adds some simple counter and gauge metrics

Signed-off-by: Josh <[email protected]>

Author: j-mcfadden

go.mod

@@ -5,7 +5,7 @@ go 1.24.4
 toolchain go1.24.5
 
 require (
-	github.com/google/go-cmp v0.6.0
+	github.com/google/go-cmp v0.7.0
 	golang.org/x/net v0.40.0
 	modernc.org/sqlite v1.19.4
 	tailscale.com v1.86.2
@@ -29,6 +29,8 @@ require (
 	github.com/aws/aws-sdk-go-v2/service/ssooidc v1.28.13 // indirect
 	github.com/aws/aws-sdk-go-v2/service/sts v1.33.13 // indirect
 	github.com/aws/smithy-go v1.22.2 // indirect
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/coder/websocket v1.8.12 // indirect
 	github.com/coreos/go-iptables v0.7.1-0.20240112124308-65c67c9f46e6 // indirect
 	github.com/dblohm7/wingoes v0.0.0-20240119213807-a09d6be7affa // indirect
@@ -47,15 +49,20 @@ require (
 	github.com/jmespath/go-jmespath v0.4.0 // indirect
 	github.com/jsimonetti/rtnetlink v1.4.0 // indirect
 	github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51 // indirect
-	github.com/klauspost/compress v1.17.11 // indirect
+	github.com/klauspost/compress v1.18.0 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/mdlayher/genetlink v1.3.2 // indirect
 	github.com/mdlayher/netlink v1.7.3-0.20250113171957-fbb4dce95f42 // indirect
 	github.com/mdlayher/sdnotify v1.0.0 // indirect
 	github.com/mdlayher/socket v0.5.0 // indirect
 	github.com/miekg/dns v1.1.58 // indirect
 	github.com/mitchellh/go-ps v1.0.0 // indirect
+	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
 	github.com/prometheus-community/pro-bing v0.4.0 // indirect
+	github.com/prometheus/client_golang v1.23.0 // indirect
+	github.com/prometheus/client_model v0.6.2 // indirect
+	github.com/prometheus/common v0.65.0 // indirect
+	github.com/prometheus/procfs v0.16.1 // indirect
 	github.com/remyoudompheng/bigfft v0.0.0-20200410134404-eec4a21b6bb0 // indirect
 	github.com/safchain/ethtool v0.3.0 // indirect
 	github.com/tailscale/certstore v0.1.1-0.20231202035212-d3fa0460f47e // indirect
@@ -81,6 +88,7 @@ require (
 	golang.org/x/tools v0.33.0 // indirect
 	golang.zx2c4.com/wintun v0.0.0-20230126152724-0fa3db229ce2 // indirect
 	golang.zx2c4.com/wireguard/windows v0.5.3 // indirect
+	google.golang.org/protobuf v1.36.6 // indirect
 	gvisor.dev/gvisor v0.0.0-20250205023644-9414b50a5633 // indirect
 	lukechampine.com/uint128 v1.2.0 // indirect
 	modernc.org/cc/v3 v3.40.0 // indirect

