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feat: Add OpenMetrics2 enabled flag #1953

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Merged
zeitlinger merged 1 commit into from
Mar 18, 2026
Merged

feat: Add OpenMetrics2 enabled flag #1953

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25 changes: 23 additions & 2 deletions ...eus-metrics-config/src/main/java/io/prometheus/metrics/config/OpenMetrics2Properties.java
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Original file line number Diff line number Diff line change
Expand Up @@ -9,27 +9,39 @@
public class OpenMetrics2Properties {

private static final String PREFIX = "io.prometheus.openmetrics2";
private static final String ENABLED = "enabled";
private static final String CONTENT_NEGOTIATION = "content_negotiation";
private static final String COMPOSITE_VALUES = "composite_values";
private static final String EXEMPLAR_COMPLIANCE = "exemplar_compliance";
private static final String NATIVE_HISTOGRAMS = "native_histograms";

@Nullable private final Boolean enabled;
@Nullable private final Boolean contentNegotiation;
@Nullable private final Boolean compositeValues;
@Nullable private final Boolean exemplarCompliance;
@Nullable private final Boolean nativeHistograms;

private OpenMetrics2Properties(
@Nullable Boolean enabled,
@Nullable Boolean contentNegotiation,
@Nullable Boolean compositeValues,
@Nullable Boolean exemplarCompliance,
@Nullable Boolean nativeHistograms) {
this.enabled = enabled;
this.contentNegotiation = contentNegotiation;
this.compositeValues = compositeValues;
this.exemplarCompliance = exemplarCompliance;
this.nativeHistograms = nativeHistograms;
}

/**
* Enable the OpenMetrics 2.0 text format writer. When {@code true}, the OM2 writer is used
* instead of OM1 for OpenMetrics responses. Default is {@code false}.
*/
public boolean getEnabled() {
return enabled != null && enabled;
}

/** Gate OM2 features behind content negotiation. Default is {@code false}. */
public boolean getContentNegotiation() {
return contentNegotiation != null && contentNegotiation;
Expand All @@ -56,12 +68,13 @@ public boolean getNativeHistograms() {
*/
static OpenMetrics2Properties load(PropertySource propertySource)
throws PrometheusPropertiesException {
Boolean enabled = Util.loadBoolean(PREFIX, ENABLED, propertySource);
Boolean contentNegotiation = Util.loadBoolean(PREFIX, CONTENT_NEGOTIATION, propertySource);
Boolean compositeValues = Util.loadBoolean(PREFIX, COMPOSITE_VALUES, propertySource);
Boolean exemplarCompliance = Util.loadBoolean(PREFIX, EXEMPLAR_COMPLIANCE, propertySource);
Boolean nativeHistograms = Util.loadBoolean(PREFIX, NATIVE_HISTOGRAMS, propertySource);
return new OpenMetrics2Properties(
contentNegotiation, compositeValues, exemplarCompliance, nativeHistograms);
enabled, contentNegotiation, compositeValues, exemplarCompliance, nativeHistograms);
}

public static Builder builder() {
Expand All @@ -70,13 +83,20 @@ public static Builder builder() {

public static class Builder {

@Nullable private Boolean enabled;
@Nullable private Boolean contentNegotiation;
@Nullable private Boolean compositeValues;
@Nullable private Boolean exemplarCompliance;
@Nullable private Boolean nativeHistograms;

private Builder() {}

/** See {@link #getEnabled()} */
public Builder enabled(boolean enabled) {
this.enabled = enabled;
return this;
}

/** See {@link #getContentNegotiation()} */
public Builder contentNegotiation(boolean contentNegotiation) {
this.contentNegotiation = contentNegotiation;
Expand All @@ -103,6 +123,7 @@ public Builder nativeHistograms(boolean nativeHistograms) {

