feat: initial

main.go

@@ -0,0 +1,62 @@
+package main
+
+import (
+	"embed"
+	"html"
+	"io/fs"
+	"log/slog"
+	"net/http"
+	"os"
+	"os/exec"
+	"strings"
+)
+
+//go:embed web/*
+var webFS embed.FS
+
+func main() {
+	addr := os.Getenv("LISTEN_ADDR")
+	if addr == "" {
+		addr = "127.0.0.1:8080"
+	}
+
+	static, err := fs.Sub(webFS, "web")
+	if err != nil {
+		slog.Error("embed fs", "err", err)
+		os.Exit(1)
+	}
+
+	indexHTML, err := fs.ReadFile(static, "index.html")
+	if err != nil {
+		slog.Error("read index", "err", err)
+		os.Exit(1)
+	}
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("GET /", func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/" {
+			http.NotFound(w, r)
+			return
+		}
+		uptime := uptimeLine()
+		body := strings.ReplaceAll(string(indexHTML), "{{uptime}}", html.EscapeString(uptime))
+		w.Header().Set("Content-Type", "text/html; charset=utf-8")
+		w.Header().Set("Cache-Control", "no-store")
+		_, _ = w.Write([]byte(body))
+	})
+	mux.Handle("GET /style.css", http.FileServer(http.FS(static)))
+
+	slog.Info("listening", "addr", addr)
+	if err := http.ListenAndServe(addr, mux); err != nil {
+		slog.Error("serve", "err", err)
+		os.Exit(1)
+	}
+}
+
+func uptimeLine() string {
+	out, err := exec.Command("uptime").Output()
+	if err != nil {
+		return "uptime unavailable"
+	}
+	return strings.TrimSpace(string(out))
+}