HADOOP-17893. Improve PrometheusSink for Namenode TopMetrics (#3426)

Signed-off-by: Akira Ajisaka <aajisaka@apache.org>

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/sink/PrometheusMetricsSink.java

@@ -17,6 +17,9 @@
  */
 package org.apache.hadoop.metrics2.sink;
 
+import java.util.ArrayList;
+import java.util.List;
+import java.util.regex.Matcher;
 import org.apache.commons.configuration2.SubsetConfiguration;
 import org.apache.hadoop.metrics2.AbstractMetric;
 import org.apache.hadoop.metrics2.MetricType;
@@ -52,6 +55,13 @@ public class PrometheusMetricsSink implements MetricsSink {
       Pattern.compile("(?<!(^|[A-Z_]))(?=[A-Z])|(?<!^)(?=[A-Z][a-z])");
   private static final Pattern DELIMITERS = Pattern.compile("[^a-zA-Z0-9]+");
 
+  private static final Pattern NN_TOPMETRICS_PATTERN =
+      Pattern.compile(
+          "^(nn_top_user_op_counts_window_ms_\\d+)_op_.*?(total_count|count)$");
+  private static final Pattern NN_TOPMETRICS_TAGS_PATTERN =
+      Pattern
+          .compile("^op=(?<op>\\w+)(.user=(?<user>.*)|)\\.(TotalCount|count)$");
+
   public PrometheusMetricsSink() {
   }
 
@@ -95,25 +105,28 @@ public class PrometheusMetricsSink implements MetricsSink {
   }
 
   public void writeMetrics(Writer writer) throws IOException {
+    List<String> extendMetricsTags = new ArrayList<>();
     for (Map.Entry<String, Map<Collection<MetricsTag>, AbstractMetric>> promMetric :
         promMetrics.entrySet()) {
       AbstractMetric firstMetric = promMetric.getValue().values().iterator().next();
+      String metricKey = getMetricKey(promMetric.getKey(), firstMetric,
+          extendMetricsTags);
 
       StringBuilder builder = new StringBuilder();
       builder.append("# HELP ")
-          .append(promMetric.getKey())
+          .append(metricKey)
           .append(" ")
           .append(firstMetric.description())
           .append("\n")
           .append("# TYPE ")
-          .append(promMetric.getKey())
+          .append(metricKey)
           .append(" ")
           .append(firstMetric.type().toString().toLowerCase())
           .append("\n");
 
       for (Map.Entry<Collection<MetricsTag>, AbstractMetric> metric :
           promMetric.getValue().entrySet()) {
-        builder.append(promMetric.getKey())
+        builder.append(metricKey)
             .append("{");
 
         String sep = "";
@@ -129,6 +142,13 @@ public class PrometheusMetricsSink implements MetricsSink {
             sep = ",";
           }
         }
+        if (!extendMetricsTags.isEmpty()) {
+          //add extend tags
+          for (String tagStr : extendMetricsTags) {
+            builder.append(sep).append(tagStr);
+          }
+          extendMetricsTags.clear();
+        }
         builder.append("} ");
         builder.append(metric.getValue().value());
         builder.append("\n");
@@ -137,4 +157,39 @@ public class PrometheusMetricsSink implements MetricsSink {
       writer.write(builder.toString());
     }
   }
+
+  private String getMetricKey(String promMetricKey, AbstractMetric metric,
+      List<String> extendTags) {
+    Matcher matcher = NN_TOPMETRICS_PATTERN.matcher(promMetricKey);
+    if (matcher.find() && matcher.groupCount() == 2) {
+      extendTags.addAll(parseTopMetricsTags(metric.name()));
+      return String.format("%s_%s",
+          matcher.group(1), matcher.group(2));
+    }
+    return promMetricKey;
+  }
+
+  /**
+   * Parse Custom tags for TopMetrics.
+   *
+   * @param metricName metricName
+   * @return Tags for TopMetrics
+   */
+  private List<String> parseTopMetricsTags(String metricName) {
+    List<String> topMetricsTags = new ArrayList<>();
+    Matcher matcher = NN_TOPMETRICS_TAGS_PATTERN.matcher(metricName);
+    if (matcher.find()) {
+      String op = matcher.group("op");
+      String user = matcher.group("user");
+      // add tag op = "$op"
+      topMetricsTags.add(String
+          .format("op=\"%s\"", op));
+      if (StringUtils.isNoneEmpty(user)) {
+        // add tag user = "$user"
+        topMetricsTags.add(String
+            .format("user=\"%s\"", user));
+      }
+    }
+    return topMetricsTags;
+  }
 }

