Add JMX metrics for S3 http client usage in native FS.

When s3 client was changed to use AWS SDK v2 from AWS SDK v1, the set of s3 pool metrics were missed.

With this PR, these http pool metrics are now exposed via JMX beans. The reference for the http metrics exposed by AWS SDK can be found here:
https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/http/HttpMetric.html

lib/trino-filesystem-s3/src/main/java/io/trino/filesystem/s3/AwsSdkV2HttpClientStats.java

@@ -0,0 +1,80 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.trino.filesystem.s3;
+
+import com.google.errorprone.annotations.ThreadSafe;
+import io.airlift.stats.TimeStat;
+import org.weakref.jmx.Managed;
+import org.weakref.jmx.Nested;
+import software.amazon.awssdk.metrics.SdkMetric;
+
+import java.time.Duration;
+import java.util.concurrent.atomic.AtomicLong;
+
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+import static software.amazon.awssdk.http.HttpMetric.AVAILABLE_CONCURRENCY;
+import static software.amazon.awssdk.http.HttpMetric.LEASED_CONCURRENCY;
+import static software.amazon.awssdk.http.HttpMetric.PENDING_CONCURRENCY_ACQUIRES;
+
+@ThreadSafe
+public class AwsSdkV2HttpClientStats
+{
+    private final TimeStat connectionAcquireLatency = new TimeStat(MILLISECONDS);
+    private final AtomicLong availableConcurrency = new AtomicLong();
+    private final AtomicLong leasedConcurrency = new AtomicLong();
+    private final AtomicLong pendingConcurrencyAcquires = new AtomicLong();
+
+    @Managed
+    @Nested
+    public TimeStat getConnectionAcquireLatency()
+    {
+        return connectionAcquireLatency;
+    }
+
+    @Managed
+    public long getAvailableConcurrency()
+    {
+        return availableConcurrency.get();
+    }
+
+    @Managed
+    public long getLeasedConcurrency()
+    {
+        return leasedConcurrency.get();
+    }
+
+    @Managed
+    public long getPendingConcurrencyAcquires()
+    {
+        return pendingConcurrencyAcquires.get();
+    }
+
+    public void updateConcurrencyStats(SdkMetric<?> metric, int value)
+    {
+        if (metric.equals(AVAILABLE_CONCURRENCY)) {
+            availableConcurrency.set(value);
+        }
+        else if (metric.equals(PENDING_CONCURRENCY_ACQUIRES)) {
+            pendingConcurrencyAcquires.set(value);
+        }
+        else if (metric.equals(LEASED_CONCURRENCY)) {
+            leasedConcurrency.set(value);
+        }
+    }
+
+    public void updateConcurrencyAcquireDuration(Duration duration)
+    {
+        connectionAcquireLatency.addNanos(duration.toNanos());
+    }
+}

lib/trino-filesystem-s3/src/main/java/io/trino/filesystem/s3/S3FileSystemStats.java

@@ -34,6 +34,10 @@
 import static software.amazon.awssdk.core.metrics.CoreMetric.OPERATION_NAME;
 import static software.amazon.awssdk.core.metrics.CoreMetric.RETRY_COUNT;
 import static software.amazon.awssdk.core.metrics.CoreMetric.SERVICE_ID;
+import static software.amazon.awssdk.http.HttpMetric.AVAILABLE_CONCURRENCY;
+import static software.amazon.awssdk.http.HttpMetric.CONCURRENCY_ACQUIRE_DURATION;
+import static software.amazon.awssdk.http.HttpMetric.LEASED_CONCURRENCY;
+import static software.amazon.awssdk.http.HttpMetric.PENDING_CONCURRENCY_ACQUIRES;
 
 public class S3FileSystemStats
 {
@@ -49,6 +53,7 @@ public class S3FileSystemStats
     private final AwsSdkV2ApiCallStats completeMultipartUpload = new AwsSdkV2ApiCallStats();
     private final AwsSdkV2ApiCallStats abortMultipartUpload = new AwsSdkV2ApiCallStats();
     private final AwsSdkV2ApiCallStats uploadPart = new AwsSdkV2ApiCallStats();
+    private final AwsSdkV2HttpClientStats httpClientStats = new AwsSdkV2HttpClientStats();
 
     private static final AwsSdkV2ApiCallStats dummy = new DummyAwsSdkV2ApiCallStats();
 
@@ -129,6 +134,13 @@ public AwsSdkV2ApiCallStats uploadPart()
         return uploadPart;
     }
 
+    @Managed
+    @Nested
+    public AwsSdkV2HttpClientStats getHttpClientStats()
+    {
+        return httpClientStats;
+    }
+
     public MetricPublisher newMetricPublisher()
     {
         return new JmxMetricPublisher(this);
@@ -137,7 +149,10 @@ public MetricPublisher newMetricPublisher()
     public static final class JmxMetricPublisher
             implements MetricPublisher
     {
-        private static final Set<SdkMetric<?>> ALLOWED_METRICS = Set.of(API_CALL_SUCCESSFUL, RETRY_COUNT, API_CALL_DURATION, ERROR_TYPE);
+        private static final Set<SdkMetric<?>> ALLOWED_METRICS = Set.of(
+                API_CALL_SUCCESSFUL, RETRY_COUNT, API_CALL_DURATION, ERROR_TYPE,
+                AVAILABLE_CONCURRENCY, LEASED_CONCURRENCY, PENDING_CONCURRENCY_ACQUIRES,
+                CONCURRENCY_ACQUIRE_DURATION);
 
         private static final Logger log = Logger.get(JmxMetricPublisher.class);
 
@@ -164,14 +179,14 @@ public void publish(MetricCollection metricCollection)
                 }
 
                 AwsSdkV2ApiCallStats apiCallStats = getApiCallStats(operationName.get());
-                publishMetrics(metricCollection, apiCallStats);
+                publishMetrics(metricCollection, apiCallStats, stats.httpClientStats);
             }
             catch (Exception e) {
                 log.warn(e, "Publishing AWS metrics failed");
             }
         }
 
-        private void publishMetrics(MetricCollection metricCollection, AwsSdkV2ApiCallStats apiCallStats)
+        private void publishMetrics(MetricCollection metricCollection, AwsSdkV2ApiCallStats apiCallStats, AwsSdkV2HttpClientStats httpClientStats)
         {
             metricCollection.stream()
                     .filter(metricRecord -> metricRecord.value() != null && ALLOWED_METRICS.contains(metricRecord.metric()))
@@ -211,9 +226,17 @@ else if (value.equals(SERVER_ERROR.toString())) {
                                 apiCallStats.updateServerErrors();
                             }
                         }
+                        else if (metricRecord.metric().equals(LEASED_CONCURRENCY) || metricRecord.metric().equals(AVAILABLE_CONCURRENCY) || metricRecord.metric().equals(PENDING_CONCURRENCY_ACQUIRES)) {
+                            int value = (int) metricRecord.value();
+                            httpClientStats.updateConcurrencyStats(metricRecord.metric(), value);
+                        }
+                        else if (metricRecord.metric().equals(CONCURRENCY_ACQUIRE_DURATION)) {
+                            Duration duration = (Duration) metricRecord.value();
+                            httpClientStats.updateConcurrencyAcquireDuration(duration);
+                        }
                     });
 
-            metricCollection.children().forEach(child -> publishMetrics(child, apiCallStats));
+            metricCollection.children().forEach(child -> publishMetrics(child, apiCallStats, httpClientStats));
         }
 
         @Override