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feat: support metric name filtering in OpenTelemetry exporter (#2344)
Closes the last pending high-priority item in #1816 (as all others have already been addressed). Currently, `PrometheusMetricProducer` always exported all metrics in the registry unconditionally. The code already had a TODO sketching how filtering could be added: https://github.com/prometheus/client_java/blob/9432fdc1933611d34d944d4640ebca3bf91f8ee4/prometheus-metrics-exporter-opentelemetry/src/main/java/io/prometheus/metrics/exporter/opentelemetry/PrometheusMetricProducer.java#L47-L54 this PR implements that by reusing `ExporterFilterProperties` and `MetricNameFilter`, as already done by `PrometheusScrapeHandler`. As a result, the OpenTelemetry exporter now honors the shared `io.prometheus.exporter.filter.*` configuration, making its behavior consistent with the HTTP/Servlet exporters. --------- Signed-off-by: subhramit <subhramit.bb@live.in>
1 parent 5757c41 commit 9b0ede8

5 files changed

Lines changed: 234 additions & 47 deletions

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‎docs/content/otel/otlp.md‎

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@@ -44,6 +44,9 @@ By default, the `OpenTelemetryExporter` will push metrics every 60 seconds to
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the [OpenTelemetryExporter.Builder][builder-javadoc], or at runtime via
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[`io.prometheus.exporter.opentelemetry.*`][otel-properties] properties.
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The OpenTelemetry exporter also honors the shared [`io.prometheus.exporter.filter.*`][exporter-filter-properties] metric-name
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filter properties.
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In addition to the Prometheus Java client configuration, the exporter also recognizes standard
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OpenTelemetry configuration. For example, you can set
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the [OTEL_EXPORTER_OTLP_METRICS_ENDPOINT](https://opentelemetry.io/docs/concepts/sdk-configuration/otlp-exporter-configuration/#otel_exporter_otlp_metrics_endpoint)
@@ -62,4 +65,5 @@ OTel collector, and a Prometheus server.
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[builder-javadoc]: /client_java/api/io/prometheus/metrics/exporter/opentelemetry/OpenTelemetryExporter.Builder.html
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[opentelemetry-example]: https://github.com/prometheus/client_java/tree/main/examples/example-exporter-opentelemetry
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[otel-pipeline]: /client_java/images/otel-pipeline.png
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[exporter-filter-properties]: {{< relref "../config/config.md#exporter-filter-properties" >}}
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[otel-properties]: {{< relref "../config/config.md#exporter-opentelemetry-properties" >}}

‎prometheus-metrics-exporter-opentelemetry/src/main/java/io/prometheus/metrics/exporter/opentelemetry/OtelAutoConfig.java‎

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@@ -40,8 +40,10 @@ static MetricReader createReader(
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MetricReader reader = requireNonNull(readerRef.get());
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boolean preserveNames = resolvePreserveNames(builder, config);
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reader.register(
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new PrometheusMetricProducer(
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registry, instrumentationScopeInfo, getResourceField(sdk), preserveNames));
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PrometheusMetricProducer.builder(
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registry, instrumentationScopeInfo, getResourceField(sdk), preserveNames)
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.exporterFilterProperties(config.getExporterFilterProperties())
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.build());
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return reader;
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}
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‎prometheus-metrics-exporter-opentelemetry/src/main/java/io/prometheus/metrics/exporter/opentelemetry/PrometheusMetricProducer.java‎

