add metrics for HttpGetter connection pool

commafeed-client/src/pages/admin/MetricsPage.tsx

@@ -5,6 +5,7 @@ import { Gauge } from "components/metrics/Gauge"
 import { Meter } from "components/metrics/Meter"
 import { MetricAccordionItem } from "components/metrics/MetricAccordionItem"
 import { Timer } from "components/metrics/Timer"
+import { useEffect } from "react"
 import { useAsync } from "react-async-hook"
 import { TbChartAreaLine, TbClock } from "react-icons/tb"
 
@@ -18,15 +19,27 @@ const shownMeters: Record<string, string> = {
 }
 
 const shownGauges: Record<string, string> = {
-    "com.commafeed.backend.feed.FeedRefreshEngine.queue.size": "Queue size",
+    "com.commafeed.backend.feed.FeedRefreshEngine.queue.size": "Feed Refresh Engine queue size",
-    "com.commafeed.backend.feed.FeedRefreshEngine.worker.active": "Feed Worker active",
+    "com.commafeed.backend.feed.FeedRefreshEngine.worker.active": "Feed Refresh Engine active HTTP workers",
-    "com.commafeed.backend.feed.FeedRefreshEngine.updater.active": "Feed Updater active",
+    "com.commafeed.backend.feed.FeedRefreshEngine.updater.active": "Feed Refresh Engine active database update workers",
+    "com.commafeed.backend.HttpGetter.pool.max": "HttpGetter max connections",
+    "com.commafeed.backend.HttpGetter.pool.available": "HttpGetter available connections",
+    "com.commafeed.backend.HttpGetter.pool.leased": "HttpGetter leased connections",
+    "com.commafeed.backend.HttpGetter.pool.pending": "HttpGetter waiting for available connections",
     "com.commafeed.frontend.ws.WebSocketSessions.users": "WebSocket users",
     "com.commafeed.frontend.ws.WebSocketSessions.sessions": "WebSocket sessions",
 }
 
 export function MetricsPage() {
-    const query = useAsync(async () => await client.admin.getMetrics(), [])
+    const query = useAsync(async () => await client.admin.getMetrics(), [], {
+        // keep previous results available while a new request is pending
+        setLoading: state => ({ ...state, loading: true }),
+    })
+
+    useEffect(() => {
+        const interval = setInterval(() => query.execute(), 2000)
+        return () => clearInterval(interval)
+    }, [query.execute])
 
     if (!query.result) return <Loader />
     const { meters, gauges, timers } = query.result.data
@@ -53,7 +66,7 @@ export function MetricsPage() {
                 <Box pt="xs">
                     {Object.keys(shownGauges).map(g => (
                         <Box key={g}>
-                            <span>{shownGauges[g]}&nbsp;</span>
+                            <span>{shownGauges[g]}:&nbsp;</span>
                             <Gauge gauge={gauges[g]} />
                         </Box>
                     ))}

commafeed-server/src/main/java/com/commafeed/backend/HttpGetter.java

@@ -15,6 +15,7 @@ import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
 import org.apache.hc.client5.http.impl.classic.HttpClientBuilder;
 import org.apache.hc.client5.http.impl.io.PoolingHttpClientConnectionManager;
 import org.apache.hc.client5.http.impl.io.PoolingHttpClientConnectionManagerBuilder;
+import org.apache.hc.client5.http.io.HttpClientConnectionManager;
 import org.apache.hc.client5.http.protocol.HttpClientContext;
 import org.apache.hc.client5.http.protocol.RedirectLocations;
 import org.apache.hc.core5.http.ClassicHttpRequest;
@@ -27,6 +28,7 @@ import org.apache.hc.core5.util.TimeValue;
 import org.apache.hc.core5.util.Timeout;
 import org.eclipse.jetty.http.HttpStatus;
 
+import com.codahale.metrics.MetricRegistry;
 import com.commafeed.CommaFeedConfiguration;
 import com.google.common.collect.Iterables;
 import com.google.common.io.ByteStreams;
@@ -52,11 +54,17 @@ public class HttpGetter {
 	private final DataSize maxResponseSize;
 
