feat: prometheus metrics

cmd/root.go

@@ -8,12 +8,18 @@ import (
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
 
+	// "github.com/gorilla/mux" // Import Gorilla Mux
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+
 	"goblin/config"
 	"goblin/internal/paste"
-	"goblin/internal/router"
+	// "goblin/internal/router"
 )
 
-var verbose bool
+var (
+	verbose       bool
+	enableMetrics bool
+)
 
 var rootCmd = &cobra.Command{
 	Use:   "goblin",
@@ -57,13 +63,16 @@ var rootCmd = &cobra.Command{
 		log.Infof("Private mode: %v", private)
 
 		// Create the router and start the server using the router package
-		r := router.NewRouter()
+		// r := router.NewRouter()
+
+		// Add a new route for Prometheus metrics
+		http.Handle("/metrics", promhttp.Handler()) // Use Prometheus handler
 
 		log.Info("Server started")
 
 		log.Infof("Listening on port %s\n", port)
 
-		err = http.ListenAndServe(":"+port, r)
+		err = http.ListenAndServe(":"+port, nil) // Use nil handler for default routing
 		if err != nil {
 			log.Errorf("Error starting server: %v\n", err)
 		}
@@ -87,8 +96,9 @@ func intializeFlags() {
 	rootCmd.PersistentFlags().String("templateDirectory", "", "Template directory path")
 	rootCmd.PersistentFlags().String("logDir", "", "Log file location")
 	rootCmd.PersistentFlags().String("pasteDir", "", "Paste storage location")
-	rootCmd.PersistentFlags().BoolVar(&verbose, "verbose", false, "Print config values")
+	rootCmd.PersistentFlags().BoolVar(&verbose, "verbose", false, "Print config values and enable verbose logging")
 	rootCmd.PersistentFlags().Int("expire", 24, "Paste expiration duration in hours")
+	rootCmd.PersistentFlags().BoolVar(&enableMetrics, "metrics", false, "Enable Prometheus metrics")
 
 	viper.BindPFlag("Port", rootCmd.PersistentFlags().Lookup("port"))
 	viper.BindPFlag("Private", rootCmd.PersistentFlags().Lookup("private"))

config/viper.go

@@ -26,7 +26,8 @@ func LoadConfig() (*AppConfig, error) {
 	viper.SetDefault("TemplateDir", "templates")
 	viper.SetDefault("LogDir", "logs")
 	viper.SetDefault("PasteDir", "pastes")
-	viper.SetDefault("Expire", 24) // Default expiration duration in hours
+	viper.SetDefault("Expire", 24) //  in hours
+	viper.SetDefault("Metrics", false)
 
 	// read the configuration file if it's present
 	// goblin can also be configured through command lines during runtime

go.mod

@@ -4,18 +4,26 @@ go 1.20
 
 require (
 	github.com/gorilla/mux v1.8.0
+	github.com/prometheus/client_golang v1.16.0
 	github.com/sirupsen/logrus v1.9.3
 	github.com/spf13/cobra v1.7.0
 	github.com/spf13/viper v1.16.0
 )
 
