Merge pull request #1167 from brendandburns/prom

Add utilities for instrumentation.

Author: k8s-ci-robot

examples/pom.xml

@@ -12,6 +12,16 @@
 		<relativePath>../pom.xml</relativePath>
 	</parent>
 	<dependencies>
+        <dependency>
+            <groupId>io.prometheus</groupId>
+            <artifactId>simpleclient</artifactId>
+            <version>0.9.0</version>
+        </dependency>
+        <dependency>
+            <groupId>io.prometheus</groupId>
+            <artifactId>simpleclient_httpserver</artifactId>
+            <version>0.9.0</version>
+        </dependency>
 		<dependency>
 			<groupId>io.kubernetes</groupId>
 			<artifactId>client-java-api</artifactId>

examples/src/main/java/io/kubernetes/client/examples/PrometheusExample.java

@@ -0,0 +1,66 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+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.kubernetes.client.examples;
+
+import io.kubernetes.client.monitoring.Monitoring;
+import io.kubernetes.client.openapi.ApiClient;
+import io.kubernetes.client.openapi.ApiException;
+import io.kubernetes.client.openapi.Configuration;
+import io.kubernetes.client.openapi.apis.CoreV1Api;
+import io.kubernetes.client.openapi.models.V1Pod;
+import io.kubernetes.client.openapi.models.V1PodList;
+import io.kubernetes.client.util.Config;
+import java.io.IOException;
+
+/**
+ * A simple example of how to use the Java API with Prometheus metrics
+ *
+ * <p>Easiest way to run this: mvn exec:java
+ * -Dexec.mainClass="io.kubernetes.client.examples.PrometheusExample"
+ *
+ * <p>From inside $REPO_DIR/examples
+ */
+public class PrometheusExample {
+  public static void main(String[] args) throws IOException, ApiException {
+    ApiClient client = Config.defaultClient();
+    Configuration.setDefaultApiClient(client);
+
+    // Install an HTTP Interceptor that adds metrics
+    Monitoring.installMetrics(client);
+
+    // Install a simple HTTP server to serve prometheus metrics. If you already are serving
+    // metrics elsewhere, this is unnecessary.
+    Monitoring.startMetricsServer("localhost", 8080);
+
+    CoreV1Api api = new CoreV1Api();
+
+    while (true) {
+      // A request that should return 200
+      V1PodList list =
+          api.listPodForAllNamespaces(null, null, null, null, null, null, null, null, null);
+      // A request that should return 404
+      try {
+        V1Pod pod = api.readNamespacedPod("foo", "bar", null, null, null);
+      } catch (ApiException ex) {
+        if (ex.getCode() != 404) {
+          throw ex;
+        }
+      }
+      try {
+        Thread.sleep(10000);
+      } catch (InterruptedException ex) {
+        ex.printStackTrace();
+      }
+    }
+  }
+}

util/pom.xml

@@ -12,6 +12,18 @@
         <relativePath>../pom.xml</relativePath>
     </parent>
     <dependencies>
+        <dependency>
+            <groupId>io.prometheus</groupId>
+            <artifactId>simpleclient</artifactId>
+            <version>0.9.0</version>
+            <optional>true</optional>
+        </dependency>
+        <dependency>
+            <groupId>io.prometheus</groupId>
+            <artifactId>simpleclient_httpserver</artifactId>
+            <version>0.9.0</version>
+            <optional>true</optional>
+        </dependency>
         <dependency>
             <groupId>io.kubernetes</groupId>
             <artifactId>client-java-api</artifactId>

util/src/main/java/io/kubernetes/client/monitoring/Monitoring.java

@@ -0,0 +1,32 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+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.kubernetes.client.monitoring;
+
+import io.kubernetes.client.openapi.ApiClient;
+import io.prometheus.client.exporter.HTTPServer;
+import java.io.IOException;
+
+public class Monitoring {
+  public static void startMetricsServer(int port) throws IOException {
+    new HTTPServer(port);
+  }
+
+  public static void startMetricsServer(String host, int port) throws IOException {
+    new HTTPServer(host, port);
+  }
+
+  public static void installMetrics(ApiClient client) throws IOException {
+    client.setHttpClient(
+        client.getHttpClient().newBuilder().addInterceptor(new PrometheusInterceptor()).build());
+  }
+}

util/src/main/java/io/kubernetes/client/monitoring/PrometheusInterceptor.java

@@ -0,0 +1,50 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+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.kubernetes.client.monitoring;
+
+import io.prometheus.client.Counter;
+import io.prometheus.client.Histogram;
+import java.io.IOException;
+import okhttp3.Interceptor;
+import okhttp3.Response;
+
+public class PrometheusInterceptor implements Interceptor {
+  static final String PREFIX = "k8s_java";
+  static final Counter requests =
+      Counter.build().name(PREFIX + "_requests_total").help("Total requests").register();
+  static final Counter codes =
+      Counter.build()
+          .name(PREFIX + "_response_code_total")
+          .help("Response code total")
+          .labelNames("code")
+          .register();
+  static final Histogram latency =
+      Histogram.build()
+          .name(PREFIX + "_request_latency_seconds")
+          .help("Request latency (seconds)")
+          .register();
+
+  @Override
+  public Response intercept(Interceptor.Chain chain) throws IOException {
+    requests.inc();
+    Histogram.Timer timer = latency.startTimer();
+
+    try {
+      Response response = chain.proceed(chain.request());
+      codes.labels(Integer.toString(response.code())).inc();
+      return response;
+    } finally {
+      timer.observeDuration();
+    }
+  }
+}