Add armeria-prometheus1 module for Prometheus version 1 and deprecate older classes.

core/build.gradle

@@ -105,9 +105,9 @@ dependencies {
 
     // Micrometer and other metric-related stuff
     api libs.micrometer.core
-    optionalApi libs.micrometer.prometheus
+    optionalApi libs.micrometer.prometheus.legacy
     optionalApi libs.dropwizard.metrics.core
-    optionalApi libs.prometheus
+    optionalApi libs.prometheus.legacy
 
     // Netty
     api libs.netty.transport
@@ -154,6 +154,8 @@ dependencies {
     // Jetty, for testing interoperability with other servers.
     testImplementation libs.jetty94.webapp
 
+    testImplementation project(':prometheus1')
+
     // Brotli
     implementation libs.brotli4j
     optionalImplementation libs.brotli4j.linux

core/src/main/java/com/linecorp/armeria/common/metric/PrometheusMeterRegistries.java

@@ -27,7 +27,10 @@
 /**
  * Provides the convenient factory methods for {@link PrometheusMeterRegistry} with more sensible defaults for
  * {@link NamingConvention}.
+ *
+ * @deprecated Use {@code PrometheusMeterRegistries} in {@code armeria-prometheus1} module instead.
  */
+@Deprecated
 public final class PrometheusMeterRegistries {
 
     private static final PrometheusMeterRegistry defaultRegistry =

core/src/main/java/com/linecorp/armeria/server/metric/PrometheusExpositionService.java

@@ -42,7 +42,10 @@
 /**
  * Exposes Prometheus metrics in <a href="https://prometheus.io/docs/instrumenting/exposition_formats/">text
  * format 0.0.4 or OpenMetrics format</a>.
+ *
+ * @deprecated Use {@code PrometheusExpositionService} in {@code armeria-prometheus1} module instead.
  */
+@Deprecated
 public final class PrometheusExpositionService extends AbstractHttpService implements TransientHttpService {
 
     /**
@@ -106,7 +109,7 @@ protected HttpResponse doGet(ServiceRequestContext ctx, HttpRequest req) throws
         final ByteBuf buffer = ctx.alloc().buffer();
         boolean success = false;
         try (ByteBufOutputStream byteBufOutputStream = new ByteBufOutputStream(buffer);
-            OutputStreamWriter writer = new OutputStreamWriter(byteBufOutputStream)) {
+             OutputStreamWriter writer = new OutputStreamWriter(byteBufOutputStream)) {
             TextFormat.writeFormat(format, writer, collectorRegistry.metricFamilySamples());
             success = true;
         } finally {

core/src/main/java/com/linecorp/armeria/server/metric/PrometheusExpositionServiceBuilder.java

@@ -25,7 +25,10 @@
 
 /**
  * Builds a {@link PrometheusExpositionService}.
+ *
+ * @deprecated Use {@code PrometheusExpositionServiceBuilder} in {@code armeria-prometheus1} module instead.
  */
+@Deprecated
 public final class PrometheusExpositionServiceBuilder implements TransientServiceBuilder {
 
     private final CollectorRegistry collectorRegistry;

core/src/test/java/com/linecorp/armeria/client/ConnectionPoolCollectingMetricTest.java

@@ -24,7 +24,7 @@
 
 import com.linecorp.armeria.common.SessionProtocol;
 import com.linecorp.armeria.common.metric.MoreMeters;
-import com.linecorp.armeria.common.metric.PrometheusMeterRegistries;
+import com.linecorp.armeria.common.prometheus.PrometheusMeterRegistries;
 
 import io.micrometer.core.instrument.MeterRegistry;
 import io.netty.util.AttributeMap;

core/src/test/java/com/linecorp/armeria/client/RefreshingAddressResolverTest.java

