feat: adds createdTimestamp to counters exposed via prometheus protobuf protocol

Signed-off-by: cmaune <[email protected]>

Author: cmaune

prometheus-metrics-core/src/test/java/io/prometheus/metrics/core/metrics/CounterTest.java

@@ -120,8 +120,8 @@ public void testTotalStrippedFromName(String name) {
     Metrics.MetricFamily protobufData =
         new PrometheusProtobufWriterImpl().convert(counter.collect(), EscapingScheme.ALLOW_UTF8);
     assertThat(ProtobufUtil.shortDebugString(protobufData))
-        .isEqualTo(
-            "name: \"my_counter_seconds_total\" type: COUNTER metric { counter { value: 0.0 } }");
+        .matches(
+            "^name: \"my_counter_seconds_total\" type: COUNTER metric \\{ counter \\{ value: 0.0 created_timestamp \\{ seconds: \\d+ nanos: \\d+ } } }$");
   }
 
   @Test

prometheus-metrics-exposition-formats/src/main/java/io/prometheus/metrics/expositionformats/internal/PrometheusProtobufWriterImpl.java

@@ -130,6 +130,10 @@ private Metrics.Metric.Builder convert(CounterDataPointSnapshot data, EscapingSc
     if (data.getExemplar() != null) {
       counterBuilder.setExemplar(convert(data.getExemplar(), scheme));
     }
+    if (data.hasCreatedTimestamp()) {
+      counterBuilder.setCreatedTimestamp(
+          ProtobufUtil.timestampFromMillis(data.getCreatedTimestampMillis()));
+    }
     Metrics.Metric.Builder metricBuilder = Metrics.Metric.newBuilder();
     addLabels(metricBuilder, data.getLabels(), scheme);
     metricBuilder.setCounter(counterBuilder.build());

prometheus-metrics-exposition-textformats/src/test/java/io/prometheus/metrics/expositionformats/ExpositionFormatsTest.java

@@ -192,6 +192,7 @@ public void testCounterComplete() throws IOException {
             + "value: 0.8 "
             + exemplar1protoString
             + " "
+            + "created_timestamp { seconds: 1672850385 nanos: 800000000 } "
             + "} "
             + "timestamp_ms: 1672850685829 "
             + "} "
@@ -202,6 +203,7 @@ public void testCounterComplete() throws IOException {
             + "value: 0.9 "
             + exemplar2protoString
             + " "
+            + "created_timestamp { seconds: 1672850285 } "
             + "} "
             + "timestamp_ms: 1672850585820 "
             + "}";