add sample to emit client metrics for prometheus

Author: longquanzheng

build.gradle

@@ -38,6 +38,10 @@ dependencies {
     compile group: 'com.uber.cadence', name: 'cadence-client', version: '2.7.8'
     compile group: 'commons-configuration', name: 'commons-configuration', version: '1.9'
     compile group: 'ch.qos.logback', name: 'logback-classic', version: '1.2.3'
+    compile group: 'com.uber.m3', name: 'tally-core', version: '0.10.0'
+    compile group: 'com.uber.m3', name: 'tally-prometheus', version: '0.10.0'
+    compile group: 'io.prometheus', name: 'simpleclient', version: '0.10.0'
+    compile group: 'io.prometheus', name: 'simpleclient_httpserver', version: '0.10.0'
     testCompile group: 'junit', name: 'junit', version: '4.12'
     testCompile group: 'org.mockito', name: 'mockito-all', version: '1.10.19'
     testCompile group: 'org.powermock', name: 'powermock-api-mockito', version: '1.7.3'

src/main/java/com/uber/cadence/samples/hello/HelloMetric.java

@@ -0,0 +1,192 @@
+/*
+ *  Copyright 2012-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ *  Modifications copyright (C) 2017 Uber Technologies, Inc.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"). You may not
+ *  use this file except in compliance with the License. A copy of the License is
+ *  located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ *  or in the "license" file accompanying this file. This file 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 com.uber.cadence.samples.hello;
+
+import static com.uber.cadence.samples.common.SampleConstants.DOMAIN;
+
+import com.uber.cadence.activity.ActivityMethod;
+import com.uber.cadence.client.WorkflowClient;
+import com.uber.cadence.worker.Worker;
+import com.uber.cadence.worker.WorkerOptions;
+import com.uber.cadence.workflow.Workflow;
+import com.uber.cadence.workflow.WorkflowMethod;
+import com.uber.m3.tally.Buckets;
+import com.uber.m3.tally.Capabilities;
+import com.uber.m3.tally.Counter;
+import com.uber.m3.tally.Gauge;
+import com.uber.m3.tally.Histogram;
+import com.uber.m3.tally.RootScopeBuilder;
+import com.uber.m3.tally.Scope;
+import com.uber.m3.tally.ScopeCloseException;
+import com.uber.m3.tally.Timer;
+import com.uber.m3.tally.prometheus.PrometheusReporter;
+import com.uber.m3.util.Duration;
+import com.uber.m3.util.ImmutableMap;
+import io.prometheus.client.CollectorRegistry;
+import io.prometheus.client.exporter.HTTPServer;
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.util.Map;
+
+/**
+ * Hello World Cadence workflow that executes a single activity. Requires a local instance the
+ * Cadence service to be running.
+ */
+public class HelloMetric {
+
+  static final String TASK_LIST = "HelloActivity";
+
+  /** Workflow interface has to have at least one method annotated with @WorkflowMethod. */
+  public interface GreetingWorkflow {
+    /** @return greeting string */
+    @WorkflowMethod(executionStartToCloseTimeoutSeconds = 10, taskList = TASK_LIST)
+    String getGreeting(String name);
+  }
+
+  /** Activity interface is just a POJI. */
+  public interface GreetingActivities {
+    @ActivityMethod(scheduleToCloseTimeoutSeconds = 2)
+    String composeGreeting(String greeting, String name);
+  }
+
+  /** GreetingWorkflow implementation that calls GreetingsActivities#composeGreeting. */
+  public static class GreetingWorkflowImpl implements GreetingWorkflow {
+
+    /**
+     * Activity stub implements activity interface and proxies calls to it to Cadence activity
+     * invocations. Because activities are reentrant, only a single stub can be used for multiple
+     * activity invocations.
+     */
+    private final GreetingActivities activities =
+        Workflow.newActivityStub(GreetingActivities.class);
+
+    @Override
+    public String getGreeting(String name) {
+      // This is a blocking call that returns only after the activity has completed.
