add / update the update commands

agent/update.go

@@ -0,0 +1,52 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strings"
+
+	"github.com/blang/semver"
+	"github.com/rhysd/go-github-selfupdate/selfupdate"
+)
+
+func updateBeszel() {
+	var latest *selfupdate.Release
+	var found bool
+	var err error
+	currentVersion := semver.MustParse(Version)
+	fmt.Println("beszel-agent", currentVersion)
+	fmt.Println("Checking for updates...")
+	latest, found, err = selfupdate.DetectLatest("henrygd/beszel")
+
+	if err != nil {
+		fmt.Println("Error checking for updates:", err)
+		os.Exit(1)
+	}
+
+	if !found {
+		fmt.Println("No updates found")
+		os.Exit(0)
+	}
+
+	fmt.Println("Latest version", "v", latest.Version)
+
+	if latest.Version.LTE(currentVersion) {
+		fmt.Println("You are up to date")
+		return
+	}
+
+	var binaryPath string
+	fmt.Printf("Updating from %s to %s...", currentVersion, latest.Version)
+	binaryPath, err = os.Executable()
+	if err != nil {
+		fmt.Println("Error getting binary path:", err)
+		os.Exit(1)
+	}
+	err = selfupdate.UpdateTo(latest.AssetURL, binaryPath)
+	if err != nil {
+		fmt.Println("Please try rerunning with sudo. Error:", err)
+		os.Exit(1)
+	}
+	log.Printf("Successfully updated: %s -> %s\n\n%s", currentVersion, latest.Version, strings.TrimSpace(latest.ReleaseNotes))
+}