From 9e4603ed991f7705e9eb4dc75722e0f8a941e1aa Mon Sep 17 00:00:00 2001
From: Jim Lambert <jim_lambert@bose.com>
Date: Tue, 18 Sep 2018 10:02:33 -0400
Subject: [PATCH] support aggregate label for prometheus metrics

---
 middleware.go | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/middleware.go b/middleware.go
index c5a1924..4ededae 100644
--- a/middleware.go
+++ b/middleware.go
@@ -95,6 +95,9 @@ type Prometheus struct {
 	MetricsPath string
 
 	ReqCntURLLabelMappingFn RequestCounterURLLabelMappingFn
+
+	// gin.Context string to use as a prometheus URL label
+	URLLabelFromContext string
 }
 
 // PrometheusPushGateway contains the configuration for pushing to a Prometheus pushgateway (optional)
@@ -366,6 +369,14 @@ func (p *Prometheus) handlerFunc() gin.HandlerFunc {
 
 		p.reqDur.Observe(elapsed)
 		url := p.ReqCntURLLabelMappingFn(c)
+		// jlambert Oct 2018 - sidecar specific mod
+		if len(p.URLLabelFromContext) > 0 {
+			u, found := c.Get(p.URLLabelFromContext)
+			if !found {
+				u = "unknown"
+			}
+			url = u.(string)
+		}
 		p.reqCnt.WithLabelValues(status, c.Request.Method, c.HandlerName(), c.Request.Host, url).Inc()
 		p.reqSz.Observe(float64(reqSz))
 		p.resSz.Observe(resSz)