Merge pull request #50083 from geoand/#50057

Allow compression of metrics

Author: brunobat

extensions/micrometer/deployment/src/test/java/io/quarkus/micrometer/deployment/export/PrometheusEnabledTest.java

@@ -1,5 +1,8 @@
 package io.quarkus.micrometer.deployment.export;
 
+import static io.restassured.RestAssured.*;
+import static org.hamcrest.Matchers.is;
+
 import java.util.Set;
 
 import jakarta.inject.Inject;
@@ -12,7 +15,6 @@
 import io.micrometer.core.instrument.composite.CompositeMeterRegistry;
 import io.micrometer.prometheus.PrometheusMeterRegistry;
 import io.quarkus.test.QuarkusUnitTest;
-import io.restassured.RestAssured;
 
 public class PrometheusEnabledTest {
     @RegisterExtension
@@ -23,6 +25,7 @@ public class PrometheusEnabledTest {
             .overrideConfigKey("quarkus.micrometer.export.prometheus.enabled", "true")
             .overrideConfigKey("quarkus.micrometer.registry-enabled-default", "false")
             .overrideConfigKey("quarkus.redis.devservices.enabled", "false")
+            .overrideConfigKey("quarkus.http.enable-compression", "true")
             .withEmptyApplication();
 
     @Inject
@@ -49,16 +52,22 @@ public void testMeterRegistryPresent() {
     @Test
     public void metricsEndpoint() {
         // RestAssured prepends /app for us
-        RestAssured.given()
+        given()
                 .accept("application/json")
                 .get("/q/metrics")
                 .then()
                 .log().all()
                 .statusCode(406);
 
-        RestAssured.given()
+        given()
                 .get("/q/metrics")
                 .then()
                 .statusCode(200);
+
+        given().header("Accept-Encoding", "gzip")
+                .get("/q/metrics")
+                .then()
+                .statusCode(200)
+                .header("content-encoding", is("gzip"));
     }
 }

extensions/micrometer/runtime/src/main/java/io/quarkus/micrometer/runtime/export/PrometheusRecorder.java

@@ -5,6 +5,7 @@
 import io.prometheus.client.exporter.common.TextFormat;
 import io.quarkus.micrometer.runtime.export.handlers.PrometheusHandler;
 import io.quarkus.runtime.annotations.Recorder;
+import io.quarkus.vertx.http.runtime.VertxHttpBuildTimeConfig;
 import io.vertx.core.Handler;
 import io.vertx.core.http.HttpHeaders;
 import io.vertx.ext.web.Route;
@@ -14,9 +15,16 @@
 public class PrometheusRecorder {
     PrometheusHandler handler;
 
-    public PrometheusHandler getHandler() {
+    private final VertxHttpBuildTimeConfig vertxHttpBuildTimeConfig;
+
+    public PrometheusRecorder(VertxHttpBuildTimeConfig vertxHttpBuildTimeConfig) {
+        this.vertxHttpBuildTimeConfig = vertxHttpBuildTimeConfig;
+    }
+
+    public Handler<RoutingContext> getHandler() {
         if (handler == null) {
-            handler = new PrometheusHandler();
+            handler = new PrometheusHandler(vertxHttpBuildTimeConfig.enableCompression(),
+                    vertxHttpBuildTimeConfig.compressMediaTypes());
         }
 
         return handler;

extensions/micrometer/runtime/src/main/java/io/quarkus/micrometer/runtime/export/handlers/PrometheusHandler.java

@@ -1,5 +1,10 @@
 package io.quarkus.micrometer.runtime.export.handlers;
 
+import java.util.Collections;
+import java.util.List;
+import java.util.Optional;
+import java.util.Set;
+
 import jakarta.enterprise.inject.Default;
 import jakarta.enterprise.inject.Instance;
 import jakarta.enterprise.inject.spi.CDI;
@@ -10,24 +15,55 @@
 import io.prometheus.client.exporter.common.TextFormat;
 import io.quarkus.arc.Arc;
 import io.quarkus.arc.ManagedContext;
+import io.quarkus.vertx.http.runtime.HttpCompressionHandler;
+import io.vertx.core.AsyncResult;
 import io.vertx.core.Handler;
 import io.vertx.core.buffer.Buffer;
 import io.vertx.core.http.HttpServerResponse;
 import io.vertx.ext.web.RoutingContext;
 
 public class PrometheusHandler implements Handler<RoutingContext> {
     private static final Logger log = Logger.getLogger(PrometheusHandler.class);
+    private final boolean enableCompression;
+    private final Set<String> compressMediaTypes;
 
     private PrometheusMeterRegistry registry;
 
     private boolean setup = false;
 
+    public PrometheusHandler(boolean enableCompression, Optional<List<String>> compressMediaTypes) {
+        this.enableCompression = enableCompression;
+        this.compressMediaTypes = determineCompressMediaTypes(compressMediaTypes);
+    }
+
+    private Set<String> determineCompressMediaTypes(Optional<List<String>> maybeCompressMediaTypes) {
+        if (maybeCompressMediaTypes.isPresent()) {
+            List<String> compressMediaTypes = maybeCompressMediaTypes.get();
+            if (compressMediaTypes.contains("text/plain")) {
+                return Set.of("text/plain", "application/openmetrics-text");
+            }
+        }
+        return Collections.emptySet();
+    }
+
     @Override
     public void handle(RoutingContext routingContext) {
         if (!setup) {
             setup();
         }
 
+        if (enableCompression) {
+            routingContext.addEndHandler(new Handler<>() {
+
+                @Override
+                public void handle(AsyncResult<Void> result) {
+                    if (result.succeeded()) {
+                        HttpCompressionHandler.compressIfNeeded(routingContext, compressMediaTypes);
+                    }
+                }
+            });
+        }
+
         HttpServerResponse response = routingContext.response();
         if (registry == null) {
             response.setStatusCode(500)