@@ -52,7 +52,7 @@
 import com.linecorp.armeria.client.endpoint.dns.TestDnsServer;
 import com.linecorp.armeria.client.retry.Backoff;
 import com.linecorp.armeria.common.annotation.Nullable;
-import com.linecorp.armeria.common.metric.PrometheusMeterRegistries;
+import com.linecorp.armeria.common.prometheus.PrometheusMeterRegistries;
 import com.linecorp.armeria.internal.client.dns.ByteArrayDnsRecord;
 import com.linecorp.armeria.internal.client.dns.DnsQuestionWithoutTrailingDot;
 import com.linecorp.armeria.testing.junit5.common.EventLoopExtension;

core/src/test/java/com/linecorp/armeria/client/circuitbreaker/MetricCollectingCircuitBreakerListenerTest.java

@@ -21,7 +21,7 @@
 import org.junit.jupiter.api.Test;
 
 import com.linecorp.armeria.common.metric.MoreMeters;
-import com.linecorp.armeria.common.metric.PrometheusMeterRegistries;
+import com.linecorp.armeria.common.prometheus.PrometheusMeterRegistries;
 
 import io.micrometer.core.instrument.MeterRegistry;
 

core/src/test/java/com/linecorp/armeria/client/endpoint/healthcheck/HealthCheckedEndpointGroupIntegrationTest.java

@@ -36,7 +36,7 @@
 import com.linecorp.armeria.client.logging.LoggingClient;
 import com.linecorp.armeria.common.SessionProtocol;
 import com.linecorp.armeria.common.metric.MoreMeters;
-import com.linecorp.armeria.common.metric.PrometheusMeterRegistries;
+import com.linecorp.armeria.common.prometheus.PrometheusMeterRegistries;
 import com.linecorp.armeria.server.ServerBuilder;
 import com.linecorp.armeria.server.healthcheck.HealthCheckService;
 import com.linecorp.armeria.testing.junit5.server.ServerExtension;

core/src/test/java/com/linecorp/armeria/common/metric/DropwizardMeterRegistriesTest.java

@@ -21,23 +21,26 @@
 import static org.assertj.core.api.Assertions.fail;
 
 import java.time.Duration;
-import java.util.Enumeration;
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 
 import org.junit.jupiter.api.Test;
 
 import com.codahale.metrics.MetricRegistry;
-import com.google.common.collect.ImmutableList;
+
+import com.linecorp.armeria.common.prometheus.PrometheusMeterRegistries;
 
 import io.micrometer.core.instrument.Clock;
 import io.micrometer.core.instrument.DistributionSummary;
 import io.micrometer.core.instrument.Timer;
 import io.micrometer.core.instrument.composite.CompositeMeterRegistry;
 import io.micrometer.core.instrument.dropwizard.DropwizardMeterRegistry;
-import io.micrometer.prometheus.PrometheusMeterRegistry;
-import io.prometheus.client.Collector.MetricFamilySamples;
-import io.prometheus.client.Collector.MetricFamilySamples.Sample;
+import io.micrometer.prometheusmetrics.PrometheusMeterRegistry;
+import io.prometheus.metrics.model.snapshots.DataPointSnapshot;
+import io.prometheus.metrics.model.snapshots.MetricMetadata;
+import io.prometheus.metrics.model.snapshots.MetricSnapshot;
+import io.prometheus.metrics.model.snapshots.SummarySnapshot.SummaryDataPointSnapshot;
 
 class DropwizardMeterRegistriesTest {
     @Test
@@ -131,24 +134,33 @@ void filteredGaugesDoNotAffectOthers() {
         assertThat(dropwizard.getDropwizardRegistry().getMetrics()).containsOnlyKeys("summary");
 
