Pairs Test with argument: argument_01")
+                .contains("\"structured_argument_01_retain\":\"retained\"")
+                // .doesNotContain("\"structured_argument_02_overwrite\":\"to_be_overwritten\"") TODO: Deduplication not implemented vor Arguments
+                // MDC
+                .contains("\"mdc_01_retain\":\"retained\"")
+                // .doesNotContain("\"mdc_02_overwrite\":\"to_be_overwritten\"") TODO: Deduplication not implemented vor Arguments
+                // Key Value Pairs
+                .contains("\"key_01_string\":\"value_01\"")
+                .contains("\"key_02_numeric\":2")
+                .contains("\"key_03_decimal\":2.333")
+                .contains("\"key_04_null\":null")
+                .contains("\"\":\"value_05_empty_key\"")
+                .contains("\"null\":\"value_06_null_key\"")
+                .contains("\"key_07_boolean_true\":true")
+                .contains("\"key_08_boolean_false\":false")
+                .contains("\"mdc_02_overwrite\":\"overwritten_by_kvp\"")
+                .contains("\"structured_argument_02_overwrite\":\"overwritten_by_kvp\"")
+        ;
+    }
+
 }