Add OpenSearch metrics

build.sbt

@@ -67,7 +67,8 @@ lazy val flintCore = (project in file("flint-core"))
       "org.scalatest" %% "scalatest-flatspec" % "3.2.15" % "test",
       "org.scalatestplus" %% "mockito-4-6" % "3.2.15.0" % "test",
       "com.stephenn" %% "scalatest-json-jsonassert" % "0.2.5" % "test",
-      "org.mockito" % "mockito-core" % "2.23.0" % "test",
+      "org.mockito" % "mockito-core" % "4.6.1" % "test",
+      "org.mockito" % "mockito-inline" % "4.6.1" % "test",
       "org.mockito" % "mockito-junit-jupiter" % "3.12.4" % "test",
       "org.junit.jupiter" % "junit-jupiter-api" % "5.9.0" % "test",
       "org.junit.jupiter" % "junit-jupiter-engine" % "5.9.0" % "test",

flint-core/src/main/java/org/opensearch/flint/core/IRestHighLevelClient.java

@@ -0,0 +1,62 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.flint.core;
+
+import org.opensearch.action.bulk.BulkRequest;
+import org.opensearch.action.bulk.BulkResponse;
+import org.opensearch.action.delete.DeleteRequest;
+import org.opensearch.action.delete.DeleteResponse;
+import org.opensearch.action.get.GetRequest;
+import org.opensearch.action.get.GetResponse;
+import org.opensearch.action.index.IndexRequest;
+import org.opensearch.action.index.IndexResponse;
+import org.opensearch.action.search.ClearScrollRequest;
+import org.opensearch.action.search.ClearScrollResponse;
+import org.opensearch.action.search.SearchRequest;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.action.search.SearchScrollRequest;
+import org.opensearch.action.update.UpdateRequest;
+import org.opensearch.action.DocWriteResponse;
+import org.opensearch.client.indices.CreateIndexRequest;
+import org.opensearch.client.indices.CreateIndexResponse;
+import org.opensearch.client.indices.GetIndexRequest;
+import org.opensearch.client.indices.GetIndexResponse;
+import org.opensearch.action.admin.indices.delete.DeleteIndexRequest;
+import org.opensearch.client.RequestOptions;
+
+import java.io.Closeable;
+import java.io.IOException;
+
+/**
+ * Interface for wrapping the OpenSearch High Level REST Client with additional functionality,
+ * such as metrics tracking.
+ */
+public interface IRestHighLevelClient extends Closeable {
+
+    BulkResponse bulk(BulkRequest bulkRequest, RequestOptions options) throws IOException;
+
+    ClearScrollResponse clearScroll(ClearScrollRequest clearScrollRequest, RequestOptions options) throws IOException;
+
+    CreateIndexResponse createIndex(CreateIndexRequest createIndexRequest, RequestOptions options) throws IOException;
+
+    void deleteIndex(DeleteIndexRequest deleteIndexRequest, RequestOptions options) throws IOException;
+
+    DeleteResponse delete(DeleteRequest deleteRequest, RequestOptions options) throws IOException;
+
+    GetResponse get(GetRequest getRequest, RequestOptions options) throws IOException;
+
+    GetIndexResponse getIndex(GetIndexRequest getIndexRequest, RequestOptions options) throws IOException;
+
+    IndexResponse index(IndexRequest indexRequest, RequestOptions options) throws IOException;
+
+    Boolean isIndexExists(GetIndexRequest getIndexRequest, RequestOptions options) throws IOException;
+
+    SearchResponse search(SearchRequest searchRequest, RequestOptions options) throws IOException;
+
+    SearchResponse scroll(SearchScrollRequest searchScrollRequest, RequestOptions options) throws IOException;
+
+    DocWriteResponse update(UpdateRequest updateRequest, RequestOptions options) throws IOException;
+}

flint-core/src/main/java/org/opensearch/flint/core/RestHighLevelClientWrapper.java