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@@ -7,7 +7,9 @@
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import io.opentelemetry.sdk.metrics.export.CollectionRegistration;
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import io.opentelemetry.sdk.resources.Resource;
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import io.opentelemetry.sdk.resources.ResourceBuilder;
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import io.prometheus.metrics.config.ExporterFilterProperties;
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import io.prometheus.metrics.exporter.opentelemetry.otelmodel.MetricDataFactory;
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import io.prometheus.metrics.model.registry.MetricNameFilter;
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import io.prometheus.metrics.model.registry.PrometheusRegistry;
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import io.prometheus.metrics.model.snapshots.CounterSnapshot;
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import io.prometheus.metrics.model.snapshots.GaugeSnapshot;
@@ -22,6 +24,7 @@
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import java.util.ArrayList;
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import java.util.Collection;
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import java.util.List;
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import java.util.function.Predicate;
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import javax.annotation.Nullable;
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class PrometheusMetricProducer implements CollectionRegistration {
@@ -30,29 +33,65 @@ class PrometheusMetricProducer implements CollectionRegistration {
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private final Resource resource;
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private final InstrumentationScopeInfo instrumentationScopeInfo;
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private final boolean preserveNames;
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@Nullable private final Predicate<String> nameFilter;
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public PrometheusMetricProducer(
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private PrometheusMetricProducer(
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PrometheusRegistry registry,
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InstrumentationScopeInfo instrumentationScopeInfo,
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Resource resource,
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boolean preserveNames) {
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boolean preserveNames,
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@Nullable Predicate<String> nameFilter) {
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this.registry = registry;
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this.instrumentationScopeInfo = instrumentationScopeInfo;
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this.resource = resource;
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this.preserveNames = preserveNames;
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this.nameFilter = nameFilter;
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}
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/**
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* Creates a builder for a producer with no metric name filtering by default, i.e. all metrics in
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* {@code registry} are exported unless filter properties are configured on the builder.
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*/
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static Builder builder(
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PrometheusRegistry registry,
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InstrumentationScopeInfo instrumentationScopeInfo,
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Resource resource,
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boolean preserveNames) {
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return new Builder(registry, instrumentationScopeInfo, resource, preserveNames);
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}
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/**
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* Builds a name filter from {@code io.prometheus.exporter.filter.*} properties, mirroring how
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* {@code PrometheusScrapeHandler} builds its filter for the Servlet/HTTPServer exporters so that
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* filtering config behaves consistently across exporters.
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*
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* <p>OpenTelemetry's own Views API also supports filtering and aggregation, and may be preferable
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* for OpenTelemetry-specific deployments; this filter is intended for users who want the same
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* {@code io.prometheus.exporter.filter.*} config to apply regardless of which exporter they use.
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*
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* @return {@code null} if no filter properties are set, to avoid the overhead of testing every
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* metric name against a filter that matches everything.
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*/
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@Nullable
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private static Predicate<String> makeNameFilter(ExporterFilterProperties props) {
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if (props.getAllowedMetricNames() == null
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&& props.getExcludedMetricNames() == null
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&& props.getAllowedMetricNamePrefixes() == null
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&& props.getExcludedMetricNamePrefixes() == null) {
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return null;
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}
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return MetricNameFilter.builder()
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.nameMustBeEqualTo(props.getAllowedMetricNames())
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.nameMustNotBeEqualTo(props.getExcludedMetricNames())
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.nameMustStartWith(props.getAllowedMetricNamePrefixes())
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.nameMustNotStartWith(props.getExcludedMetricNamePrefixes())
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.build();
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}
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@Override
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public Collection<MetricData> collectAllMetrics() {
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// Note: Currently all metrics from the registry are exported. To add metric filtering
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// similar to the Servlet exporter, one could:
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// 1. Add filter properties to ExporterOpenTelemetryProperties (allowedNames, excludedNames,
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// etc.)
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// 2. Convert these properties to a Predicate<String> using MetricNameFilter.builder()
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// 3. Call registry.scrape(filter) instead of registry.scrape()
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// OpenTelemetry also provides its own Views API for filtering and aggregation, which may be
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// preferred for OpenTelemetry-specific deployments.
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MetricSnapshots snapshots = registry.scrape();
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MetricSnapshots snapshots =
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nameFilter != null ? registry.scrape(nameFilter) : registry.scrape();
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Resource resourceWithTargetInfo = resource.merge(resourceFromTargetInfo(snapshots));
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InstrumentationScopeInfo scopeFromInfo = instrumentationScopeFromOtelScopeInfo(snapshots);
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List<MetricData> result = new ArrayList<>(snapshots.size());
@@ -142,4 +181,37 @@ private void addUnlessNull(List<MetricData> result, @Nullable MetricData data) {
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result.add(data);
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}
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}
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static class Builder {
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private final PrometheusRegistry registry;
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private final Resource resource;
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private final InstrumentationScopeInfo instrumentationScopeInfo;
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private final boolean preserveNames;
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private ExporterFilterProperties filterProperties = ExporterFilterProperties.builder().build();
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private Builder(
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PrometheusRegistry registry,
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InstrumentationScopeInfo instrumentationScopeInfo,
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Resource resource,
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boolean preserveNames) {
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this.registry = registry;
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this.instrumentationScopeInfo = instrumentationScopeInfo;
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this.resource = resource;
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this.preserveNames = preserveNames;
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}
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Builder exporterFilterProperties(ExporterFilterProperties filterProperties) {
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this.filterProperties = filterProperties;
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return this;
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}
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PrometheusMetricProducer build() {
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return new PrometheusMetricProducer(
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registry,
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instrumentationScopeInfo,
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resource,
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preserveNames,
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makeNameFilter(filterProperties));
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}
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}
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}