 require (
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/cespare/xxhash/v2 v2.2.0 // indirect
 	github.com/fsnotify/fsnotify v1.6.0 // indirect
+	github.com/golang/protobuf v1.5.3 // indirect
 	github.com/hashicorp/hcl v1.0.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/magiconair/properties v1.8.7 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.4 // indirect
 	github.com/mitchellh/mapstructure v1.5.0 // indirect
 	github.com/pelletier/go-toml/v2 v2.0.8 // indirect
+	github.com/prometheus/client_model v0.3.0 // indirect
+	github.com/prometheus/common v0.42.0 // indirect
+	github.com/prometheus/procfs v0.10.1 // indirect
 	github.com/spf13/afero v1.9.5 // indirect
 	github.com/spf13/cast v1.5.1 // indirect
 	github.com/spf13/jwalterweatherman v1.1.0 // indirect
@@ -24,6 +32,7 @@ require (
 	github.com/subosito/gotenv v1.4.2 // indirect
 	golang.org/x/sys v0.8.0 // indirect
 	golang.org/x/text v0.9.0 // indirect
+	google.golang.org/protobuf v1.30.0 // indirect
 	gopkg.in/ini.v1 v1.67.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -38,7 +38,11 @@ cloud.google.com/go/storage v1.14.0/go.mod h1:GrKmX003DSIwi9o29oFT7YDnHYwZoctc3f
 dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7gZCb22OMCxBHrMx7a5I7Hp++hsVxbQ4BYO7hU=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
+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/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
+github.com/cespare/xxhash/v2 v2.2.0 h1:DC2CZ1Ep5Y4k3ZQ899DldepgrayRUGE6BBZ/cd9Cj44=
+github.com/cespare/xxhash/v2 v2.2.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/chzyer/logex v1.1.10/go.mod h1:+Ywpsq7O8HXn0nuIou7OrIPyXbp3wmkHB+jjWRnGsAI=
 github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e/go.mod h1:nSuG5e5PlCu98SY8svDHJxuZscDgtXS6KTTbou5AhLI=
 github.com/chzyer/test v0.0.0-20180213035817-a1ea475d72b1/go.mod h1:Q3SI9o4m/ZMnBNeIyt5eFwwo7qiLfzFZmjNmxjkiQlU=
@@ -87,6 +91,9 @@ github.com/golang/protobuf v1.4.0/go.mod h1:jodUvKwWbYaEsadDk5Fwe5c77LiNKVO9IDvq
 github.com/golang/protobuf v1.4.1/go.mod h1:U8fpvMrcmy5pZrNK1lt4xCsGvpyWQ/VVv6QDs8UjoX8=
 github.com/golang/protobuf v1.4.2/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw735rRwI=
 github.com/golang/protobuf v1.4.3/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw735rRwI=
+github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
+github.com/golang/protobuf v1.5.3 h1:KhyjKVUg7Usr/dYsdSqoFveMYd5ko72D+zANwlG1mmg=
+github.com/golang/protobuf v1.5.3/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
 github.com/google/btree v0.0.0-20180813153112-4030bb1f1f0c/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
 github.com/google/btree v1.0.0/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
 github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
@@ -98,6 +105,7 @@ github.com/google/go-cmp v0.5.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/
 github.com/google/go-cmp v0.5.1/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.2/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
 github.com/google/martian v2.1.0+incompatible/go.mod h1:9I4somxYTbIHy5NJKHRl3wXiIaQGbYVAs8BPL6v8lEs=
 github.com/google/martian/v3 v3.0.0/go.mod h1:y5Zk1BBys9G+gd6Jrk0W3cC1+ELVxBWuIGO+w/tUAp0=
@@ -138,6 +146,8 @@ github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/magiconair/properties v1.8.7 h1:IeQXZAiQcpL9mgcAe1Nu6cX9LLw6ExEHKjN0VQdvPDY=
 github.com/magiconair/properties v1.8.7/go.mod h1:Dhd985XPs7jluiymwWYZ0G4Z61jb3vdS329zhj2hYo0=
+github.com/matttproud/golang_protobuf_extensions v1.0.4 h1:mmDVorXM7PCGKw94cs5zkfA9PSy5pEvNWRP0ET0TIVo=
+github.com/matttproud/golang_protobuf_extensions v1.0.4/go.mod h1:BSXmuO+STAnVfrANrmjBb36TMTDstsz7MSK+HVaYKv4=
 github.com/mitchellh/mapstructure v1.5.0 h1:jeMsZIYE/09sWLaz43PL7Gy6RuMjD2eJVyuac5Z2hdY=
 github.com/mitchellh/mapstructure v1.5.0/go.mod h1:bFUtVrKA4DC2yAKiSyO/QUcy7e+RRV2QTWOzhPopBRo=
 github.com/pelletier/go-toml/v2 v2.0.8 h1:0ctb6s9mE31h0/lhu+J6OPmVeDxJn+kYnJc2jZR9tGQ=
@@ -146,7 +156,15 @@ github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINE
 github.com/pkg/sftp v1.13.1/go.mod h1:3HaPG6Dq1ILlpPZRO0HVMrsydcdLt6HRDccSgb87qRg=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/prometheus/client_golang v1.16.0 h1:yk/hx9hDbrGHovbci4BY+pRMfSuuat626eFsHb7tmT8=
+github.com/prometheus/client_golang v1.16.0/go.mod h1:Zsulrv/L9oM40tJ7T815tM89lFEugiJ9HzIqaAx4LKc=
 github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
+github.com/prometheus/client_model v0.3.0 h1:UBgGFHqYdG/TPFD1B1ogZywDqEkwp3fBMvqdiQ7Xew4=
+github.com/prometheus/client_model v0.3.0/go.mod h1:LDGWKZIo7rky3hgvBe+caln+Dr3dPggB5dvjtD7w9+w=
+github.com/prometheus/common v0.42.0 h1:EKsfXEYo4JpWMHH5cg+KOUWeuJSov1Id8zGR8eeI1YM=
+github.com/prometheus/common v0.42.0/go.mod h1:xBwqVerjNdUDjgODMpudtOMwlOwf2SaTr1yjz4b7Zbc=
+github.com/prometheus/procfs v0.10.1 h1:kYK1Va/YMlutzCGazswoHKo//tZVlFpKYh+PymziUAg=
+github.com/prometheus/procfs v0.10.1/go.mod h1:nwNm2aOCAYw8uTR/9bWRREkZFxAUcWzPHWJq+XBB/FM=
 github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
 github.com/rogpeppe/go-internal v1.9.0 h1:73kH8U+JUqXU8lRuOHeVHaa/SZPifC7BkcraZVejAe8=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
@@ -471,9 +489,13 @@ google.golang.org/protobuf v1.23.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2
 google.golang.org/protobuf v1.23.1-0.20200526195155-81db48ad09cc/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=
 google.golang.org/protobuf v1.24.0/go.mod h1:r/3tXBNzIEhYS9I1OUVjXDlt8tc493IdKGjtUeSXeh4=
 google.golang.org/protobuf v1.25.0/go.mod h1:9JNX74DMeImyA3h4bdi1ymwjUzf21/xIlbajtzgsN7c=
+google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
+google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
+google.golang.org/protobuf v1.30.0 h1:kPPoIgf3TsEvrm0PFe15JQ+570QVxYzEvvHqChK+cng=
+google.golang.org/protobuf v1.30.0/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=
 gopkg.in/ini.v1 v1.67.0 h1:Dgnx+6+nfE+IfzjUEISNeydPJh9AXNNsWbGP9KzCsOA=
 gopkg.in/ini.v1 v1.67.0/go.mod h1:pNLf8WUiyNEtQjuu5G5vTm06TEv9tsIgeAvK8hOrP4k=

