From 0b9286e993063c71d2e712e00ae14b7eb123c23f Mon Sep 17 00:00:00 2001
From: sanych-sun <alexes.polyakov@gmail.com>
Date: Tue, 20 Oct 2020 15:36:05 -0700
Subject: [PATCH] Try to resolve CollectorRegistryInstance before setup method
 call

---
 src/Prometheus.Client.AspNetCore/PrometheusExtensions.cs | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/Prometheus.Client.AspNetCore/PrometheusExtensions.cs b/src/Prometheus.Client.AspNetCore/PrometheusExtensions.cs
index ccbd6c7..da887d3 100644
--- a/src/Prometheus.Client.AspNetCore/PrometheusExtensions.cs
+++ b/src/Prometheus.Client.AspNetCore/PrometheusExtensions.cs
@@ -25,6 +25,9 @@ public static IApplicationBuilder UsePrometheusServer(this IApplicationBuilder a
         public static IApplicationBuilder UsePrometheusServer(this IApplicationBuilder app, Action<PrometheusOptions> setupOptions)
         {
             var options = new PrometheusOptions();
+            options.CollectorRegistryInstance
+                = (ICollectorRegistry)app.ApplicationServices.GetService(typeof(ICollectorRegistry)) ?? Metrics.DefaultCollectorRegistry;
+
             setupOptions?.Invoke(options);
 
             if (app == null)
@@ -36,10 +39,6 @@ public static IApplicationBuilder UsePrometheusServer(this IApplicationBuilder a
             if (!options.MapPath.StartsWith("/"))
                 throw new ArgumentException($"MapPath '{options.MapPath}' should start with '/'");
 
-            options.CollectorRegistryInstance
-                    ??= (ICollectorRegistry)app.ApplicationServices.GetService(typeof(ICollectorRegistry))
-                    ?? Metrics.DefaultCollectorRegistry;
-
             if (options.UseDefaultCollectors)
                 options.CollectorRegistryInstance.UseDefaultCollectors();