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Keep track of HTTPServer instances (#40)
Signed-off-by: Mickael Maison <[email protected]>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,91 @@ | ||
| /* | ||
| * Copyright Strimzi authors. | ||
| * License: Apache License 2.0 (see the file LICENSE or http://apache.org/licenses/LICENSE-2.0.html). | ||
| */ | ||
| package io.strimzi.kafka.metrics; | ||
|
|
||
| import io.prometheus.metrics.exporter.httpserver.HTTPServer; | ||
| import io.prometheus.metrics.model.registry.PrometheusRegistry; | ||
| import org.slf4j.Logger; | ||
| import org.slf4j.LoggerFactory; | ||
|
|
||
| import java.io.IOException; | ||
| import java.util.HashMap; | ||
| import java.util.Map; | ||
| import java.util.concurrent.atomic.AtomicInteger; | ||
|
|
||
| /** | ||
| * Class to keep track of all the HTTP servers started by all the Kafka components in a JVM. | ||
| */ | ||
| public class HttpServers { | ||
|
|
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| private final static Logger LOG = LoggerFactory.getLogger(HttpServers.class); | ||
| private static final Map<Listener, ServerCounter> SERVERS = new HashMap<>(); | ||
|
|
||
| /** | ||
| * Get or create a new HTTP server if there isn't an existing instance for the specified listener. | ||
| * @param listener The host and port | ||
| * @param registry The Prometheus registry to expose | ||
| * @return A ServerCounter instance | ||
| * @throws IOException if the HTTP server does not exist and cannot be started | ||
| */ | ||
| public synchronized static ServerCounter getOrCreate(Listener listener, PrometheusRegistry registry) throws IOException { | ||
| ServerCounter serverCounter = SERVERS.get(listener); | ||
| if (serverCounter == null) { | ||
| serverCounter = new ServerCounter(listener, registry); | ||
| SERVERS.put(listener, serverCounter); | ||
| } | ||
| serverCounter.count.incrementAndGet(); | ||
| return serverCounter; | ||
| } | ||
|
|
||
| /** | ||
| * Release an HTTP server instance. If no other components hold this instance, it is closed. | ||
| * @param serverCounter The HTTP server instance to release | ||
| */ | ||
| public synchronized static void release(ServerCounter serverCounter) { | ||
| if (serverCounter.close()) { | ||
| SERVERS.remove(serverCounter.listener); | ||
| } | ||
| } | ||
|
|
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| /** | ||
| * Class used to keep track of the HTTP server started on a listener. | ||
| */ | ||
| public static class ServerCounter { | ||
|
|
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| private final AtomicInteger count; | ||
| private final HTTPServer server; | ||
| private final Listener listener; | ||
|
|
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| private ServerCounter(Listener listener, PrometheusRegistry registry) throws IOException { | ||
| this.count = new AtomicInteger(); | ||
| this.server = HTTPServer.builder() | ||
| .hostname(listener.host) | ||
| .port(listener.port) | ||
| .registry(registry) | ||
| .buildAndStart(); | ||
| LOG.debug("Started HTTP server on http://{}:{}", listener.host, server.getPort()); | ||
| this.listener = listener; | ||
| } | ||
|
|
||
| /** | ||
| * The port this HTTP server instance is listening on. If the listener port is 0, this returns the actual port | ||
| * that is used. | ||
| * @return The port number | ||
| */ | ||
| public int port() { | ||
| return server.getPort(); | ||
| } | ||
|
|
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| private synchronized boolean close() { | ||
| int remaining = count.decrementAndGet(); | ||
| if (remaining == 0) { | ||
| server.close(); | ||
| LOG.debug("Stopped HTTP server on http://{}:{}", listener.host, server.getPort()); | ||
| return true; | ||
| } | ||
| return false; | ||
| } | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,74 @@ | ||
| /* | ||
| * Copyright Strimzi authors. | ||
| * License: Apache License 2.0 (see the file LICENSE or http://apache.org/licenses/LICENSE-2.0.html). | ||
| */ | ||
| package io.strimzi.kafka.metrics; | ||
|
|
||
| import org.apache.kafka.common.config.ConfigDef; | ||
| import org.apache.kafka.common.config.ConfigException; | ||
|
|
||
| import java.util.Objects; | ||
| import java.util.regex.Matcher; | ||
| import java.util.regex.Pattern; | ||
|
|
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| import static io.strimzi.kafka.metrics.PrometheusMetricsReporterConfig.LISTENER_CONFIG; | ||
|
|
||
| /** | ||
| * Class parsing and handling the listener specified via {@link PrometheusMetricsReporterConfig#LISTENER_CONFIG} for | ||
| * the HTTP server used to expose the metrics. | ||
| */ | ||
| public class Listener { | ||
|
|
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| private static final Pattern PATTERN = Pattern.compile("http://\\[?([0-9a-zA-Z\\-%._:]*)]?:([0-9]+)"); | ||
|
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| final String host; | ||
| final int port; | ||
|
|
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| /* test */ Listener(String host, int port) { | ||
| this.host = host; | ||
| this.port = port; | ||
| } | ||
|
