feat: client config file listen event file change

client/client.go

@@ -38,6 +38,7 @@ func CheckAndDeployLocalCertificate(logger log.Logger, acmeClient *restclient.Cl
 		return
 	}
 
+	_ = level.Info(logger).Log("msg", "Checking local certificates with remote server")
 	certificates, err := acmeClient.GetAllCertificateMetadata()
 	if err != nil {
 		_ = level.Error(logger).Log("err", err)

client/watcher.go

@@ -1,24 +1,64 @@
 package client
 
 import (
+	"fmt"
+	"os"
+	"path/filepath"
 	"time"
 
+	"github.com/fsnotify/fsnotify"
 	"github.com/go-kit/log"
+	"github.com/go-kit/log/level"
 
 	"github.com/fgouteroux/acme_manager/restclient"
 )
 
-func WatchCertificate(logger log.Logger, interval time.Duration, configPath string, acmeClient *restclient.Client) {
+func WatchLocalCertificate(logger log.Logger, interval time.Duration, acmeClient *restclient.Client) {
 	// create a new Ticker
 	tk := time.NewTicker(interval)
 
 	// start the ticker
 	for range tk.C {
-
-		// Compare and create/update certificate from config file to remote server
-		CheckCertificate(logger, configPath, acmeClient)
-
 		// check local certificate are up-to-date
 		CheckAndDeployLocalCertificate(logger, acmeClient)
 	}
 }
+
+func WatchCertificateUpdate(logger log.Logger, configPath string, acmeClient *restclient.Client) {
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		_ = level.Error(logger).Log("err", err)
+		os.Exit(1)
+	}
+	defer watcher.Close()
+
+	fileName := filepath.Base(configPath)
+	if !filepath.IsAbs(configPath) {
+		fileName = "./" + fileName
+	}
+
+	// watch the parent dir of the file to catch changes
+	err = watcher.Add(filepath.Dir(configPath))
+	if err != nil {
+		_ = level.Error(logger).Log("err", err)
+		os.Exit(1)
+	}
+
+	for {
+		select {
+		case event := <-watcher.Events:
+			// only work on WRITE events of the original filename
+			if event.Op&fsnotify.Write == fsnotify.Write && event.Name == fileName {
+				_ = level.Info(logger).Log("msg", fmt.Sprintf("modified file: %s", configPath))
+
+				// Compare and create/update certificate from config file to remote server
+				CheckCertificate(logger, configPath, acmeClient)
+
+				// check local certificate are up-to-date
+				CheckAndDeployLocalCertificate(logger, acmeClient)
+			}
+		case err := <-watcher.Errors:
+			_ = level.Error(logger).Log("err", err)
+		}
+	}
+}

main.go

@@ -127,13 +127,17 @@ func main() {
 			_ = level.Error(logger).Log("err", err)
 			os.Exit(1)
 		}
-		// Compare and create/update certificate from config file to remote server
+		// On startup compare and create/update certificate from config file to remote server
 		client.CheckCertificate(logger, *clientConfigPath, acmeClient)
 
-		// check local certificate are up-to-date
+		// on startup check local certificate are up-to-date
 		client.CheckAndDeployLocalCertificate(logger, acmeClient)
 
-		go client.WatchCertificate(logger, *clientCheckConfigInterval, *clientConfigPath, acmeClient)
+		// periodically check local certificate are up-to-date
+		go client.WatchLocalCertificate(logger, *clientCheckConfigInterval, acmeClient)
+
+		// listen for config file event change
+		go client.WatchCertificateUpdate(logger, *clientConfigPath, acmeClient)
 
 		http.Handle("/metrics", promhttp.Handler())