Merge 55a1bacceb into 4237a26517

2025-07-29 01:26:14 -07:00 · 2025-07-29 01:26:14 -07:00 · 701cd3f7f5
parent 4237a26517 55a1bacceb
commit 701cd3f7f5
2 changed files with 161 additions and 11 deletions
--- a/exporters/prometheus/src/main/java/io/opentelemetry/exporter/prometheus/Otel2PrometheusConverter.java
+++ b/exporters/prometheus/src/main/java/io/opentelemetry/exporter/prometheus/Otel2PrometheusConverter.java
@ -42,6 +42,7 @@ import io.prometheus.metrics.model.snapshots.HistogramSnapshot;
 import io.prometheus.metrics.model.snapshots.HistogramSnapshot.HistogramDataPointSnapshot;
 import io.prometheus.metrics.model.snapshots.InfoSnapshot;
 import io.prometheus.metrics.model.snapshots.InfoSnapshot.InfoDataPointSnapshot;
+import io.prometheus.metrics.model.snapshots.Label;
 import io.prometheus.metrics.model.snapshots.Labels;
 import io.prometheus.metrics.model.snapshots.MetricMetadata;
 import io.prometheus.metrics.model.snapshots.MetricSnapshot;
@ -81,6 +82,7 @@ final class Otel2PrometheusConverter {
  private static final String OTEL_SCOPE_ATTRIBUTE_PREFIX = "otel_scope_";
  private static final long NANOS_PER_MILLISECOND = TimeUnit.MILLISECONDS.toNanos(1);
  static final int MAX_CACHE_SIZE = 10;
+  static final int EXEMPLAR_MAX_CODE_POINTS = 128;

  private final boolean otelScopeEnabled;
  @Nullable private final Predicate<String> allowedResourceAttributesFilter;
@ -404,11 +406,12 @@ final class Otel2PrometheusConverter {
    return Exemplars.of(result);
  }

+  @Nullable
  private Exemplar convertExemplar(double value, ExemplarData exemplar) {
    SpanContext spanContext = exemplar.getSpanContext();
+    Labels labels = Labels.EMPTY;
    if (spanContext.isValid()) {
-      return new Exemplar(
-          value,
+      labels =
          convertAttributes(
              null, // resource attributes are only copied for point's attributes
              null, // scope attributes are only needed for point's attributes
@ -416,17 +419,31 @@ final class Otel2PrometheusConverter {
              "trace_id",
              spanContext.getTraceId(),
              "span_id",
-              spanContext.getSpanId()),
-          exemplar.getEpochNanos() / NANOS_PER_MILLISECOND);
+              spanContext.getSpanId());
    } else {
-      return new Exemplar(
-          value,
-          convertAttributes(
-              null, // resource attributes are only copied for point's attributes
-              null, // scope attributes are only needed for point's attributes
-              exemplar.getFilteredAttributes()),
-          exemplar.getEpochNanos() / NANOS_PER_MILLISECOND);
+      labels = convertAttributes(null, null, exemplar.getFilteredAttributes());
    }
+    int codePoints = getCodePoints(labels);
+    if (codePoints > EXEMPLAR_MAX_CODE_POINTS) {
+      THROTTLING_LOGGER.log(
+          Level.WARNING,
+          "exemplar labels have "
+              + codePoints
+              + " unicode code points, exceeding the limit of "
+              + EXEMPLAR_MAX_CODE_POINTS);
+      return null;
+    }
+    return new Exemplar(value, labels, exemplar.getEpochNanos() / NANOS_PER_MILLISECOND);
+  }
+
+  private static int getCodePoints(Labels labels) {
+    int codePoints = 0;
+    for (Label label : labels) {
+      codePoints +=
+          label.getName().codePointCount(0, label.getName().length())
+              + label.getValue().codePointCount(0, label.getValue().length());
+    }
+    return codePoints;
  }

  private InfoSnapshot makeTargetInfo(Resource resource) {
--- a/exporters/prometheus/src/test/java/io/opentelemetry/exporter/prometheus/Otel2PrometheusConverterTest.java
+++ b/exporters/prometheus/src/test/java/io/opentelemetry/exporter/prometheus/Otel2PrometheusConverterTest.java
@ -20,6 +20,9 @@ import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import io.opentelemetry.api.common.AttributeType;
 import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.trace.SpanContext;
+import io.opentelemetry.api.trace.TraceFlags;
+import io.opentelemetry.api.trace.TraceState;
 import io.opentelemetry.sdk.common.InstrumentationScopeInfo;
 import io.opentelemetry.sdk.metrics.data.AggregationTemporality;
 import io.opentelemetry.sdk.metrics.data.MetricData;
@ -31,6 +34,7 @@ import io.opentelemetry.sdk.metrics.internal.data.ImmutableExponentialHistogramP
 import io.opentelemetry.sdk.metrics.internal.data.ImmutableGaugeData;
 import io.opentelemetry.sdk.metrics.internal.data.ImmutableHistogramData;
 import io.opentelemetry.sdk.metrics.internal.data.ImmutableHistogramPointData;
+import io.opentelemetry.sdk.metrics.internal.data.ImmutableLongExemplarData;
 import io.opentelemetry.sdk.metrics.internal.data.ImmutableLongPointData;
 import io.opentelemetry.sdk.metrics.internal.data.ImmutableMetricData;
 import io.opentelemetry.sdk.metrics.internal.data.ImmutableSumData;
@ -491,6 +495,42 @@ class Otel2PrometheusConverterTest {
    throw new IllegalArgumentException("Unsupported metric data type: " + metricDataType);
  }

