From 0029c06d3348f23aa9fc685d1cae404a4ada9387 Mon Sep 17 00:00:00 2001
From: Georgios Andrianakis <geoand@gmail.com>
Date: Mon, 21 Mar 2022 09:48:30 +0200
Subject: [PATCH] Activate request context when prometheus scraping is invoked

---
 .../export/handlers/PrometheusHandler.java    | 20 +++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/extensions/micrometer/runtime/src/main/java/io/quarkus/micrometer/runtime/export/handlers/PrometheusHandler.java b/extensions/micrometer/runtime/src/main/java/io/quarkus/micrometer/runtime/export/handlers/PrometheusHandler.java
index 1a3283734d26d..1b05851c58c37 100644
--- a/extensions/micrometer/runtime/src/main/java/io/quarkus/micrometer/runtime/export/handlers/PrometheusHandler.java
+++ b/extensions/micrometer/runtime/src/main/java/io/quarkus/micrometer/runtime/export/handlers/PrometheusHandler.java
@@ -8,6 +8,8 @@
 
 import io.micrometer.prometheus.PrometheusMeterRegistry;
 import io.prometheus.client.exporter.common.TextFormat;
+import io.quarkus.arc.Arc;
+import io.quarkus.arc.ManagedContext;
 import io.vertx.core.Handler;
 import io.vertx.core.buffer.Buffer;
 import io.vertx.core.http.HttpServerResponse;
@@ -31,11 +33,25 @@ public void handle(RoutingContext routingContext) {
             response.setStatusCode(500)
                     .setStatusMessage("Unable to resolve Prometheus registry instance");
         } else {
-            response.putHeader("Content-Type", TextFormat.CONTENT_TYPE_004)
-                    .end(Buffer.buffer(registry.scrape()));
+            ManagedContext requestContext = Arc.container().requestContext();
+            if (requestContext.isActive()) {
+                doHandle(response);
+            } else {
+                requestContext.activate();
+                try {
+                    doHandle(response);
+                } finally {
+                    requestContext.terminate();
+                }
+            }
         }
     }
 
+    private void doHandle(HttpServerResponse response) {
+        response.putHeader("Content-Type", TextFormat.CONTENT_TYPE_004)
+                .end(Buffer.buffer(registry.scrape()));
+    }
+
     private void setup() {
         Instance<PrometheusMeterRegistry> registries = CDI.current().select(PrometheusMeterRegistry.class,
                 Default.Literal.INSTANCE);