/** Enable all OpenMetrics 2.0 features */
public Builder enableAll() {
this.enabled = true;
this.contentNegotiation = true;
this.compositeValues = true;
this.exemplarCompliance = true;
Expand All @@ -112,7 +133,7 @@ public Builder enableAll() {

public OpenMetrics2Properties build() {
return new OpenMetrics2Properties(
contentNegotiation, compositeValues, exemplarCompliance, nativeHistograms);
enabled, contentNegotiation, compositeValues, exemplarCompliance, nativeHistograms);
}
}
}
3 changes: 2 additions & 1 deletion ...theus-metrics-config/src/main/java/io/prometheus/metrics/config/PrometheusProperties.java
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Original file line number Diff line number Diff line change
Expand Up @@ -242,7 +242,8 @@ public Builder exporterOpenTelemetryProperties(
}

public Builder enableOpenMetrics2(Consumer<OpenMetrics2Properties.Builder> configurator) {
OpenMetrics2Properties.Builder openMetrics2Builder = OpenMetrics2Properties.builder();
OpenMetrics2Properties.Builder openMetrics2Builder =
OpenMetrics2Properties.builder().enabled(true);
configurator.accept(openMetrics2Builder);
this.openMetrics2Properties = openMetrics2Builder.build();
return this;
Expand Down
12 changes: 12 additions & 0 deletions ...metrics-config/src/test/java/io/prometheus/metrics/config/OpenMetrics2PropertiesTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,8 @@ void load() {
load(
new HashMap<>(
Map.of(
"io.prometheus.openmetrics2.enabled",
"true",
"io.prometheus.openmetrics2.content_negotiation",
"true",
"io.prometheus.openmetrics2.composite_values",
Expand All @@ -23,6 +25,7 @@ void load() {
"true",
"io.prometheus.openmetrics2.native_histograms",
"true")));
assertThat(properties.getEnabled()).isTrue();
assertThat(properties.getContentNegotiation()).isTrue();
assertThat(properties.getCompositeValues()).isTrue();
assertThat(properties.getExemplarCompliance()).isTrue();
Expand All @@ -31,6 +34,11 @@ void load() {

@Test
void loadInvalidValue() {
assertThatExceptionOfType(PrometheusPropertiesException.class)
.isThrownBy(
() -> load(new HashMap<>(Map.of("io.prometheus.openmetrics2.enabled", "invalid"))))
.withMessage(
"io.prometheus.openmetrics2.enabled: Expecting 'true' or 'false'. Found: invalid");
assertThatExceptionOfType(PrometheusPropertiesException.class)
.isThrownBy(
() ->
Expand Down Expand Up @@ -79,11 +87,13 @@ private static OpenMetrics2Properties load(Map<String, String> map) {
void builder() {
OpenMetrics2Properties properties =
OpenMetrics2Properties.builder()
.enabled(true)
.contentNegotiation(true)
.compositeValues(false)
.exemplarCompliance(true)
.nativeHistograms(false)
.build();
assertThat(properties.getEnabled()).isTrue();
assertThat(properties.getContentNegotiation()).isTrue();
assertThat(properties.getCompositeValues()).isFalse();
assertThat(properties.getExemplarCompliance()).isTrue();
Expand All @@ -93,6 +103,7 @@ void builder() {
@Test
void builderEnableAll() {
OpenMetrics2Properties properties = OpenMetrics2Properties.builder().enableAll().build();
assertThat(properties.getEnabled()).isTrue();
assertThat(properties.getContentNegotiation()).isTrue();
assertThat(properties.getCompositeValues()).isTrue();
assertThat(properties.getExemplarCompliance()).isTrue();
Expand All @@ -102,6 +113,7 @@ void builderEnableAll() {
@Test
void defaultValues() {
OpenMetrics2Properties properties = OpenMetrics2Properties.builder().build();
assertThat(properties.getEnabled()).isFalse();
assertThat(properties.getContentNegotiation()).isFalse();
assertThat(properties.getCompositeValues()).isFalse();
assertThat(properties.getExemplarCompliance()).isFalse();
Expand Down
6 changes: 1 addition & 5 deletions ...-textformats/src/main/java/io/prometheus/metrics/expositionformats/ExpositionFormats.java
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Expand Up @@ -76,11 +76,7 @@ public ExpositionFormatWriter findWriter(@Nullable String acceptHeader) {
}

private boolean isOpenMetrics2Enabled() {
OpenMetrics2Properties props = openMetrics2TextFormatWriter.getOpenMetrics2Properties();
return props.getContentNegotiation()
|| props.getCompositeValues()
|| props.getExemplarCompliance()
|| props.getNativeHistograms();
return openMetrics2TextFormatWriter.getOpenMetrics2Properties().getEnabled();
}

public PrometheusProtobufWriter getPrometheusProtobufWriter() {
Expand Down
44 changes: 9 additions & 35 deletions ...tformats/src/test/java/io/prometheus/metrics/expositionformats/ExpositionFormatsTest.java
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Expand Up @@ -119,77 +119,51 @@ void testOM2DisabledByDefault() {
}

