From b8b7e6032e2ff772d05a746b81625b0196ea8882 Mon Sep 17 00:00:00 2001
From: Klaus <32713077+hirosumee@users.noreply.github.com>
Date: Wed, 21 Sep 2022 10:09:26 +0700
Subject: [PATCH] support url mapper

---
 .idea/.gitignore                      |  8 ++++++++
 .idea/fiber-prometheus-middleware.iml |  9 +++++++++
 .idea/modules.xml                     |  8 ++++++++
 .idea/vcs.xml                         |  6 ++++++
 prometheus.go                         | 21 +++++++++++++++++----
 5 files changed, 48 insertions(+), 4 deletions(-)
 create mode 100644 .idea/.gitignore
 create mode 100644 .idea/fiber-prometheus-middleware.iml
 create mode 100644 .idea/modules.xml
 create mode 100644 .idea/vcs.xml

diff --git a/.idea/.gitignore b/.idea/.gitignore
new file mode 100644
index 0000000..13566b8
--- /dev/null
+++ b/.idea/.gitignore
@@ -0,0 +1,8 @@
+# Default ignored files
+/shelf/
+/workspace.xml
+# Editor-based HTTP Client requests
+/httpRequests/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml
diff --git a/.idea/fiber-prometheus-middleware.iml b/.idea/fiber-prometheus-middleware.iml
new file mode 100644
index 0000000..5e764c4
--- /dev/null
+++ b/.idea/fiber-prometheus-middleware.iml
@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="WEB_MODULE" version="4">
+  <component name="Go" enabled="true" />
+  <component name="NewModuleRootManager">
+    <content url="file://$MODULE_DIR$" />
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>
\ No newline at end of file
diff --git a/.idea/modules.xml b/.idea/modules.xml
new file mode 100644
index 0000000..0e40ce8
--- /dev/null
+++ b/.idea/modules.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/.idea/fiber-prometheus-middleware.iml" filepath="$PROJECT_DIR$/.idea/fiber-prometheus-middleware.iml" />
+    </modules>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/vcs.xml b/.idea/vcs.xml
new file mode 100644
index 0000000..94a25f7
--- /dev/null
+++ b/.idea/vcs.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/prometheus.go b/prometheus.go
index c5dd540..3f58770 100644
--- a/prometheus.go
+++ b/prometheus.go
@@ -1,13 +1,14 @@
 package fiberprom
 
 import (
+	"log"
+	"strconv"
+	"time"
+
 	"github.com/gofiber/adaptor/v2"
 	"github.com/gofiber/fiber/v2"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
-	"log"
-	"strconv"
-	"time"
 )
 
 var defaultMetricPath = "/metrics"
@@ -17,6 +18,8 @@ type Prometheus struct {
 	reqDur      *prometheus.HistogramVec
 	router      fiber.Router
 	MetricsPath string
+	// urlMapper is a map of url to be mapped to a different url to avoid too many labels
+	urlMapper map[string]string
 }
 
 // NewPrometheus generates a new set of metrics with a certain subsystem name
@@ -29,6 +32,10 @@ func NewPrometheus(subsystem string) *Prometheus {
 	return p
 }
 
+func (p *Prometheus) SetURLMapper(mapper map[string]string) {
+	p.urlMapper = mapper
+}
+
 func (p *Prometheus) registerMetrics(subsystem string) {
 	p.reqDur = prometheus.NewHistogramVec(
 		prometheus.HistogramOpts{
@@ -52,7 +59,7 @@ func (p *Prometheus) Use(r fiber.Router) {
 	r.Get(p.MetricsPath, prometheusHandler())
 }
 
-// HandlerFunc is onion or wraper to handler for fasthttp listenandserve
+// HandlerFunc is onion or wrapper to handler for fasthttp listenandserve
 func (p *Prometheus) HandlerFunc() fiber.Handler {
 	return func(ctx *fiber.Ctx) error {
 		uri := string(ctx.Request().URI().Path())
@@ -61,6 +68,12 @@ func (p *Prometheus) HandlerFunc() fiber.Handler {
 			return ctx.Next()
 		}
 
+		if len(p.urlMapper) > 0 {
+			if mappedPath, ok := p.urlMapper[uri]; ok {
+				uri = mappedPath
+			}
+		}
+
 		start := time.Now()
 
 		defer func() {