From b17ffab8da4c1317d3bc6b2ef838abc1c979e2c5 Mon Sep 17 00:00:00 2001
From: Will Hunt <willh@matrix.org>
Date: Fri, 15 Jan 2021 13:42:44 +0000
Subject: [PATCH] Fix empty values on the /metrics endpoint

---
 changelog.d/296.bugfix              | 1 +
 src/components/prometheusmetrics.ts | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)
 create mode 100644 changelog.d/296.bugfix

diff --git a/changelog.d/296.bugfix b/changelog.d/296.bugfix
new file mode 100644
index 00000000..6f3b9a65
--- /dev/null
+++ b/changelog.d/296.bugfix
@@ -0,0 +1 @@
+Fix a bug where /metrics would report empty values.
\ No newline at end of file
diff --git a/src/components/prometheusmetrics.ts b/src/components/prometheusmetrics.ts
index eb28bad9..04f28744 100644
--- a/src/components/prometheusmetrics.ts
+++ b/src/components/prometheusmetrics.ts
@@ -380,11 +380,11 @@ export class PrometheusMetrics {
             // TODO: Ideally these metrics would be on a different port.
             // For now, leave this unauthenticated.
             checkToken: false,
-            handler: (_req: Request, res: Response) => {
+            handler: async (_req: Request, res: Response) => {
                 this.refresh();
 
                 try {
-                    const exposition = this.register.metrics();
+                    const exposition = await this.register.metrics();
 
                     res.set("Content-Type", "text/plain");
                     res.send(exposition);