@Test
void testOM2EnabledWithContentNegotiation() {
void testOM2EnabledOnly() {
PrometheusProperties props =
PrometheusProperties.builder()
.openMetrics2Properties(
OpenMetrics2Properties.builder().contentNegotiation(true).build())
.openMetrics2Properties(OpenMetrics2Properties.builder().enabled(true).build())
.build();
ExpositionFormats formats = ExpositionFormats.init(props);
ExpositionFormatWriter writer = formats.findWriter("application/openmetrics-text");
// When contentNegotiation is enabled, should return OM2 writer
assertThat(writer).isInstanceOf(OpenMetrics2TextFormatWriter.class);
}

@Test
void testOM2EnabledWithCompositeValues() {
PrometheusProperties props =
PrometheusProperties.builder()
.openMetrics2Properties(OpenMetrics2Properties.builder().compositeValues(true).build())
.build();
ExpositionFormats formats = ExpositionFormats.init(props);
ExpositionFormatWriter writer = formats.findWriter("application/openmetrics-text");
assertThat(writer).isInstanceOf(OpenMetrics2TextFormatWriter.class);
}

@Test
void testOM2EnabledWithExemplarCompliance() {
void testOM2NotEnabledByFeatureFlagAlone() {
// Feature flags without enabled=true should not activate the OM2 writer
PrometheusProperties props =
PrometheusProperties.builder()
.openMetrics2Properties(
OpenMetrics2Properties.builder().exemplarCompliance(true).build())
.build();
ExpositionFormats formats = ExpositionFormats.init(props);
ExpositionFormatWriter writer = formats.findWriter("application/openmetrics-text");
// When exemplarCompliance is enabled, should return OM2 writer
assertThat(writer).isInstanceOf(OpenMetrics2TextFormatWriter.class);
}

@Test
void testOM2EnabledWithNativeHistograms() {
PrometheusProperties props =
PrometheusProperties.builder()
.openMetrics2Properties(OpenMetrics2Properties.builder().nativeHistograms(true).build())
OpenMetrics2Properties.builder().contentNegotiation(true).build())
.build();
ExpositionFormats formats = ExpositionFormats.init(props);
ExpositionFormatWriter writer = formats.findWriter("application/openmetrics-text");
// When nativeHistograms is enabled, should return OM2 writer
assertThat(writer).isInstanceOf(OpenMetrics2TextFormatWriter.class);
assertThat(writer).isInstanceOf(OpenMetricsTextFormatWriter.class);
}

@Test
void testOM2EnabledWithMultipleFlags() {
void testOM2EnabledWithFeatureFlags() {
PrometheusProperties props =
PrometheusProperties.builder()
.openMetrics2Properties(
OpenMetrics2Properties.builder()
.enabled(true)
.contentNegotiation(true)
.compositeValues(true)
.nativeHistograms(true)
.build())
.build();
ExpositionFormats formats = ExpositionFormats.init(props);
ExpositionFormatWriter writer = formats.findWriter("application/openmetrics-text");
// When multiple OM2 flags are enabled, should return OM2 writer
assertThat(writer).isInstanceOf(OpenMetrics2TextFormatWriter.class);
}

@Test
void testProtobufWriterTakesPrecedence() {
PrometheusProperties props =
PrometheusProperties.builder()
.openMetrics2Properties(
OpenMetrics2Properties.builder().contentNegotiation(true).build())
.openMetrics2Properties(OpenMetrics2Properties.builder().enabled(true).build())
.build();
ExpositionFormats formats = ExpositionFormats.init(props);
ExpositionFormatWriter writer =
Expand Down
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