‎prometheus-metrics-exporter-opentelemetry/src/test/java/io/prometheus/metrics/exporter/opentelemetry/ExportTest.java‎

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@@ -12,6 +12,7 @@
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import io.opentelemetry.sdk.testing.assertj.OpenTelemetryAssertions;
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import io.opentelemetry.sdk.testing.exporter.InMemoryMetricReader;
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import io.opentelemetry.sdk.testing.junit5.OpenTelemetryExtension;
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import io.prometheus.metrics.config.ExporterFilterProperties;
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import io.prometheus.metrics.core.metrics.Counter;
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import io.prometheus.metrics.core.metrics.Gauge;
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import io.prometheus.metrics.core.metrics.Histogram;
@@ -46,11 +47,12 @@ void setUp() throws IllegalAccessException, NoSuchFieldException {
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MetricReader reader = (MetricReader) field.get(testing);
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PrometheusMetricProducer prometheusMetricProducer =
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new PrometheusMetricProducer(
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registry,
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InstrumentationScopeInfo.create("test"),
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Resource.create(Attributes.builder().put("staticRes", "value").build()),
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false);
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PrometheusMetricProducer.builder(
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registry,
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InstrumentationScopeInfo.create("test"),
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Resource.create(Attributes.builder().put("staticRes", "value").build()),
54+
false)
55+
.build();
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5557
reader.register(prometheusMetricProducer);
5658
}
@@ -332,11 +334,12 @@ void preserveNamesWithUnit() {
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InMemoryMetricReader reader = InMemoryMetricReader.create();
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PrometheusRegistry preserveRegistry = new PrometheusRegistry();
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reader.register(
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new PrometheusMetricProducer(
336-
preserveRegistry,
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InstrumentationScopeInfo.create("test"),
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Resource.create(Attributes.builder().put("staticRes", "value").build()),
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true));
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PrometheusMetricProducer.builder(
338+
preserveRegistry,
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InstrumentationScopeInfo.create("test"),
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Resource.create(Attributes.builder().put("staticRes", "value").build()),
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true)
342+
.build());
340343

