Add handling for gsum/gcount/created in Prometheus exposition format.

Signed-off-by: Brian Brazil <[email protected]>

simpleclient_common/src/main/java/io/prometheus/client/exporter/common/TextFormat.java

@@ -2,7 +2,12 @@
 
 import java.io.IOException;
 import java.io.Writer;
+import java.util.ArrayList;
+import java.util.Collections;
 import java.util.Enumeration;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
 
 import io.prometheus.client.Collector;
 
@@ -53,31 +58,47 @@ public static void writeFormat(String contentType, Writer writer, Enumeration<Co
    * Write out the text version 0.0.4 of the given MetricFamilySamples.
    */
   public static void write004(Writer writer, Enumeration<Collector.MetricFamilySamples> mfs) throws IOException {
+    Map<String, Collector.MetricFamilySamples> omFamilies = new TreeMap<String, Collector.MetricFamilySamples>();
     /* See http://prometheus.io/docs/instrumenting/exposition_formats/
      * for the output format specification. */
     while(mfs.hasMoreElements()) {
       Collector.MetricFamilySamples metricFamilySamples = mfs.nextElement();
       String name = metricFamilySamples.name;
-      if (metricFamilySamples.type == Collector.Type.COUNTER) {
-        name += "_total";
-      }
       writer.write("# HELP ");
       writer.write(name);
+      if (metricFamilySamples.type == Collector.Type.COUNTER) {
+        writer.write("_total");
+      }
       writer.write(' ');
       writeEscapedHelp(writer, metricFamilySamples.help);
       writer.write('\n');
 
       writer.write("# TYPE ");
       writer.write(name);
+      if (metricFamilySamples.type == Collector.Type.COUNTER) {
+        writer.write("_total");
+      }
       writer.write(' ');
       writer.write(typeString(metricFamilySamples.type));
       writer.write('\n');
 
+      String createdName = name + "_created";
+      String gcountName = name + "_gcount";
+      String gsumName = name + "_gsum";
       for (Collector.MetricFamilySamples.Sample sample: metricFamilySamples.samples) {
-        writer.write(sample.name);
-        if (metricFamilySamples.type == Collector.Type.COUNTER && sample.name.equals(metricFamilySamples.name)) {
-          writer.write("_total");
+        /* OpenMetrics specific sample, put in a gauge at the end. */
+        if (sample.name.equals(createdName)
+            || sample.name.equals(gcountName)
+            || sample.name.equals(gsumName)) {
+          Collector.MetricFamilySamples omFamily = omFamilies.get(sample.name);
+          if (omFamily == null) {
+            omFamily = new Collector.MetricFamilySamples(sample.name, Collector.Type.GAUGE, metricFamilySamples.help, new ArrayList<Collector.MetricFamilySamples.Sample>());
+            omFamilies.put(sample.name, omFamily);
+          }
+          omFamily.samples.add(sample);
+          continue;
         }
+        writer.write(sample.name);
         if (sample.labelNames.size() > 0) {
           writer.write('{');
           for (int i = 0; i < sample.labelNames.size(); ++i) {
@@ -97,6 +118,10 @@ public static void write004(Writer writer, Enumeration<Collector.MetricFamilySam
         writer.write('\n');
       }
     }
+    // Write out any OM-specific samples.
+    if (!omFamilies.isEmpty()) {
+      write004(writer, Collections.enumeration(omFamilies.values()));
+    }
   }
 
   private static void writeEscapedHelp(Writer writer, String s) throws IOException {

simpleclient_common/src/test/java/io/prometheus/client/exporter/common/TextFormatTest.java

@@ -5,6 +5,7 @@
 import java.io.IOException;
 import java.io.StringWriter;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 
 import org.junit.Before;
@@ -57,6 +58,17 @@ public void testCounterOutput() throws IOException {
                  + "nolabels_total 1.0\n", writer.toString());
   }
 
+  @Test
+  public void testCounterWithTotalOutput() throws IOException {
+    Counter noLabels = Counter.build().name("nolabels_total").help("help").register(registry);
+    noLabels.inc();
+    TextFormat.write004(writer, registry.metricFamilySamples());
+    assertEquals("# HELP nolabels_total help\n"
+                 + "# TYPE nolabels_total counter\n"
+                 + "nolabels_total 1.0\n", writer.toString());
+  }
+
+
   @Test
   public void testCounterSamplesMissingTotal() throws IOException {
 
@@ -131,6 +143,39 @@ public void testSummaryOutputWithQuantiles() throws IOException {
             + "labelsAndQuantiles_sum{l=\"a\",} 2.0\n", writer.toString());
   }
 
+  @Test
+  public void testGaugeHistogramOutput() throws IOException {
+    class CustomCollector extends Collector {
+      public List<MetricFamilySamples> collect() {
+        List<MetricFamilySamples> mfs = new ArrayList<MetricFamilySamples>();
+        ArrayList<String> labelNames = new ArrayList<String>();
+        ArrayList<String> labelValues = new ArrayList<String>();
+        ArrayList<MetricFamilySamples.Sample> samples = new ArrayList<Collector.MetricFamilySamples.Sample>();
+        samples.add(new MetricFamilySamples.Sample("nolabels_bucket", Arrays.asList("le"), Arrays.asList("+Inf"), 2.0));
+        samples.add(new MetricFamilySamples.Sample("nolabels_gcount", labelNames, labelValues, 2.0));
+        samples.add(new MetricFamilySamples.Sample("nolabels_gsum", labelNames, labelValues, 7.0));
+        samples.add(new MetricFamilySamples.Sample("nolabels_created", labelNames, labelValues, 1234.0));
+        mfs.add(new MetricFamilySamples("nolabels", Collector.Type.GAUGE_HISTOGRAM, "help", samples));
+        return mfs;
+      }
+    }
+    new CustomCollector().register(registry);
+    writer = new StringWriter();
+    TextFormat.write004(writer, registry.metricFamilySamples());
+    assertEquals("# HELP nolabels help\n"
+            + "# TYPE nolabels histogram\n"
+            + "nolabels_bucket{le=\"+Inf\",} 2.0\n"
+            + "# HELP nolabels_created help\n"
+            + "# TYPE nolabels_created gauge\n"
+            + "nolabels_created 1234.0\n"
+            + "# HELP nolabels_gcount help\n"
+            + "# TYPE nolabels_gcount gauge\n"
+            + "nolabels_gcount 2.0\n"
+            + "# HELP nolabels_gsum help\n"
+            + "# TYPE nolabels_gsum gauge\n"
+            + "nolabels_gsum 7.0\n", writer.toString());
+  }
+
   @Test
   public void testLabelsOutput() throws IOException {
     Gauge labels = Gauge.build().name("labels").help("help").labelNames("l").register(registry);