         // Make sure Prometheus registry collects all samples.
-        final MetricFamilySamples prometheusSamples = findPrometheusSample(prometheus, "summary");
-        assertThat(prometheusSamples.samples).containsExactly(
-                new Sample("summary", ImmutableList.of("quantile"), ImmutableList.of("0.5"), 42),
-                new Sample("summary", ImmutableList.of("quantile"), ImmutableList.of("0.99"), 42),
-                new Sample("summary_count", ImmutableList.of(), ImmutableList.of(), 1),
-                new Sample("summary_sum", ImmutableList.of(), ImmutableList.of(), 42));
+        final List<? extends DataPointSnapshot> dataPointSnapshots =
+                findPrometheusDataPointSnapshot(prometheus, "summary");
+        assertThat(dataPointSnapshots.size()).isOne();
+        final DataPointSnapshot snapshot = dataPointSnapshots.get(0);
+        assertThat(snapshot).isInstanceOf(SummaryDataPointSnapshot.class);
+        // SummaryDataPointSnapshot and its values do not override equals().
+        final SummaryDataPointSnapshot summarySnapshot = (SummaryDataPointSnapshot) snapshot;
+        assertThat(summarySnapshot.getCount()).isOne();
+        assertThat(summarySnapshot.getSum()).isEqualTo(42.0);
+        assertThat(summarySnapshot.getQuantiles().size()).isEqualTo(2);
+        assertThat(summarySnapshot.getQuantiles().get(0).getQuantile()).isEqualTo(0.5);
+        assertThat(summarySnapshot.getQuantiles().get(0).getValue()).isEqualTo(42.0);
+        assertThat(summarySnapshot.getQuantiles().get(1).getQuantile()).isEqualTo(0.99);
+        assertThat(summarySnapshot.getQuantiles().get(1).getValue()).isEqualTo(42.0);
     }
 
-    private static MetricFamilySamples findPrometheusSample(PrometheusMeterRegistry registry, String name) {
-        for (final Enumeration<MetricFamilySamples> e = registry.getPrometheusRegistry().metricFamilySamples();
-             e.hasMoreElements();) {
-            final MetricFamilySamples samples = e.nextElement();
-            if (name.equals(samples.name)) {
-                return samples;
+    private static List<? extends DataPointSnapshot> findPrometheusDataPointSnapshot(
+            PrometheusMeterRegistry registry, String name) {
+        for (final MetricSnapshot snapshot : registry.getPrometheusRegistry().scrape()) {
+            final MetricMetadata metadata = snapshot.getMetadata();
+            if (name.equals(metadata.getName())) {
+                return snapshot.getDataPoints();
             }
         }
 
         fail("Could not find a Prometheus sample: " + name);
         throw new Error(); // Never reaches here.
     }
 }
+

core/src/test/java/com/linecorp/armeria/common/metric/MeterIdPrefixFunctionTest.java

@@ -31,6 +31,7 @@
 import com.linecorp.armeria.common.annotation.Nullable;
 import com.linecorp.armeria.common.logging.RequestLog;
 import com.linecorp.armeria.common.logging.RequestOnlyLog;
+import com.linecorp.armeria.common.prometheus.PrometheusMeterRegistries;
 import com.linecorp.armeria.server.ServiceRequestContext;
 
 import io.micrometer.core.instrument.MeterRegistry;

core/src/test/java/com/linecorp/armeria/internal/common/metric/CaffeineMetricSupportTest.java

@@ -39,7 +39,7 @@
 
 import com.linecorp.armeria.common.metric.MeterIdPrefix;
 import com.linecorp.armeria.common.metric.MoreMeters;
-import com.linecorp.armeria.common.metric.PrometheusMeterRegistries;
+import com.linecorp.armeria.common.prometheus.PrometheusMeterRegistries;
 
 import io.micrometer.core.instrument.MeterRegistry;
 

core/src/test/java/com/linecorp/armeria/internal/common/metric/MicrometerUtilTest.java

@@ -22,7 +22,7 @@
 import org.junit.jupiter.api.Test;
 
 import com.linecorp.armeria.common.metric.MeterIdPrefix;
-import com.linecorp.armeria.common.metric.PrometheusMeterRegistries;
+import com.linecorp.armeria.common.prometheus.PrometheusMeterRegistries;
 
 import io.micrometer.core.instrument.MeterRegistry;
 

core/src/test/java/com/linecorp/armeria/internal/common/metric/RequestMetricSupportTest.java