|
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| static Listener parseListener(String listener) { | ||
| Matcher matcher = PATTERN.matcher(listener); | ||
| if (matcher.matches()) { | ||
| String host = matcher.group(1); | ||
| int port = Integer.parseInt(matcher.group(2)); | ||
| return new Listener(host, port); | ||
| } else { | ||
| throw new ConfigException(LISTENER_CONFIG, listener, "Listener must be of format http://[host]:[port]"); | ||
| } | ||
| } | ||
|
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| @Override | ||
| public String toString() { | ||
| return "http://" + host + ":" + port; | ||
| } | ||
|
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| @Override | ||
| public boolean equals(Object o) { | ||
| if (this == o) return true; | ||
| if (o == null || getClass() != o.getClass()) return false; | ||
| Listener listener = (Listener) o; | ||
| return port == listener.port && Objects.equals(host, listener.host); | ||
| } | ||
|
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| @Override | ||
| public int hashCode() { | ||
| return Objects.hash(host, port); | ||
| } | ||
|
|
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| /** | ||
| * Validator to check the user provided listener configuration | ||
| */ | ||
| static class ListenerValidator implements ConfigDef.Validator { | ||
|
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| @Override | ||
| public void ensureValid(String name, Object value) { | ||
| Matcher matcher = PATTERN.matcher(String.valueOf(value)); | ||
| if (!matcher.matches()) { | ||
| throw new ConfigException(name, value, "Listener must be of format http://[host]:[port]"); | ||
| } | ||
| } | ||
| } | ||
| } |
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62 changes: 62 additions & 0 deletions
62
src/test/java/io/strimzi/kafka/metrics/HttpServersTest.java
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,62 @@ | ||
| /* | ||
| * Copyright Strimzi authors. | ||
| * License: Apache License 2.0 (see the file LICENSE or http://apache.org/licenses/LICENSE-2.0.html). | ||
| */ | ||
| package io.strimzi.kafka.metrics; | ||
|
|
||
| import io.prometheus.metrics.model.registry.PrometheusRegistry; | ||
| import org.junit.jupiter.api.Test; | ||
|
|
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| import java.io.IOException; | ||
| import java.net.HttpURLConnection; | ||
| import java.net.URL; | ||
|
|
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| import static org.junit.jupiter.api.Assertions.assertFalse; | ||
| import static org.junit.jupiter.api.Assertions.assertSame; | ||
| import static org.junit.jupiter.api.Assertions.assertTrue; | ||
|
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| public class HttpServersTest { | ||
|
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| private final PrometheusRegistry registry = new PrometheusRegistry(); | ||
|
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| @Test | ||
| public void testLifecycle() throws IOException { | ||
| Listener listener1 = Listener.parseListener("http://localhost:0"); | ||
| HttpServers.ServerCounter server1 = HttpServers.getOrCreate(listener1, registry); | ||
| assertTrue(listenerStarted(listener1.host, server1.port())); | ||
|
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| Listener listener2 = Listener.parseListener("http://localhost:0"); | ||
| HttpServers.ServerCounter server2 = HttpServers.getOrCreate(listener2, registry); | ||
| assertTrue(listenerStarted(listener2.host, server2.port())); | ||
| assertSame(server1, server2); | ||
|
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| Listener listener3 = Listener.parseListener("http://127.0.0.1:0"); | ||
| HttpServers.ServerCounter server3 = HttpServers.getOrCreate(listener3, registry); | ||
| assertTrue(listenerStarted(listener3.host, server3.port())); | ||
|
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| HttpServers.release(server1); | ||
| assertTrue(listenerStarted(listener1.host, server1.port())); | ||
| assertTrue(listenerStarted(listener2.host, server2.port())); | ||
| assertTrue(listenerStarted(listener3.host, server3.port())); | ||
|
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| HttpServers.release(server2); | ||
| assertFalse(listenerStarted(listener1.host, server1.port())); | ||
| assertFalse(listenerStarted(listener2.host, server2.port())); | ||
| assertTrue(listenerStarted(listener3.host, server3.port())); | ||
|
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| HttpServers.release(server3); | ||
| assertFalse(listenerStarted(listener3.host, server3.port())); | ||
| } | ||
|
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| private boolean listenerStarted(String host, int port) { | ||
| try { | ||
| URL url = new URL("http://" + host + ":" + port + "/metrics"); | ||
| HttpURLConnection con = (HttpURLConnection) url.openConnection(); | ||
| con.setRequestMethod("HEAD"); | ||
| con.connect(); | ||
| return con.getResponseCode() == HttpURLConnection.HTTP_OK; | ||
| } catch (IOException ioe) { | ||
| return false; | ||
| } | ||
| } | ||
| } |
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