001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.http.prometheus;
019
020import static java.nio.charset.StandardCharsets.UTF_8;
021import static org.junit.jupiter.api.Assertions.assertTrue;
022
023import java.io.ByteArrayOutputStream;
024import java.io.IOException;
025import java.io.OutputStreamWriter;
026import org.apache.hadoop.hbase.testclassification.MiscTests;
027import org.apache.hadoop.hbase.testclassification.SmallTests;
028import org.apache.hadoop.metrics2.MetricsSystem;
029import org.apache.hadoop.metrics2.annotation.Metric;
030import org.apache.hadoop.metrics2.annotation.Metrics;
031import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem;
032import org.apache.hadoop.metrics2.lib.MutableCounterLong;
033import org.junit.jupiter.api.Tag;
034import org.junit.jupiter.api.Test;
035
036/**
037 * Test prometheus Sink.
038 */
039@Tag(SmallTests.TAG)
040@Tag(MiscTests.TAG)
041public class TestPrometheusServlet {
042
043  @Test
044  public void testPublish() throws IOException {
045    // GIVEN
046    MetricsSystem metrics = DefaultMetricsSystem.instance();
047    metrics.init("test");
048    TestMetrics testMetrics = metrics.register("TestMetrics", "Testing metrics", new TestMetrics());
049    metrics.start();
050
051    testMetrics.numBucketCreateFails.incr();
052    metrics.publishMetricsNow();
053    ByteArrayOutputStream stream = new ByteArrayOutputStream();
054    OutputStreamWriter writer = new OutputStreamWriter(stream, UTF_8);
055
056    // WHEN
057    PrometheusHadoopServlet prom2Servlet = new PrometheusHadoopServlet();
058    // Test with no description
059    prom2Servlet.writeMetrics(writer, false, null);
060
061    // THEN
062    String writtenMetrics = stream.toString(UTF_8.name());
063    System.out.println(writtenMetrics);
064    assertTrue(writtenMetrics.contains("test_metrics_num_bucket_create_fails{context=\"dfs\""),
065      "The expected metric line is missing from prometheus metrics output");
066
067    metrics.stop();
068    metrics.shutdown();
069  }
070
071  /**
072   * Example metric pojo.
073   */
074  @Metrics(about = "Test Metrics", context = "dfs")
075  private static class TestMetrics {
076
077    @Metric
078    private MutableCounterLong numBucketCreateFails;
079  }
080}