@@ -33,7 +33,7 @@
 import com.linecorp.armeria.common.SuccessFunction;
 import com.linecorp.armeria.common.logging.ClientConnectionTimings;
 import com.linecorp.armeria.common.metric.MeterIdPrefixFunction;
-import com.linecorp.armeria.common.metric.PrometheusMeterRegistries;
+import com.linecorp.armeria.common.prometheus.PrometheusMeterRegistries;
 import com.linecorp.armeria.common.util.SafeCloseable;
 import com.linecorp.armeria.internal.testing.ImmediateEventLoop;
 import com.linecorp.armeria.server.RequestTimeoutException;

core/src/test/java/com/linecorp/armeria/server/ServerBuilderTest.java

@@ -52,7 +52,7 @@
 import com.linecorp.armeria.common.HttpResponse;
 import com.linecorp.armeria.common.HttpStatus;
 import com.linecorp.armeria.common.SessionProtocol;
-import com.linecorp.armeria.common.metric.PrometheusMeterRegistries;
+import com.linecorp.armeria.common.prometheus.PrometheusMeterRegistries;
 import com.linecorp.armeria.common.util.DomainSocketAddress;
 import com.linecorp.armeria.common.util.TransportType;
 import com.linecorp.armeria.internal.common.util.MinifiedBouncyCastleProvider;
@@ -61,7 +61,7 @@
 import com.linecorp.armeria.testing.junit5.server.ServerExtension;
 
 import io.micrometer.core.instrument.Metrics;
-import io.micrometer.prometheus.PrometheusMeterRegistry;
+import io.micrometer.prometheusmetrics.PrometheusMeterRegistry;
 import io.netty.channel.ChannelOption;
 import io.netty.handler.ssl.SslContextBuilder;
 import reactor.core.scheduler.Schedulers;

core/src/test/java/com/linecorp/armeria/server/ServerListenerTest.java

@@ -34,7 +34,7 @@
 import org.junit.jupiter.params.provider.ArgumentsSource;
 
 import com.linecorp.armeria.common.HttpResponse;
-import com.linecorp.armeria.common.metric.PrometheusMeterRegistries;
+import com.linecorp.armeria.common.prometheus.PrometheusMeterRegistries;
 import com.linecorp.armeria.testing.junit5.server.ServerExtension;
 
 class ServerListenerTest {

core/src/test/java/com/linecorp/armeria/server/ServerTest.java

@@ -69,7 +69,7 @@
 import com.linecorp.armeria.common.ResponseHeaders;
 import com.linecorp.armeria.common.SessionProtocol;
 import com.linecorp.armeria.common.metric.MeterIdPrefix;
-import com.linecorp.armeria.common.metric.PrometheusMeterRegistries;
+import com.linecorp.armeria.common.prometheus.PrometheusMeterRegistries;
 import com.linecorp.armeria.common.util.CompletionActions;
 import com.linecorp.armeria.common.util.Exceptions;
 import com.linecorp.armeria.common.util.ThreadFactories;

core/src/test/java/com/linecorp/armeria/server/ServerTlsCertificateMetricsTest.java

@@ -27,7 +27,7 @@
 import org.junit.jupiter.api.Test;
 
 import com.linecorp.armeria.common.HttpResponse;
-import com.linecorp.armeria.common.metric.PrometheusMeterRegistries;
+import com.linecorp.armeria.common.prometheus.PrometheusMeterRegistries;
 import com.linecorp.armeria.internal.common.util.SelfSignedCertificate;
 
 import io.micrometer.core.instrument.Gauge;

core/src/test/java/com/linecorp/armeria/server/ServerTlsHandshakeMetricsTest.java

@@ -35,7 +35,7 @@
 import com.linecorp.armeria.common.HttpStatus;
 import com.linecorp.armeria.common.SessionProtocol;
 import com.linecorp.armeria.common.metric.MoreMeters;
-import com.linecorp.armeria.common.metric.PrometheusMeterRegistries;
+import com.linecorp.armeria.common.prometheus.PrometheusMeterRegistries;
 import com.linecorp.armeria.testing.junit5.server.ServerExtension;
 
 import io.micrometer.core.instrument.Counter;

core/src/test/java/com/linecorp/armeria/server/logging/ContentPreviewerCancellationTest.java