 	@Inject
-	public HttpGetter(CommaFeedConfiguration config) {
+	public HttpGetter(CommaFeedConfiguration config, MetricRegistry metrics) {
+		PoolingHttpClientConnectionManager connectionManager = newConnectionManager(config.getApplicationSettings().getBackgroundThreads());
 		String userAgent = Optional.ofNullable(config.getApplicationSettings().getUserAgent())
 				.orElseGet(() -> String.format("CommaFeed/%s (https://github.com/Athou/commafeed)", config.getVersion()));
-		this.client = newClient(userAgent, config.getApplicationSettings().getBackgroundThreads());
+		this.client = newClient(connectionManager, userAgent);
 		this.maxResponseSize = config.getApplicationSettings().getMaxFeedResponseSize();
+
+		metrics.registerGauge(MetricRegistry.name(getClass(), "pool", "max"), () -> connectionManager.getTotalStats().getMax());
+		metrics.registerGauge(MetricRegistry.name(getClass(), "pool", "available"), () -> connectionManager.getTotalStats().getAvailable());
+		metrics.registerGauge(MetricRegistry.name(getClass(), "pool", "leased"), () -> connectionManager.getTotalStats().getLeased());
+		metrics.registerGauge(MetricRegistry.name(getClass(), "pool", "pending"), () -> connectionManager.getTotalStats().getPending());
 	}
 
 	public HttpResult getBinary(String url, int timeout) throws IOException, NotModifiedException {
@@ -151,15 +159,10 @@ public class HttpGetter {
 		}
 	}
 
-	private static CloseableHttpClient newClient(String userAgent, int poolSize) {
+	private static PoolingHttpClientConnectionManager newConnectionManager(int poolSize) {
 		SSLFactory sslFactory = SSLFactory.builder().withUnsafeTrustMaterial().withUnsafeHostnameVerifier().build();
 
-		List<Header> headers = new ArrayList<>();
+		return PoolingHttpClientConnectionManagerBuilder.create()
-		headers.add(new BasicHeader(HttpHeaders.ACCEPT_LANGUAGE, "en"));
-		headers.add(new BasicHeader(HttpHeaders.PRAGMA, "No-cache"));
-		headers.add(new BasicHeader(HttpHeaders.CACHE_CONTROL, "no-cache"));
-
-		PoolingHttpClientConnectionManager connectionManager = PoolingHttpClientConnectionManagerBuilder.create()
 				.setSSLSocketFactory(Apache5SslUtils.toSocketFactory(sslFactory))
 				.setDefaultConnectionConfig(
 						ConnectionConfig.custom().setConnectTimeout(Timeout.ofSeconds(5)).setTimeToLive(TimeValue.ofSeconds(30)).build())
@@ -167,6 +170,14 @@ public class HttpGetter {
 				.setMaxConnTotal(poolSize)
 				.build();
 
+	}
+
+	private static CloseableHttpClient newClient(HttpClientConnectionManager connectionManager, String userAgent) {
+		List<Header> headers = new ArrayList<>();
+		headers.add(new BasicHeader(HttpHeaders.ACCEPT_LANGUAGE, "en"));
+		headers.add(new BasicHeader(HttpHeaders.PRAGMA, "No-cache"));
+		headers.add(new BasicHeader(HttpHeaders.CACHE_CONTROL, "no-cache"));
+
 		return HttpClientBuilder.create()
 				.useSystemProperties()
 				.disableAutomaticRetries()

commafeed-server/src/test/java/com/commafeed/backend/HttpGetterTest.java

@@ -15,6 +15,7 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
+import org.mockito.Mockito;
 import org.mockserver.client.MockServerClient;
 import org.mockserver.junit.jupiter.MockServerExtension;
 import org.mockserver.model.ConnectionOptions;
@@ -23,6 +24,7 @@ import org.mockserver.model.HttpRequest;
 import org.mockserver.model.HttpResponse;
 import org.mockserver.model.MediaType;
 
+import com.codahale.metrics.MetricRegistry;
 import com.commafeed.CommaFeedConfiguration;
 import com.commafeed.CommaFeedConfiguration.ApplicationSettings;
 import com.commafeed.backend.HttpGetter.HttpResponseException;
@@ -57,7 +59,7 @@ class HttpGetterTest {
 		CommaFeedConfiguration config = new CommaFeedConfiguration();
 		config.setApplicationSettings(settings);
 
-		this.getter = new HttpGetter(config);
+		this.getter = new HttpGetter(config, Mockito.mock(MetricRegistry.class));
 	}
 
 	@ParameterizedTest