@@ -0,0 +1,165 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.flint.core;
+
+import org.opensearch.action.admin.indices.delete.DeleteIndexRequest;
+import org.opensearch.action.bulk.BulkRequest;
+import org.opensearch.action.bulk.BulkResponse;
+import org.opensearch.action.delete.DeleteRequest;
+import org.opensearch.action.delete.DeleteResponse;
+import org.opensearch.action.get.GetRequest;
+import org.opensearch.action.get.GetResponse;
+import org.opensearch.action.index.IndexRequest;
+import org.opensearch.action.index.IndexResponse;
+import org.opensearch.action.search.ClearScrollRequest;
+import org.opensearch.action.search.ClearScrollResponse;
+import org.opensearch.action.search.SearchRequest;
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.action.search.SearchScrollRequest;
+import org.opensearch.action.update.UpdateRequest;
+import org.opensearch.OpenSearchException;
+import org.opensearch.action.update.UpdateResponse;
+import org.opensearch.client.RequestOptions;
+import org.opensearch.client.RestHighLevelClient;
+import org.opensearch.client.indices.CreateIndexRequest;
+import org.opensearch.client.indices.CreateIndexResponse;
+import org.opensearch.client.indices.GetIndexRequest;
+import org.opensearch.client.indices.GetIndexResponse;
+import org.opensearch.flint.core.metrics.MetricsUtil;
+
+import java.io.Closeable;
+import java.io.IOException;
+
+import static org.opensearch.flint.core.metrics.MetricConstants.*;
+
+/**
+ * A wrapper class for RestHighLevelClient to facilitate OpenSearch operations
+ * with integrated metrics tracking.
+ */
+public class RestHighLevelClientWrapper implements IRestHighLevelClient {
+    private final RestHighLevelClient client;
+
+    /**
+     * Constructs a new RestHighLevelClientWrapper.
+     *
+     * @param client the RestHighLevelClient instance to wrap
+     */
+    public RestHighLevelClientWrapper(RestHighLevelClient client) {
+        this.client = client;
+    }
+
+    @Override
+    public BulkResponse bulk(BulkRequest bulkRequest, RequestOptions options) throws IOException {
+        return execute(OS_WRITE_OP_METRIC_PREFIX, () -> client.bulk(bulkRequest, options));
+    }
+
+    @Override
+    public ClearScrollResponse clearScroll(ClearScrollRequest clearScrollRequest, RequestOptions options) throws IOException {
+        return execute(OS_READ_OP_METRIC_PREFIX, () -> client.clearScroll(clearScrollRequest, options));
+    }
+
+    @Override
+    public CreateIndexResponse createIndex(CreateIndexRequest createIndexRequest, RequestOptions options) throws IOException {
+        return execute(OS_WRITE_OP_METRIC_PREFIX, () -> client.indices().create(createIndexRequest, options));
+    }
+
+    @Override
+    public void deleteIndex(DeleteIndexRequest deleteIndexRequest, RequestOptions options) throws IOException {
+        execute(OS_WRITE_OP_METRIC_PREFIX, () -> client.indices().delete(deleteIndexRequest, options));
+    }
+
+    @Override
+    public DeleteResponse delete(DeleteRequest deleteRequest, RequestOptions options) throws IOException {
+        return execute(OS_WRITE_OP_METRIC_PREFIX, () -> client.delete(deleteRequest, options));
+    }
+
+    @Override
+    public GetResponse get(GetRequest getRequest, RequestOptions options) throws IOException {
+        return execute(OS_READ_OP_METRIC_PREFIX, () -> client.get(getRequest, options));
+    }
+
+    @Override
+    public GetIndexResponse getIndex(GetIndexRequest getIndexRequest, RequestOptions options) throws IOException {
+        return execute(OS_READ_OP_METRIC_PREFIX, () -> client.indices().get(getIndexRequest, options));
+    }
+
+    @Override
+    public IndexResponse index(IndexRequest indexRequest, RequestOptions options) throws IOException {
+        return execute(OS_WRITE_OP_METRIC_PREFIX, () -> client.index(indexRequest, options));
+    }
+
+    @Override
+    public Boolean isIndexExists(GetIndexRequest getIndexRequest, RequestOptions options) throws IOException {
+        return execute(OS_READ_OP_METRIC_PREFIX, () -> client.indices().exists(getIndexRequest, options));
+    }
+
+    @Override
+    public SearchResponse search(SearchRequest searchRequest, RequestOptions options) throws IOException {
+        return execute(OS_READ_OP_METRIC_PREFIX, () -> client.search(searchRequest, options));
+    }
+
+    @Override
+    public SearchResponse scroll(SearchScrollRequest searchScrollRequest, RequestOptions options) throws IOException {
+        return execute(OS_READ_OP_METRIC_PREFIX, () -> client.scroll(searchScrollRequest, options));
+    }
+
+    @Override
+    public UpdateResponse update(UpdateRequest updateRequest, RequestOptions options) throws IOException {
+        return execute(OS_WRITE_OP_METRIC_PREFIX, () -> client.update(updateRequest, options));
+    }
+    /**
+     * Executes a given operation, tracks metrics, and handles exceptions.
+     *
+     * @param metricNamePrefix the prefix for the metric name
+     * @param operation        the operation to execute
+     * @param <T>              the return type of the operation
+     * @return the result of the operation
+     * @throws IOException if an I/O exception occurs
+     */
+    private <T> T execute(String metricNamePrefix, IOCallable<T> operation) throws IOException {
+        try {
+            T result = operation.call();
+            MetricsUtil.publishOpenSearchMetric(metricNamePrefix, 200);
+            return result;
+        } catch (Exception e) {
+            OpenSearchException openSearchException = extractOpenSearchException(e);
+            int statusCode = openSearchException != null ? openSearchException.status().getStatus() : 500;
+            MetricsUtil.publishOpenSearchMetric(metricNamePrefix, statusCode);
+            throw e;
+        }
+    }
+
+    /**
+     * Extracts an OpenSearchException from the given Throwable.
+     * Checks if the Throwable is an instance of OpenSearchException or caused by one.
+     *
+     * @param ex the exception to be checked
+     * @return the extracted OpenSearchException, or null if not found
+     */
+    private OpenSearchException extractOpenSearchException(Throwable ex) {
+        if (ex instanceof OpenSearchException) {
+            return (OpenSearchException) ex;
+        } else if (ex.getCause() instanceof OpenSearchException) {
+            return (OpenSearchException) ex.getCause();
+        }
+        return null;
+    }
+
+    /**
+     * Functional interface for operations that can throw IOException.
+     *
+     * @param <T> the return type of the operation
+     */
+    @FunctionalInterface
+    private interface IOCallable<T> {
+        T call() throws IOException;
+    }
+
+    @Override
+    public void close() throws IOException {
+        client.close();
+    }
+}

