Add Jetty's ThreadPool metrics

micrometer-core/src/main/java/io/micrometer/core/instrument/binder/jetty/InstrumentedQueuedThreadPool.java

@@ -0,0 +1,38 @@
+/**
+ * Copyright 2017 Pivotal Software, Inc.
+ * <p>
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.micrometer.core.instrument.binder.jetty;
+
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.Tag;
+import org.eclipse.jetty.util.thread.QueuedThreadPool;
+
+public class InstrumentedQueuedThreadPool extends QueuedThreadPool {
+
+    private final MeterRegistry registry;
+    private final Iterable<Tag> tags;
+
+    public InstrumentedQueuedThreadPool(MeterRegistry registry, Iterable<Tag> tags) {
+        this.registry = registry;
+        this.tags = tags;
+    }
+
+    @Override
+    protected void doStart() throws Exception {
+        super.doStart();
+        JettyServerThreadPoolMetrics threadPoolMetrics = new JettyServerThreadPoolMetrics(this, tags);
+        threadPoolMetrics.bindTo(registry);
+    }
+}

micrometer-core/src/main/java/io/micrometer/core/instrument/binder/jetty/JettyServerThreadPoolMetrics.java

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+/**
+ * Copyright 2017 Pivotal Software, Inc.
+ * <p>
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.micrometer.core.instrument.binder.jetty;
+
+import io.micrometer.core.instrument.Gauge;
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.Tag;
+import io.micrometer.core.instrument.binder.MeterBinder;
+
+public class JettyServerThreadPoolMetrics implements MeterBinder {
+
+    private final InstrumentedQueuedThreadPool threadPool;
+    private final Iterable<Tag> tags;
+
+    public JettyServerThreadPoolMetrics(InstrumentedQueuedThreadPool threadPool, Iterable<Tag> tags) {
+        this.threadPool = threadPool;
+        this.tags = tags;
+    }
+
+    @Override
+    public void bindTo(MeterRegistry registry) {
+        Gauge.builder("jetty.threads.min", threadPool, InstrumentedQueuedThreadPool::getMinThreads)
+             .tags(tags)
+             .description("The number of min threads")
+             .register(registry);
+        Gauge.builder("jetty.threads.max", threadPool, InstrumentedQueuedThreadPool::getMaxThreads)
+             .tags(tags)
+             .description("The number of max threads")
+             .register(registry);
+        Gauge.builder("jetty.threads.current", threadPool, InstrumentedQueuedThreadPool::getThreads)
+             .tags(tags)
+             .description("The current number of current threads")
+             .register(registry);
+        Gauge.builder("jetty.threads.idle", threadPool, InstrumentedQueuedThreadPool::getIdleThreads)
+             .tags(tags)
+             .description("The current number of idle threads")
+             .register(registry);
+        Gauge.builder("jetty.threads.busy", threadPool, InstrumentedQueuedThreadPool::getBusyThreads)
+             .tags(tags)
+             .description("The current number of busy threads")
+             .register(registry);
+    }
+}

micrometer-core/src/test/java/io/micrometer/core/instrument/binder/jetty/JettyServerThreadPoolMetricsTest.java

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+/**
+ * Copyright 2017 Pivotal Software, Inc.
+ * <p>
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.micrometer.core.instrument.binder.jetty;
+
+import io.micrometer.core.instrument.MockClock;
+import io.micrometer.core.instrument.Tag;
+import io.micrometer.core.instrument.simple.SimpleConfig;
+import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
+import org.eclipse.jetty.server.Connector;
+import org.eclipse.jetty.server.Server;
+import org.eclipse.jetty.server.ServerConnector;
+import org.eclipse.jetty.util.thread.QueuedThreadPool;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.Collections;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class JettyServerThreadPoolMetricsTest {
+    private SimpleMeterRegistry registry;
+    private Server server;
+
+    @BeforeEach
+    void setup() throws Exception {
+        registry = new SimpleMeterRegistry(SimpleConfig.DEFAULT, new MockClock());
+
+        Iterable<Tag> tags = Collections.singletonList(Tag.of("id", "0"));
+        QueuedThreadPool threadPool = new InstrumentedQueuedThreadPool(registry, tags);
+        threadPool.setMinThreads(32);
+        threadPool.setMaxThreads(100);
+        server = new Server(threadPool);
+        ServerConnector connector = new ServerConnector(server);
+        server.setConnectors(new Connector[] { connector });
+        server.start();
+    }
+
+    @AfterEach
+    void teardown() throws Exception {
+        server.stop();
+    }
+
+    @Test
+    void threadsMetrics() throws Exception {
+        assertThat(registry.get("jetty.threads.min").gauge().value()).isEqualTo(32.0);
+        assertThat(registry.get("jetty.threads.max").gauge().value()).isEqualTo(100.0);
+        assertThat(registry.get("jetty.threads.current").gauge().value()).isNotEqualTo(0.0);
+        assertThat(registry.get("jetty.threads.idle").gauge().value()).isNotEqualTo(0.0);
+        assertThat(registry.get("jetty.threads.busy").gauge().value()).isNotEqualTo(0.0);
+    }
+}