Refactor flint log format

flint-core/src/main/java/org/opensearch/flint/core/logging/CustomLogging.java

@@ -0,0 +1,165 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.flint.core.logging;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.message.Message;
+
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.function.BiConsumer;
+
+/**
+ * CustomLogging provides a structured logging framework that supports various log levels
+ * and formats log messages as JSON. This new log format follows OTEL convention
+ * https://opentelemetry.io/docs/specs/semconv/general/logs/
+ */
+public class CustomLogging {
+    private static final Logger logger = LogManager.getLogger(CustomLogging.class);
+    private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
+
+    private static final String CLIENT_ID;
+    private static final String DOMAIN_NAME;
+    private static final String UNKNOWN = "UNKNOWN";
+
+    /**
+     * Default severity level follows https://opentelemetry.io/docs/specs/otel/logs/data-model/#field-severitynumber
+     */
+    private static final Map<String, Integer> severityLevelMap = Map.of(
+            "TRACE", 1,
+            "DEBUG", 5,
+            "INFO", 9,
+            "WARN", 13,
+            "ERROR", 17,
+            "FATAL", 21
+    );
+    private static final BiConsumer<String, Throwable> defaultLogAction = logger::info;
+    private static final Map<String, BiConsumer<String, Throwable>> logLevelActions = new HashMap<>();
+
+    static {
+        String[] parts = System.getenv().getOrDefault("FLINT_CLUSTER_NAME", UNKNOWN + ":" + UNKNOWN).split(":");
+        CLIENT_ID = parts.length == 2 ? parts[0] : UNKNOWN;
+        DOMAIN_NAME = parts.length == 2 ? parts[1] : UNKNOWN;
+
+        logLevelActions.put("DEBUG", logger::debug);
+        logLevelActions.put("INFO", logger::info);
+        logLevelActions.put("WARN", logger::warn);
+        logLevelActions.put("ERROR", logger::error);
+        logLevelActions.put("FATAL", logger::fatal);
+    }
+
+    private static int getSeverityNumber(String level) {
+        return severityLevelMap.getOrDefault(level, 0);
+    }
+
+    private static String convertToJson(Map<String, Object> logEventMap) {
+        try {
+            return OBJECT_MAPPER.writeValueAsString(logEventMap);
+        } catch (JsonProcessingException e) {
+            System.err.println("Error serializing log event to JSON: " + e.getMessage());
+            return "{\"Error\":\"Error serializing log event\"}";
+        }
+    }
+
+    /**
+     * Constructs a log event map containing log details such as timestamp, severity,
+     * message body, and custom attributes including domainName and clientId.
+     *
+     * @param level     The severity level of the log.
+     * @param content   The main content of the log message.
+     * @param throwable An optional Throwable associated with log messages for error levels.
+     * @return A map representation of the log event.
+     */
+    protected static Map<String, Object> constructLogEventMap(String level, Object content, Throwable throwable) {
+        if (content == null) {
+            throw new IllegalArgumentException("Log message must not be null");
+        }
+
+        Map<String, Object> logEventMap = new LinkedHashMap<>();
+        Map<String, Object> body = new LinkedHashMap<>();
+        constructMessageBody(content, body);
+
+        Map<String, Object> attributes = new LinkedHashMap<>();
+        attributes.put("domainName", DOMAIN_NAME);
+        attributes.put("clientId", CLIENT_ID);
+
+        if (throwable != null) {
+            attributes.put("exception.type", throwable.getClass().getName());
+            attributes.put("exception.message", throwable.getMessage());
+        }
+
+        logEventMap.put("timestamp", System.currentTimeMillis());
+        logEventMap.put("severityText", level);
+        logEventMap.put("severityNumber", getSeverityNumber(level));
+        logEventMap.put("body", body);
+        logEventMap.put("attributes", attributes);
+
+        return logEventMap;
+    }
+
+    private static void constructMessageBody(Object content, Map<String, Object> body) {
+        if (content instanceof Message) {
+            Message message = (Message) content;
+            body.put("message", message.getFormattedMessage());
+            if (content instanceof OperationMessage && message.getParameters().length > 0) {
+                body.put("statusCode", message.getParameters()[0]);
+            }
+        } else {
+            body.put("message", content.toString());
+        }
+    }
+
+    /**
+     * Logs a message with the specified severity level, message content, and an optional throwable.
+     *
+     * @param level     The severity level of the log.
+     * @param content   The content of the log message.
+     * @param throwable An optional Throwable for logging errors or exceptions.
+     */
+    private static void log(String level, Object content, Throwable throwable) {
+        Map<String, Object> logEventMap = constructLogEventMap(level, content, throwable);
+        String jsonMessage = convertToJson(logEventMap);
+        logLevelActions.getOrDefault(level, defaultLogAction).accept(jsonMessage, throwable);
+    }
+
+    // Public logging methods for various severity levels.
+
+    public static void logDebug(Object message) {
+        log("DEBUG", message, null);
+    }
+
+    public static void logInfo(Object message) {
+        log("INFO", message, null);
+    }
+
+    public static void logWarning(Object message) {
+        log("WARN", message, null);
+    }
+
+    public static void logWarning(Object message, Throwable e) {
+        log("WARN", message, e);
+    }
+
+    public static void logError(Object message) {
+        log("ERROR", message, null);
+    }
+
+    public static void logError(Object message, Throwable throwable) {
+        log("ERROR", message, throwable);
+    }
+
+    public static void logFatal(Object message) {
+        log("FATAL", message, null);
+    }
+
+    public static void logFatal(Object message, Throwable throwable) {
+        log("FATAL", message, throwable);
+    }
+}