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/metrics2/sink/TestPrometheusMetricsSink.java

@@ -21,17 +21,25 @@ import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.OutputStreamWriter;
 
+import java.util.ArrayList;
+import java.util.List;
+import org.apache.commons.lang3.StringUtils;
+import org.apache.hadoop.metrics2.MetricsCollector;
+import org.apache.hadoop.metrics2.MetricsRecordBuilder;
+import org.apache.hadoop.metrics2.MetricsSource;
 import org.apache.hadoop.metrics2.MetricsSystem;
 import org.apache.hadoop.metrics2.annotation.Metric;
 import org.apache.hadoop.metrics2.annotation.Metrics;
 import org.apache.hadoop.metrics2.annotation.Metric.Type;
 import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem;
+import org.apache.hadoop.metrics2.lib.Interns;
 import org.apache.hadoop.metrics2.lib.MutableCounterLong;
 
 import org.junit.Assert;
 import org.junit.Test;
 
 import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.assertj.core.api.Assertions.assertThat;
 
 /**
  * Test prometheus Sink.
@@ -219,6 +227,53 @@ public class TestPrometheusMetricsSink {
         sink.prometheusName(recordName, metricName));
   }
 
+  /**
+   * testTopMetricsPublish.
+   */
+  @Test
+  public void testTopMetricsPublish() throws IOException {
+    MetricsSystem metrics = DefaultMetricsSystem.instance();
+
+    metrics.init("test");
+
+    //GIVEN
+    PrometheusMetricsSink sink = new PrometheusMetricsSink();
+
+    metrics.register("prometheus", "prometheus", sink);
+    TestTopMetrics topMetrics = new TestTopMetrics();
+    topMetrics.add("60000");
+    topMetrics.add("1500000");
+    metrics.register(TestTopMetrics.TOPMETRICS_METRICS_SOURCE_NAME,
+        "Top N operations by user", topMetrics);
+
+    metrics.start();
+
+    metrics.publishMetricsNow();
+    ByteArrayOutputStream stream = new ByteArrayOutputStream();
+    OutputStreamWriter writer = new OutputStreamWriter(stream, UTF_8);
+
+    //WHEN
+    sink.writeMetrics(writer);
+    writer.flush();
+
+    //THEN
+    String writtenMetrics = stream.toString(UTF_8.name());
+    System.out.println(writtenMetrics);
+
+    assertThat(writtenMetrics)
+        .contains(
+            "nn_top_user_op_counts_window_ms_60000_total_count{context=\"dfs\"")
+        .contains(
+            "nn_top_user_op_counts_window_ms_60000_count{")
+        .contains(
+            "nn_top_user_op_counts_window_ms_1500000_count{")
+        .contains(
+            "op=\"rename\",user=\"hadoop/TEST_HOSTNAME.com@HOSTNAME.COM\"");
+
+    metrics.stop();
+    metrics.shutdown();
+  }
+
   /**
    * Example metric pojo.
    */
@@ -242,4 +297,38 @@ public class TestPrometheusMetricsSink {
     @Metric
     private MutableCounterLong numBucketCreateFails;
   }
+
+  /**
+   * Example metric TopMetrics.
+   */
+  private class TestTopMetrics implements MetricsSource {
+
+    public static final String TOPMETRICS_METRICS_SOURCE_NAME =
+        "NNTopUserOpCounts";
+    private final List<String> windowMsNames = new ArrayList<>();
+
+    public void add(String windowMs) {
+      windowMsNames.add(String.format(".windowMs=%s", windowMs));
+    }
+
+    @Override
+    public void getMetrics(MetricsCollector collector, boolean all) {
+      for (String windowMs : windowMsNames) {
+        MetricsRecordBuilder rb = collector
+            .addRecord(TOPMETRICS_METRICS_SOURCE_NAME + windowMs)
+            .setContext("dfs");
+        rb.addCounter(
+            Interns.info("op=" + StringUtils.deleteWhitespace("rename")
+                + ".TotalCount", "Total operation count"), 2);
+        rb.addCounter(
+            Interns.info("op=" + StringUtils.deleteWhitespace("rename")
+                + ".user=" + "hadoop/TEST_HOSTNAME.com@HOSTNAME.COM"
+                + ".count", "Total operations performed by user"), 3);
+        rb.addCounter(
+            Interns.info("op=" + StringUtils.deleteWhitespace("delete")
+                + ".user=" + "test_user2"
+                + ".count", "Total operations performed by user"), 4);
+      }
+    }
+  }
 }