go.sum

@@ -40,6 +40,10 @@ github.com/aws/aws-sdk-go-v2/service/sts v1.33.13 h1:3LXNnmtH3TURctC23hnC0p/39Q5
 github.com/aws/aws-sdk-go-v2/service/sts v1.33.13/go.mod h1:7Yn+p66q/jt38qMoVfNvjbm3D89mGBnkwDcijgtih8w=
 github.com/aws/smithy-go v1.22.2 h1:6D9hW43xKFrRx/tXXfAlIZc4JI+yQe6snnWcQyxSyLQ=
 github.com/aws/smithy-go v1.22.2/go.mod h1:irrKGvNn1InZwb2d7fkIRNucdfwR8R+Ts3wxYa/cJHg=
+github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
+github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
+github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
+github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/cilium/ebpf v0.15.0 h1:7NxJhNiBT3NG8pZJ3c+yfrVdHY8ScgKD27sScgjLMMk=
 github.com/cilium/ebpf v0.15.0/go.mod h1:DHp1WyrLeiBh19Cf/tfiSMhqheEiK8fXFZ4No0P1Hso=
 github.com/coder/websocket v1.8.12 h1:5bUXkEPPIbewrnkU8LTCLVaxi4N4J8ahufH2vlo4NAo=
@@ -83,6 +87,8 @@ github.com/google/btree v1.1.2 h1:xf4v41cLI2Z6FxbKm+8Bu+m8ifhj15JuZ9sa0jZCMUU=
 github.com/google/btree v1.1.2/go.mod h1:qOPhT0dTNdNzV6Z/lhRX0YXUafgPLFUh+gZMl761Gm4=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
+github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
 github.com/google/go-tpm v0.9.4 h1:awZRf9FwOeTunQmHoDYSHJps3ie6f1UlhS1fOdPEt1I=
 github.com/google/go-tpm v0.9.4/go.mod h1:h9jEsEECg7gtLis0upRBQU+GhYVH6jMjrFxI8u6bVUY=
 github.com/google/nftables v0.2.1-0.20240414091927-5e242ec57806 h1:wG8RYIyctLhdFk6Vl1yPGtSRtwGpVkWyZww1OCil2MI=
@@ -107,6 +113,8 @@ github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51 h1:Z9n2FFNU
 github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51/go.mod h1:CzGEWj7cYgsdH8dAjBGEr58BoE7ScuLd+fwFZ44+/x8=
 github.com/klauspost/compress v1.17.11 h1:In6xLpyWOi1+C7tXUUWv2ot1QvBjxevKAaI6IXrJmUc=
 github.com/klauspost/compress v1.17.11/go.mod h1:pMDklpSncoRMuLFrf1W9Ss9KT+0rH90U12bZKk7uwG0=
+github.com/klauspost/compress v1.18.0 h1:c/Cqfb0r+Yi+JtIEq73FWXVkRonBlf0CRNYc8Zttxdo=
+github.com/klauspost/compress v1.18.0/go.mod h1:2Pp+KzxcywXVXMr50+X0Q/Lsb43OQHYWRCY2AiWywWQ=
 github.com/kortschak/wol v0.0.0-20200729010619-da482cc4850a h1:+RR6SqnTkDLWyICxS1xpjCi/3dhyV+TgZwA6Ww3KncQ=
 github.com/kortschak/wol v0.0.0-20200729010619-da482cc4850a/go.mod h1:YTtCCM3ryyfiu4F7t8HQ1mxvp1UBdWM2r6Xa+nGWvDk=
 github.com/kr/fs v0.1.0 h1:Jskdu9ieNAYnjxsi0LbQp1ulIKZV1LAFgK1tWhpZgl8=
@@ -144,10 +152,18 @@ github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRI
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/prometheus-community/pro-bing v0.4.0 h1:YMbv+i08gQz97OZZBwLyvmmQEEzyfyrrjEaAchdy3R4=
 github.com/prometheus-community/pro-bing v0.4.0/go.mod h1:b7wRYZtCcPmt4Sz319BykUU241rWLe1VFXyiyWK/dH4=
+github.com/prometheus/client_golang v1.23.0 h1:ust4zpdl9r4trLY/gSjlm07PuiBq2ynaXXlptpfy8Uc=
+github.com/prometheus/client_golang v1.23.0/go.mod h1:i/o0R9ByOnHX0McrTMTyhYvKE4haaf2mW08I+jGAjEE=
 github.com/prometheus/client_model v0.6.1 h1:ZKSh/rekM+n3CeS952MLRAdFwIKqeY8b62p8ais2e9E=
 github.com/prometheus/client_model v0.6.1/go.mod h1:OrxVMOVHjw3lKMa8+x6HeMGkHMQyHDk9E3jmP2AmGiY=
+github.com/prometheus/client_model v0.6.2 h1:oBsgwpGs7iVziMvrGhE53c/GrLUsZdHnqNwqPLxwZyk=
+github.com/prometheus/client_model v0.6.2/go.mod h1:y3m2F6Gdpfy6Ut/GBsUqTWZqCUvMVzSfMLjcu6wAwpE=
 github.com/prometheus/common v0.55.0 h1:KEi6DK7lXW/m7Ig5i47x0vRzuBsHuvJdi5ee6Y3G1dc=
 github.com/prometheus/common v0.55.0/go.mod h1:2SECS4xJG1kd8XF9IcM1gMX6510RAEL65zxzNImwdc8=
+github.com/prometheus/common v0.65.0 h1:QDwzd+G1twt//Kwj/Ww6E9FQq1iVMmODnILtW1t2VzE=
+github.com/prometheus/common v0.65.0/go.mod h1:0gZns+BLRQ3V6NdaerOhMbwwRbNh9hkGINtQAsP5GS8=
+github.com/prometheus/procfs v0.16.1 h1:hZ15bTNuirocR6u0JZ6BAHHmwS1p8B4P6MRqxtzMyRg=
+github.com/prometheus/procfs v0.16.1/go.mod h1:teAbpZRB1iIAJYREa1LsoWUXykVXA1KlTmWl8x/U+Is=
 github.com/remyoudompheng/bigfft v0.0.0-20200410134404-eec4a21b6bb0 h1:OdAsTTz6OkFY5QxjkYwrChwuRruF69c169dPK26NUlk=
 github.com/remyoudompheng/bigfft v0.0.0-20200410134404-eec4a21b6bb0/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
 github.com/rogpeppe/go-internal v1.13.1 h1:KvO1DLK/DRN07sQ1LQKScxyZJuNnedQ5/wKSR38lUII=
@@ -228,6 +244,8 @@ golang.zx2c4.com/wireguard/windows v0.5.3 h1:On6j2Rpn3OEMXqBq00QEDC7bWSZrPIHKIus
 golang.zx2c4.com/wireguard/windows v0.5.3/go.mod h1:9TEe8TJmtwyQebdFwAkEWOPr3prrtqm+REGFifP60hI=
 google.golang.org/protobuf v1.35.1 h1:m3LfL6/Ca+fqnjnlqQXNpFPABW1UD7mjh8KO2mKFytA=
 google.golang.org/protobuf v1.35.1/go.mod h1:9fA7Ob0pmnwhb644+1+CVWFRbNajQ6iRojtC/QF5bRE=
+google.golang.org/protobuf v1.36.6 h1:z1NpPI8ku2WgiWnf+t9wTPsn6eP1L7ksHUlkfLvd9xY=
+google.golang.org/protobuf v1.36.6/go.mod h1:jduwjTPXsFjZGTmRluh+L6NjiWu7pchiJ2/5YcXBHnY=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=

