Add armeria-prometheus1 module for Prometheus version 1 and deprecate older classes. (#5698)

Motivation:
Micrometer 1.13.0 updates its Prometheus dependency from 0.x to 1.x. In Prometheus 1.x, the package of `PrometheusMeterRegistry` has changed and `CollectorRegistry` is no longer used. More details can be found in the [migration guide](https://github.com/micrometer-metrics/micrometer/wiki/1.13-Migration-Guide).

Modifications:
- Updated Micrometer from 1.12.4 to 1.13.0.
- Removed the Micrometer 1.3 integration test module.
  - We dropped supporting Micrometer <= 1.5 already: #5661
- Updated Prometheus from 0.16.0 to 1.3.0.
- Added `armeria-prometheus1` module.
  -  `PrometheusMeterRegistries`, `PrometheusVersion1ExpositionService`, and its builder classes are added.
- Deprecated `PrometheusMeterRegistries`, `PrometheusExpositionService`, and its builder classes.

Result:
- The older `PrometheusMeterRegistries`, `PrometheusExpositionService`, and its builders are deprecated.
  - Use the same classes in the `armeria-prometheus1`.

Author: minwoox

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;