@@ -39,7 +39,7 @@
 import com.linecorp.armeria.common.annotation.Nullable;
 import com.linecorp.armeria.common.logging.ContentPreviewerFactory;
 import com.linecorp.armeria.common.metric.MeterIdPrefixFunction;
-import com.linecorp.armeria.common.metric.PrometheusMeterRegistries;
+import com.linecorp.armeria.common.prometheus.PrometheusMeterRegistries;
 import com.linecorp.armeria.common.stream.CancelledSubscriptionException;
 import com.linecorp.armeria.common.util.Functions;
 import com.linecorp.armeria.internal.logging.ContentPreviewingUtil;
@@ -51,10 +51,10 @@
 import com.linecorp.armeria.server.annotation.Get;
 import com.linecorp.armeria.server.cors.CorsService;
 import com.linecorp.armeria.server.metric.MetricCollectingService;
-import com.linecorp.armeria.server.metric.PrometheusExpositionService;
+import com.linecorp.armeria.server.prometheus.PrometheusExpositionService;
 import com.linecorp.armeria.testing.junit5.server.ServerExtension;
 
-import io.micrometer.prometheus.PrometheusMeterRegistry;
+import io.micrometer.prometheusmetrics.PrometheusMeterRegistry;
 
 class ContentPreviewerCancellationTest {
 
@@ -77,7 +77,8 @@ protected void configure(ServerBuilder sb) {
                               .newDecorator()
               )
               .annotatedService(new TestService())
-              .service("/metrics", PrometheusExpositionService.of(registry.getPrometheusRegistry()));
+              .service("/metrics",
+                       PrometheusExpositionService.of(registry.getPrometheusRegistry()));
         }
     };
 

core/src/test/java/com/linecorp/armeria/server/metric/MetricCollectingServiceTest.java

@@ -27,11 +27,11 @@
 
 import com.linecorp.armeria.common.HttpResponse;
 import com.linecorp.armeria.common.metric.MeterIdPrefixFunction;
-import com.linecorp.armeria.common.metric.PrometheusMeterRegistries;
+import com.linecorp.armeria.common.prometheus.PrometheusMeterRegistries;
 import com.linecorp.armeria.server.ServerBuilder;
 import com.linecorp.armeria.testing.junit5.server.ServerExtension;
 
-import io.micrometer.prometheus.PrometheusMeterRegistry;
+import io.micrometer.prometheusmetrics.PrometheusMeterRegistry;
 
 class MetricCollectingServiceTest {
 

core/src/test/java/com/linecorp/armeria/server/metric/PrometheusExpositionServiceTest.java

@@ -130,9 +130,9 @@ class FormatTest {
         void prometheusRequestsPrometheusFormat() throws InterruptedException {
             final WebClient client = WebClient.of(server.httpUri());
             final HttpRequest request = HttpRequest.builder()
-                    .get("/enabled")
-                    .header(HttpHeaderNames.ACCEPT, TextFormat.CONTENT_TYPE_004)
-                    .build();
+                                                   .get("/enabled")
+                                                   .header(HttpHeaderNames.ACCEPT, TextFormat.CONTENT_TYPE_004)
+                                                   .build();
             final AggregatedHttpResponse response = client.execute(request).aggregate().join();
             assertThat(response.headers().get(HttpHeaderNames.CONTENT_TYPE))
                     .isEqualTo(TextFormat.CONTENT_TYPE_004);
@@ -142,9 +142,10 @@ void prometheusRequestsPrometheusFormat() throws InterruptedException {
         void prometheusRequestsOpenMetricsFormat() throws InterruptedException {
             final WebClient client = WebClient.of(server.httpUri());
             final HttpRequest request = HttpRequest.builder()
-                    .get("/enabled")
-                    .header(HttpHeaderNames.ACCEPT, TextFormat.CONTENT_TYPE_OPENMETRICS_100)
-                    .build();
+                                                   .get("/enabled")
+                                                   .header(HttpHeaderNames.ACCEPT,
+                                                           TextFormat.CONTENT_TYPE_OPENMETRICS_100)
+                                                   .build();
             final AggregatedHttpResponse response = client.execute(request).aggregate().join();
             assertThat(response.headers().get(HttpHeaderNames.CONTENT_TYPE))
                     .isEqualTo(TextFormat.CONTENT_TYPE_OPENMETRICS_100);