package main
import (
_ "embed"
"flag"
"fmt"
"log"
"net"
"net/http"
"os"
"os/exec"
"sort"
"strings"
"time"
"tailscale.com/tsnet"
)
//go:embed generate_images.sh
var genScript []byte
//go:embed style.css
var style string
func main() {
tmpDir, err := os.MkdirTemp("", "tsvnstat")
if err != nil {
log.Fatal(err)
}
defer os.RemoveAll(tmpDir)
tmpFile, err := os.CreateTemp("", "generate_images.sh")
if err != nil {
log.Fatal(err)
}
defer os.Remove(tmpFile.Name())
if _, err := tmpFile.Write(genScript); err != nil {
log.Fatal(err)
}
if err := tmpFile.Close(); err != nil {
log.Fatal(err)
}
err = os.Chmod(tmpFile.Name(), 0700)
if err != nil {
log.Fatal(err)
}
name := flag.String("name", "", "name of service")
dir := flag.String("dir", tmpDir, "directory containing vnstat images")
key := flag.String("key", "", "path to file containing the api key")
shell := flag.String("sh", "/bin/sh", "path to interpreter")
flag.Parse()
s := &tsnet.Server{
Hostname: *name,
}
if *key != "" {
keyData, err := os.ReadFile(*key)
if err != nil {
log.Fatal(err)
}
s.AuthKey = string(keyData)
}
ln, err := s.Listen("tcp", ":80")
if err != nil {
log.Fatal(err)
}
defer ln.Close()
host, err := os.Hostname()
if err != nil {
log.Fatal(err)
}
go func() {
for {
log.Printf("running %q in %q", tmpFile.Name(), tmpDir)
ifaces, err := net.Interfaces()
if err != nil {
log.Fatal("can't get interfaces...", err)
}
cmd := []string{tmpFile.Name()}
for _, intf := range ifaces {
cmd = append(cmd, intf.Name)
}
genCmd := exec.Command(*shell, cmd...)
genCmd.Dir = *dir
out, err := genCmd.Output()
if err != nil {
log.Fatal("can't run generation script", err)
}
log.Println(string(out))
time.Sleep(5 * time.Minute)
}
}()
mux := http.NewServeMux()
fileServer := http.FileServer(http.Dir(*dir))
mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
fileServer.ServeHTTP(w, r)
})
mux.HandleFunc("/index.html", func(w http.ResponseWriter, r *http.Request) {
images, err := os.ReadDir(*dir)
if err != nil {
http.Error(w, err.Error(), 500)
return
}
fmt.Fprintf(w, `
%s
vnstat for %s
`, host, style, host)
sort.Slice(images, func(i, j int) bool {
return images[i].Name() < images[j].Name()
})
prefix := ""
oldPrefix := ""
for _, img := range images {
in := img.Name()
imgPrefix := strings.Split(in, "-")[0]
headImg := fmt.Sprintf("%s-s.png", imgPrefix)
if prefix != imgPrefix {
if oldPrefix != prefix {
fmt.Fprintf(w, "")
}
fmt.Fprintf(w, "
", headImg)
prefix = imgPrefix
}
if in != headImg {
fmt.Fprintf(w, "
", in)
}
}
})
hs := &http.Server{
Handler: mux,
}
log.Panic(hs.Serve(ln))
}