flint-core/src/main/java/org/opensearch/flint/core/metrics/MetricConstants.java

@@ -0,0 +1,24 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.flint.core.metrics;
+
+/**
+ * This class defines custom metric constants used for monitoring flint operations.
+ */
+public class MetricConstants {
+
+    /**
+     * The prefix for all read-related metrics in OpenSearch.
+     * This constant is used as a part of metric names to categorize and identify metrics related to read operations.
+     */
+    public static final String OS_READ_OP_METRIC_PREFIX = "opensearch.read";
+
+    /**
+     * The prefix for all write-related metrics in OpenSearch.
+     * Similar to OS_READ_METRIC_PREFIX, this constant is used for categorizing and identifying metrics that pertain to write operations.
+     */
+    public static final String OS_WRITE_OP_METRIC_PREFIX = "opensearch.write";
+}

flint-core/src/main/java/org/opensearch/flint/core/metrics/MetricsUtil.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.flint.core.metrics;
+
+import com.codahale.metrics.Counter;
+import org.apache.spark.SparkEnv;
+import org.apache.spark.metrics.source.FlintMetricSource;
+import org.apache.spark.metrics.source.Source;
+import org.opensearch.OpenSearchException;
+import scala.collection.Seq;
+
+import java.util.logging.Logger;
+
+/**
+ * Utility class for managing metrics in the OpenSearch Flint context.
+ */
+public final class MetricsUtil {
+
+    private static final Logger LOG = Logger.getLogger(MetricsUtil.class.getName());
+
+    // Private constructor to prevent instantiation
+    private MetricsUtil() {
+    }
+
+    /**
+     * Publish an OpenSearch metric based on the status code.
+     *
+     * @param metricNamePrefix the prefix for the metric name
+     * @param statusCode       the HTTP status code
+     */
+    public static void publishOpenSearchMetric(String metricNamePrefix, int statusCode) {
+        String metricName = constructMetricName(metricNamePrefix, statusCode);
+        Counter counter = getOrCreateCounter(metricName);
+        if (counter != null) {
+            counter.inc();
+        }
+    }
+
+    // Constructs the metric name based on the provided prefix and status code
+    private static String constructMetricName(String metricNamePrefix, int statusCode) {
+        String metricSuffix = getMetricSuffixForStatusCode(statusCode);
+        return metricNamePrefix + "." + metricSuffix;
+    }
+
+    // Determines the metric suffix based on the HTTP status code
+    private static String getMetricSuffixForStatusCode(int statusCode) {
+        if (statusCode == 403) {
+            return "403.count";
+        } else if (statusCode >= 500) {
+            return "5xx.count";
+        } else if (statusCode >= 400) {
+            return "4xx.count";
+        } else if (statusCode >= 200) {
+            return "2xx.count";
+        }
+        return "unknown.count"; // default for unhandled status codes
+    }
+
+    // Retrieves or creates a new counter for the given metric name
+    private static Counter getOrCreateCounter(String metricName) {
+        SparkEnv sparkEnv = SparkEnv.get();
+        if (sparkEnv == null) {
+            LOG.warning("Spark environment not available, cannot instrument metric: " + metricName);
+            return null;
+        }
+
+        FlintMetricSource flintMetricSource = getOrInitFlintMetricSource(sparkEnv);
+        Counter counter = flintMetricSource.metricRegistry().getCounters().get(metricName);
+        if (counter == null) {
+            counter = flintMetricSource.metricRegistry().counter(metricName);
+        }
+        return counter;
+    }
+
+    // Gets or initializes the FlintMetricSource
+    private static FlintMetricSource getOrInitFlintMetricSource(SparkEnv sparkEnv) {
+        Seq<Source> metricSourceSeq = sparkEnv.metricsSystem().getSourcesByName(FlintMetricSource.FLINT_METRIC_SOURCE_NAME());
+
+        if (metricSourceSeq == null || metricSourceSeq.isEmpty()) {
+            FlintMetricSource metricSource = new FlintMetricSource();
+            sparkEnv.metricsSystem().registerSource(metricSource);
+            return metricSource;
+        }
+        return (FlintMetricSource) metricSourceSeq.head();
+    }
+}