add metrics endpoint and metrics for config reload

config.go

@@ -7,6 +7,7 @@ import (
 	"path"
 	"time"
 
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/utilitywarehouse/git-mirror/pkg/giturl"
 	"github.com/utilitywarehouse/git-mirror/pkg/mirror"
 	"gopkg.in/yaml.v3"
@@ -20,31 +21,31 @@ const (
 	defaultSSHKnownHostsPath = "/etc/git-secret/known_hosts"
 )
 
-var defaultRoot = path.Join(os.TempDir(), "git-mirror")
+var (
+	defaultRoot = path.Join(os.TempDir(), "git-mirror")
+
+	configSuccess = prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "git_mirror_config_last_reload_successful",
+		Help: "Whether the last configuration reload attempt was successful.",
+	})
+	configSuccessTime = prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "git_mirror_config_last_reload_success_timestamp_seconds",
+		Help: "Timestamp of the last successful configuration reload.",
+	})
+)
 
 // WatchConfig polls the config file every interval and reloads if modified
-func WatchConfig(ctx context.Context, path string, watchConfig bool, interval time.Duration, onChange func(*mirror.RepoPoolConfig)) {
+func WatchConfig(ctx context.Context, path string, watchConfig bool, interval time.Duration, onChange func(*mirror.RepoPoolConfig) bool) {
 	var lastModTime time.Time
+	var success bool
 
 	for {
-		fileInfo, err := os.Stat(path)
-		if err != nil {
-			logger.Error("Error checking config file", "err", err)
-			time.Sleep(interval) // retry after given interval
-			continue
-		}
-
-		modTime := fileInfo.ModTime()
-		if modTime.After(lastModTime) {
-			logger.Info("reloading config file...")
-			lastModTime = modTime
-
-			newConfig, err := parseConfigFile(path)
-			if err != nil {
-				logger.Error("failed to reload config", "err", err)
-			} else {
-				onChange(newConfig)
-			}
+		lastModTime, success = loadConfig(path, lastModTime, onChange)
+		if success {
+			configSuccess.Set(1)
+			configSuccessTime.SetToCurrentTime()
+		} else {
+			configSuccess.Set(0)
 		}
 
 		if !watchConfig {
@@ -60,33 +61,60 @@ func WatchConfig(ctx context.Context, path string, watchConfig bool, interval ti
 	}
 }
 
-func ensureConfig(repoPool *mirror.RepoPool, newConfig *mirror.RepoPoolConfig) {
+func loadConfig(path string, lastModTime time.Time, onChange func(*mirror.RepoPoolConfig) bool) (time.Time, bool) {
+	fileInfo, err := os.Stat(path)
+	if err != nil {
+		logger.Error("Error checking config file", "err", err)
+		return lastModTime, false
+	}
+
+	modTime := fileInfo.ModTime()
+	if modTime.Equal(lastModTime) {
+		return lastModTime, true
+	}
+
+	logger.Info("reloading config file...")
+
+	newConfig, err := parseConfigFile(path)
+	if err != nil {
+		logger.Error("failed to reload config", "err", err)
+		return lastModTime, false
+	}
+	return modTime, onChange(newConfig)
+}
+
+func ensureConfig(repoPool *mirror.RepoPool, newConfig *mirror.RepoPoolConfig) bool {
+	success := true
 
 	// add default values
 	applyGitDefaults(newConfig)
 
 	// validate and apply defaults to new config before compare
 	if err := newConfig.ValidateAndApplyDefaults(); err != nil {
 		logger.Error("failed to validate new config", "err", err)
-		return
+		return false
 	}
 
 	newRepos, removedRepos := diffRepositories(repoPool, newConfig)
 	for _, repo := range removedRepos {
 		if err := repoPool.RemoveRepository(repo); err != nil {
 			logger.Error("failed to remove repository", "remote", repo, "err", err)
+			success = false
 		}
 	}
 	for _, repo := range newRepos {
 		if err := repoPool.AddRepository(repo); err != nil {
 			logger.Error("failed to add new repository", "remote", repo.Remote, "err", err)
+			success = false
 		}
 	}
 
 	// find matched repos and check for worktree diffs
 	for _, newRepoConf := range newConfig.Repositories {
 		repo, err := repoPool.Repository(newRepoConf.Remote)
 		if err != nil {
+			logger.Error("unable to check worktree changes", "remote", newRepoConf.Remote, "err", err)
+			success = false
 			continue
 		}
 