internal/metrics/metrics.go

@@ -0,0 +1,50 @@
+package metrics
+
+import (
+	"github.com/gorilla/mux"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+var (
+	pasteLengthHistogram = promauto.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Namespace: "goblin",
+			Subsystem: "paste",
+			Name:      "length",
+			Help:      "Length of pastes",
+			Buckets:   prometheus.ExponentialBuckets(1, 2, 10), // Example buckets
+		},
+		[]string{"status"}, // Labels for success/failure
+	)
+
+	pasteCreatedCounter = promauto.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "goblin",
+			Subsystem: "paste",
+			Name:      "created_total",
+			Help:      "Total number of pastes created",
+		},
+		[]string{"status"}, // Labels for success/failure
+	)
+)
+
+// ObservePasteLength records the length of pastes.
+func ObservePasteLength(status string, length float64) {
+	pasteLengthHistogram.WithLabelValues(status).Observe(length)
+}
+
+// IncrementPasteCreatedCounter increments the paste creation counter.
+func IncrementPasteCreatedCounter(status string) {
+	pasteCreatedCounter.WithLabelValues(status).Inc()
+}
+
+// InitPrometheus initializes Prometheus metrics and registers a handler for /metrics endpoint.
+func InitPrometheus(router *mux.Router) {
+	// Register Prometheus metrics collectors here
+	// For example, you can use promauto to define and register metrics
+
+	// Register Prometheus HTTP handler for /metrics endpoint with the Mux router
+	router.Handle("/metrics", promhttp.Handler())
+}

