CHORE: Update Go, dependencies and add healthcheck endpoint

.github/workflows/go.yml

@@ -16,7 +16,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v6
       with:
-        go-version: 1.23
+        go-version: 1.24
 
     - name: Build
       run: go build -v ./...

Dockerfile

@@ -1,14 +1,14 @@
-FROM golang:1.22-alpine as builder
+FROM golang:1.24-alpine as builder
 
 RUN apk -U --no-cache add curl ca-certificates python3
 
 WORKDIR /app
 
 COPY . /app/
 
-RUN go test ./... && go build .
+RUN go build . && go test -v ./...
 
-FROM alpine:3.19 as final
+FROM alpine:3.22 as final
 
 COPY --from=builder /app/microproxy /usr/local/bin/
 

config.go

@@ -11,6 +11,8 @@ import (
 
 type Configuration struct {
 	Listen              string            `toml:"listen"`
+	HTTPListen          string            `toml:"http_listen"`
+	HealthCheckEnabled  string            `toml:"enable_health_check"`
 	AccessLog           string            `toml:"access_log"`
 	ActivityLog         string            `toml:"activity_log"`
 	AllowedConnectPorts []int             `toml:"allowed_connect_ports"`

config_test.go

@@ -19,6 +19,8 @@ func compareSlices(s1, s2 []int) bool {
 func TestConfigFile(t *testing.T) {
 	expected := Configuration{
 		Listen:              "127.0.0.1:3129",
+		HTTPListen:          "127.0.0.1:8080",
+		HealthCheckEnabled:  "on",
 		AccessLog:           "/tmp/microproxy.access.log",
 		AuthType:            "basic",
 		AuthRealm:           "proxy",
@@ -59,4 +61,12 @@ func TestConfigFile(t *testing.T) {
 	if conf.ForwardedForHeader != expected.ForwardedForHeader {
 		t.Errorf("Got %v, expected %v", conf.ForwardedForHeader, expected.ForwardedForHeader)
 	}
+
+	if conf.HTTPListen != expected.HTTPListen {
+		t.Errorf("Got %v, expected %v", conf.HTTPListen, expected.HTTPListen)
+	}
+
+	if conf.HealthCheckEnabled != expected.HealthCheckEnabled {
+		t.Errorf("Got %v, expected %v", conf.HealthCheckEnabled, expected.HealthCheckEnabled)
+	}
 }

docker-compose.yml

@@ -6,5 +6,8 @@ services:
       context: .
       dockerfile: Dockerfile
     image: microproxy:latest
+    command: [ "microproxy", "-config", "/usr/local/etc/microproxy.toml", "-i" ]
+    ports:
+      - "3128:3128"
     volumes:
       - ./microproxy-docker.toml:/usr/local/etc/microproxy.toml

go.mod

@@ -1,13 +1,13 @@
 module github.com/thekvs/microproxy
 
-go 1.23.0
+go 1.24.0
 
 require (
-	github.com/BurntSushi/toml v1.5.0
+	github.com/BurntSushi/toml v1.6.0
 	github.com/elazarl/goproxy v1.7.2
 )
 
 require (
-	golang.org/x/net v0.38.0 // indirect
-	golang.org/x/text v0.23.0 // indirect
+	golang.org/x/net v0.48.0 // indirect
+	golang.org/x/text v0.32.0 // indirect
 )

go.sum

@@ -1,5 +1,7 @@
 github.com/BurntSushi/toml v1.5.0 h1:W5quZX/G/csjUnuI8SUYlsHs9M38FC7znL0lIO+DvMg=
 github.com/BurntSushi/toml v1.5.0/go.mod h1:ukJfTF/6rtPPRCnwkur4qwRxa8vTRFBF0uk2lLoLwho=
+github.com/BurntSushi/toml v1.6.0 h1:dRaEfpa2VI55EwlIW72hMRHdWouJeRF7TPYhI+AUQjk=
+github.com/BurntSushi/toml v1.6.0/go.mod h1:ukJfTF/6rtPPRCnwkur4qwRxa8vTRFBF0uk2lLoLwho=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/elazarl/goproxy v1.7.2 h1:Y2o6urb7Eule09PjlhQRGNsqRfPmYI3KKQLFpCAV3+o=
@@ -10,7 +12,11 @@ github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOf
 github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 golang.org/x/net v0.38.0 h1:vRMAPTMaeGqVhG5QyLJHqNDwecKTomGeqbnfZyKlBI8=
 golang.org/x/net v0.38.0/go.mod h1:ivrbrMbzFq5J41QOQh0siUuly180yBYtLp+CKbEaFx8=
+golang.org/x/net v0.48.0 h1:zyQRTTrjc33Lhh0fBgT/H3oZq9WuvRR5gPC70xpDiQU=
+golang.org/x/net v0.48.0/go.mod h1:+ndRgGjkh8FGtu1w1FGbEC31if4VrNVMuKTgcAAnQRY=
 golang.org/x/text v0.23.0 h1:D71I7dUrlY+VX0gQShAThNGHFxZ13dGLBHQLVl1mJlY=
 golang.org/x/text v0.23.0/go.mod h1:/BLNzu4aZCJ1+kcD0DNRotWKage4q2rGVAg4o22unh4=
+golang.org/x/text v0.32.0 h1:ZD01bjUt1FQ9WJ0ClOL5vxgxOI/sVCNgX1YtKwcY0mU=
+golang.org/x/text v0.32.0/go.mod h1:o/rUWzghvpD5TXrTIBuJU77MTaN0ljMWE47kxGJQ7jY=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

microproxy.go

@@ -344,7 +344,7 @@ func setActivityLog(conf *Configuration, proxy *goproxy.ProxyHttpServer) {
 	}
 }
 