+      return activities.composeGreeting("Hello", name);
+    }
+  }
+
+  static class GreetingActivitiesImpl implements GreetingActivities {
+    @Override
+    public String composeGreeting(String greeting, String name) {
+      return greeting + " " + name + "!";
+    }
+  }
+
+  public static void main(String[] args) throws IOException {
+    // Start a worker that hosts both workflow and activity implementations.
+    Worker.Factory factory = new Worker.Factory(DOMAIN);
+    PrometheusReporter.builder().registry(CollectorRegistry.defaultRegistry).build();
+    final WorkerOptions workerOptions =
+        new WorkerOptions.Builder().setMetricsScope(createMetricScope()).build();
+    Worker worker = factory.newWorker(TASK_LIST, workerOptions);
+    // Workflows are stateful. So you need a type to create instances.
+    worker.registerWorkflowImplementationTypes(GreetingWorkflowImpl.class);
+    // Activities are stateless and thread safe. So a shared instance is used.
+    worker.registerActivitiesImplementations(new GreetingActivitiesImpl());
+    // Start listening to the workflow and activity task lists.
+    factory.start();
+
+    // Start a workflow execution. Usually this is done from another program.
+    WorkflowClient workflowClient = WorkflowClient.newInstance(DOMAIN);
+    // Get a workflow stub using the same task list the worker uses.
+    GreetingWorkflow workflow = workflowClient.newWorkflowStub(GreetingWorkflow.class);
+    // Execute a workflow waiting for it to complete.
+    String greeting = workflow.getGreeting("World");
+    System.out.println(greeting);
+  }
+
+  private static Scope createMetricScope() throws IOException {
+    CollectorRegistry registry = CollectorRegistry.defaultRegistry;
+    HTTPServer httpServer = new HTTPServer(new InetSocketAddress(9098), registry);
+    PrometheusReporter reporter = PrometheusReporter.builder().registry(registry).build();
+    Scope scope = new RootScopeBuilder().reporter(reporter).reportEvery(Duration.ofSeconds(1));
+    return new PrometheusScope(scope);
+  }
+}
+
+
+/**
+ * PrometheusScope will replace all "-"(dash) into "_"(underscore) so that it meets the requirement
+ * in https://prometheus.io/docs/concepts/data_model/
+ */
+class PrometheusScope implements Scope {
+
+  private Scope scope;
+
+  PrometheusScope(Scope scope) {
+    this.scope = scope;
+  }
+
+  private String fixName(String name) {
+    String newName = name.replace('-', '_');
+    return newName;
+  }
+
+  private Map<String, String> fixTags(Map<String, String> tags) {
+    ImmutableMap.Builder<String, String> builder = new ImmutableMap.Builder<>();
+    tags.forEach((key, value) -> builder.put(fixName(key), fixName(value)));
+    return builder.build();
+  }
+
+  @Override
+  public Counter counter(final String name) {
+    String newName = fixName(name);
+    return scope.counter(newName);
+  }
+
+  @Override
+  public Gauge gauge(final String name) {
+    String newName = fixName(name);
+    return scope.gauge(newName);
+  }
+
+  @Override
+  public Timer timer(final String name) {
+    String newName = fixName(name);
+    return scope.timer(newName);
+  }
+
+  @Override
+  public Histogram histogram(final String name, final Buckets buckets) {
+    String newName = fixName(name);
+    return scope.histogram(newName, buckets);
+  }
+
+  @Override
+  public Scope tagged(final Map<String, String> tags) {
+    return new PrometheusScope(scope.tagged(fixTags(tags)));
+  }
+
+  @Override
+  public Scope subScope(final String name) {
+    String newName = fixName(name);
+    return new PrometheusScope(scope.subScope(newName));
+  }
+
+  @Override
+  public Capabilities capabilities() {
+    return scope.capabilities();
+  }
+
+  @Override
+  public void close() throws ScopeCloseException {
+    scope.close();
+  }
+}