@@ -96,14 +124,21 @@ func ensureConfig(repoPool *mirror.RepoPool, newConfig *mirror.RepoPoolConfig) {
 		for _, wt := range removedWTs {
 			if err := repoPool.RemoveWorktreeLink(newRepoConf.Remote, wt); err != nil {
 				logger.Error("failed to remove worktree", "remote", newRepoConf.Remote, "link", wt, "err", err)
+				success = false
 			}
 		}
 		for _, wt := range newWTs {
 			if err := repoPool.AddWorktreeLink(newRepoConf.Remote, wt); err != nil {
 				logger.Error("failed to add worktree", "remote", newRepoConf.Remote, "link", wt.Link, "err", err)
+				success = false
 			}
 		}
 	}
+
+	// start mirror Loop on newly added repos
+	repoPool.StartLoop()
+
+	return success
 }
 
 func applyGitDefaults(mirrorConf *mirror.RepoPoolConfig) {

go.mod

@@ -12,6 +12,7 @@ require (
 require (
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
+	github.com/klauspost/compress v1.17.11 // indirect
 	github.com/kr/text v0.2.0 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
 	github.com/petermattis/goid v0.0.0-20250303134427-723919f7f203 // indirect

go.sum

@@ -13,6 +13,8 @@ github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
 github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
+github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
+github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
 github.com/petermattis/goid v0.0.0-20240813172612-4fcff4a6cae7/go.mod h1:pxMtw7cyUw6B2bRH0ZBANSPg+AoSud1I1iyJHI69jH4=

main.go

@@ -2,16 +2,21 @@ package main
 
 import (
 	"context"
+	"errors"
 	"flag"
 	"fmt"
 	"log/slog"
+	"net/http"
+	"net/http/pprof"
 	"os"
 	"os/signal"
 	"strconv"
 	"strings"
 	"syscall"
 	"time"
 
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/utilitywarehouse/git-mirror/pkg/mirror"
 )
 
@@ -74,6 +79,7 @@ func main() {
 	flagLogLevel := flag.String("log-level", envString("LOG_LEVEL", "info"), "Log level")
 	flagConfig := flag.String("config", envString("GIT_MIRROR_CONFIG", "/etc/git-mirror/config.yaml"), "Absolute path to the config file")
 	flagWatchConfig := flag.Bool("watch-config", envBool("GIT_MIRROR_WATCH_CONFIG", true), "watch config for changes and reload when changes encountered")
+	flagHttpBind := flag.String("http-bind-address", envString("GIT_MIRROR_HTTP_BIND", ":8098"), "The address the web server binds to")
 
 	flag.Usage = usage
 	flag.Parse()
@@ -83,6 +89,26 @@ func main() {
 		loggerLevel.Set(v)
 	}
 
+	mirror.EnableMetrics("", prometheus.NewRegistry())
+	prometheus.MustRegister(configSuccess, configSuccessTime)
+
+	server := &http.Server{
+		Addr:              *flagHttpBind,
+		ReadTimeout:       5 * time.Second,
+		WriteTimeout:      10 * time.Second,
+		IdleTimeout:       5 * time.Second,
+		ReadHeaderTimeout: 1 * time.Second,
+	}
+
+	mux := http.NewServeMux()
+	mux.Handle("/metrics", promhttp.Handler())
+	mux.HandleFunc("/debug/pprof/", pprof.Index)
+	mux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
+	mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
+	mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
+	mux.HandleFunc("/debug/pprof/trace", pprof.Trace)
+	server.Handler = mux
+
 	// path to resolve git
 	gitENV := []string{fmt.Sprintf("PATH=%s", os.Getenv("PATH"))}
 
@@ -93,22 +119,29 @@ func main() {
 		os.Exit(1)
 	}
 
-	onConfigChange := func(config *mirror.RepoPoolConfig) {
-		ensureConfig(repoPool, config)
-		// start mirror Loop on newly added repos
-		repoPool.StartLoop()
+	onConfigChange := func(config *mirror.RepoPoolConfig) bool {
+		return ensureConfig(repoPool, config)
 	}
 
 	// Start watching the config file
 	go WatchConfig(ctx, *flagConfig, *flagWatchConfig, 10*time.Second, onConfigChange)
 
+	go func() {
+		if err := server.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
+			logger.Error("HTTP server terminated", "err", err)
+		}
+	}()
+
 	//listenForShutdown
 	stop := make(chan os.Signal, 2)
 	signal.Notify(stop, os.Interrupt, syscall.SIGTERM)
 
 	<-stop
 
 	logger.Info("shutting down...")
+	if err := server.Shutdown(ctx); err != nil {
+		logger.Error("failed to shutdown http server", "err", err)
+	}
 	cancel()
 
 	select {