flint-core/src/main/java/org/opensearch/flint/core/logging/OperationMessage.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.flint.core.logging;
+
+import org.apache.logging.log4j.message.Message;
+
+/**
+ * Represents an operation message with optional status code for logging purposes.
+ */
+public final class OperationMessage implements Message {
+    private final String message;
+    private final Integer statusCode;
+
+    /**
+     * Constructs an OperationMessage without a status code.
+     *
+     * @param message The message content.
+     */
+    public OperationMessage(String message) {
+        this(message, null);
+    }
+
+    /**
+     * Constructs an OperationMessage with a message and an optional status code.
+     *
+     * @param message The message content.
+     * @param statusCode An optional status code, can be null.
+     */
+    public OperationMessage(String message, Integer statusCode) {
+        this.message = message;
+        this.statusCode = statusCode;
+    }
+
+    @Override
+    public String getFormattedMessage() {
+        return message;
+    }
+
+    @Override
+    public String getFormat() {
+        return message;
+    }
+
+    @Override
+    public Object[] getParameters() {
+        // Always return an array, even if empty, to avoid null checks on the consuming side
+        return statusCode != null ? new Object[]{statusCode} : new Object[]{};
+    }
+
+    @Override
+    public Throwable getThrowable() {
+        // This implementation does not support Throwable directly
+        return null;
+    }
+}

flint-core/src/main/java/org/opensearch/flint/core/metrics/reporter/DimensionedCloudWatchReporter.java

@@ -137,7 +137,6 @@ public void report(final SortedMap<String, Gauge> gauges,
                        final SortedMap<String, Histogram> histograms,
                        final SortedMap<String, Meter> meters,
                        final SortedMap<String, Timer> timers) {
-
         if (builder.withDryRun) {
             LOGGER.warn("** Reporter is running in 'DRY RUN' mode **");
         }

flint-core/src/test/java/org/opensearch/flint/core/logging/CustomLoggingTest.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.flint.core.logging;
+
+import org.apache.logging.log4j.message.SimpleMessage;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Map;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+@RunWith(Parameterized.class)
+public class CustomLoggingTest {
+    private static final String testMsg = "Test message";
+
+    @Parameterized.Parameter(0)
+    public Object content;
+
+    @Parameterized.Parameter(1)
+    public String expectedMessage;
+
+    @Parameterized.Parameter(2)
+    public Object expectedStatusCode;
+
+    @Parameterized.Parameter(3)
+    public String severityLevel;
+
+    @Parameterized.Parameter(4)
+    public Throwable throwable;
+
+    @Parameterized.Parameters(name = "{index}: Test with content={0}, expectedMessage={1}, expectedStatusCode={2}, severityLevel={3}, throwable={4}")
+    public static Collection<Object[]> data() {
+        return Arrays.asList(new Object[][]{
+                {testMsg, testMsg, null, "INFO", null},
+                {new SimpleMessage(testMsg), testMsg, null, "DEBUG", null},
+                {new OperationMessage(testMsg, 403), testMsg, 403, "ERROR", new RuntimeException("Test Exception")},
+                {testMsg, testMsg, null, "UNDEFINED_LEVEL", null}, // Test with an undefined severity level
+                {new SimpleMessage(testMsg), testMsg, null, "INFO", new Exception("New Exception")},
+                {testMsg, testMsg, null, "WARN", null},
+                {"", "", null, "INFO", null},
+                {new SimpleMessage(testMsg), testMsg, null, "FATAL", new Error("Critical Error")},
+        });
+    }
+
+    @Test
+    public void testConstructLogEventMap() {
+        Map<String, Object> logEventMap = CustomLogging.constructLogEventMap(severityLevel, content, throwable);
+
+        assertEquals("Incorrect severity text", severityLevel, logEventMap.get("severityText"));
+        assertTrue("Timestamp should be present and greater than 0", (Long)logEventMap.get("timestamp") > 0);
+        assertNotNull("Severity number should not be null", logEventMap.get("severityNumber"));
+
+        Map<String, Object> body = (Map<String, Object>) logEventMap.get("body");
+        assertEquals("Expected message value not found", expectedMessage, body.get("message"));
+        if (expectedStatusCode != null) {
+            assertEquals("Expected status code not found", expectedStatusCode, body.get("statusCode"));
+        } else {
+            assertNull("Status code should be null", body.get("statusCode"));
+        }
+
+        if (throwable != null) {
+            Map<String, Object> attributes = (Map<String, Object>) logEventMap.get("attributes");
+            assertEquals("Exception type should match", throwable.getClass().getName(), attributes.get("exception.type"));
+            assertEquals("Exception message should match", throwable.getMessage(), attributes.get("exception.message"));
+        }
+    }
+}

flint-core/src/test/java/org/opensearch/flint/core/metrics/reporter/DimensionUtilsTest.java

@@ -7,7 +7,6 @@
 
 import org.apache.spark.SparkConf;
 import org.apache.spark.SparkEnv;
-import org.apache.spark.metrics.source.FlintMetricSource;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 import static org.junit.jupiter.api.Assertions.assertEquals;