+  static MetricData createLongMetricDataWithExemplar(
+      String metricName,
+      String metricUnit,
+      @Nullable Attributes attributes,
+      @Nullable Resource resource,
+      Attributes exemplarFilteredAttributes) {
+    Attributes attributesToUse = attributes == null ? Attributes.empty() : attributes;
+    Resource resourceToUse = resource == null ? Resource.getDefault() : resource;
+
+    return ImmutableMetricData.createLongSum(
+        resourceToUse,
+        InstrumentationScopeInfo.create("scope"),
+        metricName,
+        "description",
+        metricUnit,
+        ImmutableSumData.create(
+            true,
+            AggregationTemporality.CUMULATIVE,
+            Collections.singletonList(
+                ImmutableLongPointData.create(
+                    0,
+                    100000,
+                    attributesToUse,
+                    1L,
+                    Collections.singletonList(
+                        ImmutableLongExemplarData.create(
+                            exemplarFilteredAttributes,
+                            1L,
+                            SpanContext.create(
+                                "0669315b30dbe08683c19ed9bd24068b",
+                                "049178b29912fdb4",
+                                TraceFlags.getDefault(),
+                                TraceState.getDefault()),
+                            2))))));
+  }
+
  @Test
  void validateCacheIsBounded() {
    AtomicInteger predicateCalledCount = new AtomicInteger();
@ -547,4 +587,97 @@ class Otel2PrometheusConverterTest {
    // it never saw those resources before.
    assertThat(predicateCalledCount.get()).isEqualTo(2);
  }
+
+  @Test
+  void exemplarLabelsWithinLimit() throws IOException {
+
+    Otel2PrometheusConverter converter = new Otel2PrometheusConverter(true, null);
+    Attributes exemplarfilteredAttributes =
+        Attributes.of(
+            stringKey("client_address"),
+            "127.0.0.6",
+            stringKey("network_peer_address"),
+            "127.0.0.6");
+
+    MetricData metricDataWithExemplar =
+        createLongMetricDataWithExemplar(
+            "metric_hertz",
+            "hertz",
+            Attributes.of(stringKey("foo1"), "bar1", stringKey("foo2"), "bar2"),
+            Resource.create(
+                Attributes.of(stringKey("host"), "localhost", stringKey("cluster"), "mycluster")),
+            exemplarfilteredAttributes);
+    String expectedExemplarLabels =
+        "client_address=\"127.0.0.6\""
+            + ",network_peer_address=\"127.0.0.6\",span_id=\"049178b29912fdb4\""
+            + ",trace_id=\"0669315b30dbe08683c19ed9bd24068b\"";
+    ByteArrayOutputStream out = new ByteArrayOutputStream();
+    MetricSnapshots snapshots =
+        converter.convert(Collections.singletonList(metricDataWithExemplar));
+    ExpositionFormats.init().getOpenMetricsTextFormatWriter().write(out, snapshots);
+    String expositionFormat = new String(out.toByteArray(), StandardCharsets.UTF_8);
+
+    // extract the only metric line
+    List<String> metricLines =
+        Arrays.stream(expositionFormat.split("\n"))
+            .filter(line -> line.startsWith("metric_hertz"))
+            .collect(Collectors.toList());
+    assertThat(metricLines).hasSize(1);
+
+    //  metric_hertz_total{foo1="bar1",foo2="bar2",otel_scope_name="scope"} 1.0 #
+    // {client_address="127.0.0.6",network_peer_address="127.0.0.6",span_id="0002",trace_id="0001"}
+    // 2.0
+    String metricLine = metricLines.get(0);
+    String exemplarPart = metricLine.substring(metricLine.indexOf("#") + 2);
+
+    String exemplarLabels =
+        exemplarPart.substring(exemplarPart.indexOf("{") + 1, exemplarPart.indexOf("}"));
+    assertThat(exemplarLabels).isEqualTo(expectedExemplarLabels);
+  }
+
+  @Test
+  void exemplarLabelsAboveLimit() throws IOException {
+
+    Otel2PrometheusConverter converter = new Otel2PrometheusConverter(true, null);
+    Attributes exemplarfilteredAttributes =
+        Attributes.of(
+            stringKey("client_address"),
+            "127.0.0.6",
+            stringKey("network_peer_address"),
+            "127.0.0.6",
+            stringKey("network_peer_port"),
+            "55579",
+            stringKey("server_address"),
+            "10.3.17.168",
+            stringKey("server_port"),
+            "8081",
+            stringKey("url_path"),
+            "/foo/bar");
+    MetricData metricDataWithExemplar =
+        createLongMetricDataWithExemplar(
+            "metric_hertz",
+            "hertz",
+            Attributes.of(stringKey("foo1"), "bar1", stringKey("foo2"), "bar2"),
+            Resource.create(
+                Attributes.of(stringKey("host"), "localhost", stringKey("cluster"), "mycluster")),
+            exemplarfilteredAttributes);
+    ByteArrayOutputStream out = new ByteArrayOutputStream();
+    MetricSnapshots snapshots =
+        converter.convert(Collections.singletonList(metricDataWithExemplar));
+    ExpositionFormats.init().getOpenMetricsTextFormatWriter().write(out, snapshots);
+    String expositionFormat = new String(out.toByteArray(), StandardCharsets.UTF_8);
+
+    // extract the only metric line
+    List<String> metricLines =
+        Arrays.stream(expositionFormat.split("\n"))
+            .filter(line -> line.startsWith("metric_hertz"))
+            .collect(Collectors.toList());
+    assertThat(metricLines).hasSize(1);
+
+    // metric_hertz_total{foo1="bar1",foo2="bar2",otel_scope_name="scope"} 1.0
+    // no exemplar data as runes limit was reached
+    String metricLine = metricLines.get(0);
+    int exemplarDelimitterPos = metricLine.indexOf("#");
+    assertThat(exemplarDelimitterPos).isEqualTo(-1);
+  }
 }