-func setSignalHandler(conf *Configuration, proxy *goproxy.ProxyHttpServer, logger *ProxyLogger) {
+func setSignalHandler(conf *Configuration, proxy *goproxy.ProxyHttpServer, logger *ProxyLogger, cancel context.CancelFunc) {
 	signalChannel := make(chan os.Signal, 1)
 	signal.Notify(signalChannel, os.Interrupt, syscall.SIGTERM, syscall.SIGUSR1)
 
@@ -357,6 +357,7 @@ func setSignalHandler(conf *Configuration, proxy *goproxy.ProxyHttpServer, logge
 				if err != nil {
 					log.Printf("Close error: %v", err)
 				}
+				cancel()
 				os.Exit(0)
 			case syscall.SIGUSR1:
 				proxy.Logger.Printf("got USR1 signal, reopening logs\n")
@@ -528,14 +529,55 @@ func setForwardProxy(conf *Configuration, proxy *goproxy.ProxyHttpServer) {
 	}
 }
 
-func startServer(addr string, handler http.Handler) error {
+func startProxyServer(addr string, handler http.Handler) error {
 	err := http.ListenAndServe(addr, handler)
 	if err != nil {
 		return fmt.Errorf("failed to start server: %w", err)
 	}
 	return nil
 }
 
+func startHTTPServer(addr string, health *ProxyHealth) error {
+	mux := http.NewServeMux()
+	mux.HandleFunc("/health", healthCheckHandler(health)) // Health check endpoint
+
+	server := &http.Server{
+		Addr:    addr,
+		Handler: mux,
+	}
+
+	err := server.ListenAndServe()
+	if err != nil {
+		return fmt.Errorf("failed to start server: %w", err)
+	}
+	return nil
+}
+
+func healthCheckHandler(health *ProxyHealth) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if health.IsHealthy() {
+			fmt.Fprintln(w, "Proxy is healthy")
+		} else {
+			http.Error(w, "Proxy is unhealthy", http.StatusServiceUnavailable)
+		}
+	}
+}
+
+func setupProxyHealthHandlers(conf *Configuration, proxy *goproxy.ProxyHttpServer, health *ProxyHealth) {
+	if conf.HealthCheckEnabled == "on" {
+		proxy.OnResponse().DoFunc(
+			func(resp *http.Response, ctx *goproxy.ProxyCtx) *http.Response {
+				proxy.Logger.Printf("Response code: %s", resp.StatusCode)
+				if resp.StatusCode == http.StatusProxyAuthRequired {
+					health.RecordFailure() // record a failure for auth errors
+				} else {
+					health.RecordSuccess() // record a success for valid responses
+				}
+				return resp
+			})
+	}
+}
+
 func main() {
 	configFile := flag.String("config", "microproxy.toml", "proxy configuration file")
 	proxyInsecure := flag.Bool("i", false, "allow insecure forward proxy connections")
@@ -551,19 +593,26 @@ func main() {
 		os.Exit(0)
 	}
 
+	// Create a context to handle termination signals
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
 	proxy := createProxy(conf)
 	proxy.Verbose = *verboseMode
 
 	logger := newProxyLogger(conf)
 
+	health := &ProxyHealth{Healthy: true, FailureLimit: 5}
+
 	setHTTPLoggingHandler(proxy, logger)
 	setForwardProxy(conf, proxy)
 	setAllowedConnectPortsHandler(conf, proxy)
 	setAllowedNetworksHandler(conf, proxy)
 	setForwardedForHeaderHandler(conf, proxy)
 	setViaHeaderHandler(conf, proxy)
 	setAddCustomHeadersHandler(conf, proxy)
-	setSignalHandler(conf, proxy, logger)
+	setupProxyHealthHandlers(conf, proxy, health)
+	setSignalHandler(conf, proxy, logger, cancel)
 
 	// To be called first while processing handlers' stack,
 	// has to be placed last in the source code.
@@ -574,8 +623,17 @@ func main() {
 	}
 
 	proxy.Logger.Printf("starting proxy\n")
-	proxy.Logger.Printf("listening on %v\n", conf.Listen)
-	proxy.Logger.Printf("using configuration file %v\n", *configFile)
 
-	log.Fatal(startServer(conf.Listen, proxy))
+	go func() {
+		log.Fatal(startProxyServer(conf.Listen, proxy))
+	}()
+
+	if conf.HealthCheckEnabled == "on" {
+		go func() {
+			log.Fatal(startHTTPServer(conf.HTTPListen, health))
+		}()
+	}
+
+	// Wait for the context to be closed
+	<-ctx.Done()
 }

microproxy.toml

@@ -1,4 +1,6 @@
 listen="127.0.0.1:3129"
+enable_health_check="on"
+http_listen="127.0.0.1:8080"
 access_log="/tmp/microproxy.access.log"
 activity_log="/tmp/microproxy.error.log"
 allowed_connect_ports=[443, 80]

proxyhealth.go

@@ -0,0 +1,32 @@
+package main
+
+import "sync"
+
+type ProxyHealth struct {
+	sync.Mutex
+	Healthy      bool
+	FailureCount int
+	FailureLimit int // Threshold of failures to consider the proxy as unhealthy
+}
+
+func (p *ProxyHealth) RecordFailure() {
+	p.Lock()
+	defer p.Unlock()
+	p.FailureCount++
+	if p.FailureCount >= p.FailureLimit {
+		p.Healthy = false
+	}
+}
+
+func (p *ProxyHealth) RecordSuccess() {
+	p.Lock()
+	defer p.Unlock()
+	p.Healthy = true
+	p.FailureCount = 0 // reset failure count on a successful request
+}
+
+func (p *ProxyHealth) IsHealthy() bool {
+	p.Lock()
+	defer p.Unlock()
+	return p.Healthy
+}