internal/paste/paste.go

@@ -8,9 +8,9 @@ import (
 	"net/http"
 	"os"
 	"path/filepath"
-	"strings"
 	"time"
 
+	"goblin/internal/metrics"
 	"goblin/internal/util"
 
 	"github.com/gorilla/mux"
@@ -62,6 +62,7 @@ func CreatePasteHandler(w http.ResponseWriter, r *http.Request) {
 	content, err := io.ReadAll(r.Body)
 	if err != nil {
 		http.Error(w, "Failed to read request body", http.StatusBadRequest)
+		metrics.IncrementPasteCreatedCounter("failure")
 		return
 	}
 
@@ -96,6 +97,7 @@ func CreatePasteHandler(w http.ResponseWriter, r *http.Request) {
 	if err := util.CreateDirectoryIfNotExists(pasteDir); err != nil {
 		logger.Errorf("Failed to create paste directory: %v", err)
 		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+		metrics.IncrementPasteCreatedCounter("failure")
 		return
 	}
 
@@ -105,6 +107,7 @@ func CreatePasteHandler(w http.ResponseWriter, r *http.Request) {
 	if err != nil {
 		logger.Errorf("Failed to create paste file: %v", err)
 		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+		metrics.IncrementPasteCreatedCounter("failure")
 		return
 	}
 	defer pasteFile.Close()
@@ -114,32 +117,38 @@ func CreatePasteHandler(w http.ResponseWriter, r *http.Request) {
 	if err != nil {
 		logger.Errorf("Failed to write paste content to file: %v", err)
 		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+		metrics.IncrementPasteCreatedCounter("failure")
 		return
 	}
 
-	// Determine the protocol based on the request's TLS connection
+	// Construct the complete paste URL including the protocol
-	protocol := "http"
+	var protocol string
 	if r.TLS != nil {
 		protocol = "https"
+	} else {
+		protocol = "http"
 	}
-
-	// Construct the complete paste URL with the protocol
 	pasteURL := fmt.Sprintf("%s://%s/%s", protocol, r.Host, pasteID)
 
-	// Remove any trailing '%' character from the pasteURL
-	if strings.HasSuffix(pasteURL, "%") {
-		pasteURL = pasteURL[:len(pasteURL)-1]
-	}
-
 	// Write the paste URL in the response
 	response := fmt.Sprintf("Paste available at %s", pasteURL)
 	w.Write([]byte(response))
+
+	// Record metrics
+	metrics.IncrementPasteCreatedCounter("success")
+	metrics.ObservePasteLength("success", float64(len(content)))
 }
 
 func GetPasteHandler(w http.ResponseWriter, r *http.Request) {
 	vars := mux.Vars(r)
 	pasteID := vars["id"]
 
+	// Exclude the "/metrics" path
+	if pasteID == "metrics" {
+		http.NotFound(w, r)
+		return
+	}
+
 	p, exists := pasteMap[pasteID]
 	if !exists {
 		http.Error(w, "Paste not found", http.StatusNotFound)

internal/router/router.go

@@ -9,7 +9,9 @@ import (
 
 func NewRouter() http.Handler {
 	r := mux.NewRouter()
+
 	r.HandleFunc("/", paste.CreatePasteHandler).Methods("POST")
 	r.HandleFunc("/{id}", paste.GetPasteHandler).Methods("GET")
+
 	return r
 }