golink.go

@@ -30,6 +30,8 @@ import (
 	texttemplate "text/template"
 	"time"
 
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"golang.org/x/net/xsrftoken"
 	"tailscale.com/client/tailscale"
 	"tailscale.com/hostinfo"
@@ -76,6 +78,35 @@ var stats struct {
 	dirty ClickStats
 }
 
+var (
+	clickCounter = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "golink_clicks_total",
+			Help: "Total number of clicks for a recognized GoLink",
+		},
+		[]string{"path"},
+	)
+)
+
+var (
+	clickNotFound = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "golink_not_found_total",
+			Help: "Total number of clicks for a GoLink doesn't exist",
+		},
+		[]string{"path"},
+	)
+)
+
+var (
+	totalLinkCount = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Name: "golinks_total",
+			Help: "Total number of GoLinks being served",
+		},
+	)
+)
+
 // LastSnapshot is the data snapshot (as returned by the /.export handler)
 // that will be loaded on startup.
 var LastSnapshot []byte
@@ -374,6 +405,7 @@ func flushStatsLoop() {
 
 // deleteLinkStats removes the link stats from memory.
 func deleteLinkStats(link *Link) {
+	totalLinkCount.Dec()
 	stats.mu.Lock()
 	delete(stats.clicks, link.Short)
 	delete(stats.dirty, link.Short)
@@ -416,6 +448,13 @@ func HSTS(h http.Handler) http.Handler {
 	})
 }
 
+// Initalize Prometheus Metrics
+func initMetrics() {
+	prometheus.MustRegister(clickCounter)
+	prometheus.MustRegister(totalLinkCount)
+	prometheus.MustRegister(clickNotFound)
+}
+
 // serverHandler returns the main http.Handler for serving all requests.
 func serveHandler() http.Handler {
 	mux := http.NewServeMux()
@@ -426,8 +465,11 @@ func serveHandler() http.Handler {
 	mux.HandleFunc("/.opensearch", serveOpenSearch)
 	mux.HandleFunc("/.all", serveAll)
 	mux.HandleFunc("/.delete/", serveDelete)
+	mux.Handle("/.metrics", promhttp.Handler())
 	mux.Handle("/.static/", http.StripPrefix("/.", http.FileServer(http.FS(embeddedFS))))
 
+	initMetrics()
+
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		// all internal URLs begin with a leading "."; any other URL is treated as a go link.
 		// Serve go links directly without passing through the ServeMux,
@@ -547,16 +589,20 @@ func serveGo(w http.ResponseWriter, r *http.Request) {
 	}
 
 	if errors.Is(err, fs.ErrNotExist) {
+		clickNotFound.WithLabelValues(short).Inc()
 		w.WriteHeader(http.StatusNotFound)
 		serveHome(w, r, short)
 		return
 	}
 	if err != nil {
+		clickNotFound.WithLabelValues(short).Inc()
 		log.Printf("serving %q: %v", short, err)
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
 
+	clickCounter.WithLabelValues(link.Short).Inc()
+
 	stats.mu.Lock()
 	if stats.clicks == nil {
 		stats.clicks = make(ClickStats)
@@ -940,6 +986,7 @@ func serveSave(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json")
 		json.NewEncoder(w).Encode(link)
 	}
+	totalLinkCount.Inc()
 }
 
 // canEditLink returns whether the specified user has permission to edit link.