341344
Counter.builder().name("req").unit(Unit.BYTES).register(preserveRegistry).inc();
342345

@@ -350,11 +353,12 @@ void preserveNamesWithUnitAlreadyInName() {
350353
InMemoryMetricReader reader = InMemoryMetricReader.create();
351354
PrometheusRegistry preserveRegistry = new PrometheusRegistry();
352355
reader.register(
353-
new PrometheusMetricProducer(
354-
preserveRegistry,
355-
InstrumentationScopeInfo.create("test"),
356-
Resource.create(Attributes.builder().put("staticRes", "value").build()),
357-
true));
356+
PrometheusMetricProducer.builder(
357+
preserveRegistry,
358+
InstrumentationScopeInfo.create("test"),
359+
Resource.create(Attributes.builder().put("staticRes", "value").build()),
360+
true)
361+
.build());
358362

359363
Counter.builder().name("req_bytes").unit(Unit.BYTES).register(preserveRegistry).inc();
360364

@@ -368,11 +372,12 @@ void preserveNamesWithoutUnit() {
368372
InMemoryMetricReader reader = InMemoryMetricReader.create();
369373
PrometheusRegistry preserveRegistry = new PrometheusRegistry();
370374
reader.register(
371-
new PrometheusMetricProducer(
372-
preserveRegistry,
373-
InstrumentationScopeInfo.create("test"),
374-
Resource.create(Attributes.builder().put("staticRes", "value").build()),
375-
true));
375+
PrometheusMetricProducer.builder(
376+
preserveRegistry,
377+
InstrumentationScopeInfo.create("test"),
378+
Resource.create(Attributes.builder().put("staticRes", "value").build()),
379+
true)
380+
.build());
376381

377382
Counter.builder().name("events_total").register(preserveRegistry).inc();
378383

@@ -381,6 +386,50 @@ void preserveNamesWithoutUnit() {
381386
OpenTelemetryAssertions.assertThat(metrics.get(0)).hasName("events_total");
382387
}
383388

389+
@Test
390+
void metricNameFilterExcludedNames() {
391+
InMemoryMetricReader reader = InMemoryMetricReader.create();
392+
PrometheusRegistry filteredRegistry = new PrometheusRegistry();
393+
reader.register(
394+
PrometheusMetricProducer.builder(
395+
filteredRegistry,
396+
InstrumentationScopeInfo.create("test"),
397+
Resource.create(Attributes.builder().put("staticRes", "value").build()),
398+
false)
399+
.exporterFilterProperties(
400+
ExporterFilterProperties.builder().excludedNames("secret_total").build())
401+
.build());
402+
403+
Counter.builder().name("secret").register(filteredRegistry).inc();
404+
Counter.builder().name("public").register(filteredRegistry).inc();
405+
406+
List<MetricData> metrics = new ArrayList<>(reader.collectAllMetrics());
407+
assertThat(metrics).hasSize(1);
408+
OpenTelemetryAssertions.assertThat(metrics.get(0)).hasName("public");
409+
}
410+
411+
@Test
412+
void metricNameFilterAllowedPrefixes() {
413+
InMemoryMetricReader reader = InMemoryMetricReader.create();
414+
PrometheusRegistry filteredRegistry = new PrometheusRegistry();
415+
reader.register(
416+
PrometheusMetricProducer.builder(
417+
filteredRegistry,
418+
InstrumentationScopeInfo.create("test"),
419+
Resource.create(Attributes.builder().put("staticRes", "value").build()),
420+
false)
421+
.exporterFilterProperties(
422+
ExporterFilterProperties.builder().allowedPrefixes("http_").build())
423+
.build());
424+
425+
Counter.builder().name("http_requests").register(filteredRegistry).inc();
426+
Counter.builder().name("jvm_threads").register(filteredRegistry).inc();
427+
428+
List<MetricData> metrics = new ArrayList<>(reader.collectAllMetrics());
429+
assertThat(metrics).hasSize(1);
430+
OpenTelemetryAssertions.assertThat(metrics.get(0)).hasName("http_requests");
431+
}
432+
384433
private MetricAssert metricAssert() {
385434
List<MetricData> metrics = testing.getMetrics();
386435
assertThat(metrics).hasSize(1);

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