From 6a2091796c31203031c8b79593cd0a0cc7959763 Mon Sep 17 00:00:00 2001
From: Tim Brown <Tpbrown@gmail.com>
Date: Tue, 26 Feb 2019 12:06:57 -0800
Subject: [PATCH] Cache-Control on Prometheus endpoint

This change adds a `Cache-Control` header on the endpoint so that reverse proxies and load balancers in front of Jenkins do not cache metrics.
---
 .../java/org/jenkinsci/plugins/prometheus/MetricsRequest.java | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/main/java/org/jenkinsci/plugins/prometheus/MetricsRequest.java b/src/main/java/org/jenkinsci/plugins/prometheus/MetricsRequest.java
index dba89d37c..dec733d98 100644
--- a/src/main/java/org/jenkinsci/plugins/prometheus/MetricsRequest.java
+++ b/src/main/java/org/jenkinsci/plugins/prometheus/MetricsRequest.java
@@ -17,6 +17,8 @@ public static HttpResponse prometheusResponse(final CollectorRegistry collectorR
             public void generateResponse(StaplerRequest request, StaplerResponse response, Object node) throws IOException, ServletException {
                 response.setStatus(StaplerResponse.SC_OK);
                 response.setContentType(TextFormat.CONTENT_TYPE_004);
+                response.addHeader("Cache-Control","must-revalidate,no-cache,no-store");
+
 
                 StringWriter buffer = new StringWriter();
                 TextFormat.write004(buffer, collectorRegistry.metricFamilySamples());
@@ -25,4 +27,4 @@ public void generateResponse(StaplerRequest request, StaplerResponse response, O
             }
         };
     }
-}
\ No newline at end of file
+}