yyewolf/bar

package main

import (
    "context"
    "crypto/md5"
    "fmt"
    "io"
    "net/http"
    "os"
    "os/exec"
    "strings"

    "github.com/google/go-github/v56/github"
    "github.com/sirupsen/logrus"
)

func init() {
    // Get checksum of current version
    localVersion, err := os.ReadFile("current.md5")
    if err != nil {
        logrus.WithError(err).Error("failed to open current.md5")
    }

    client := github.NewClient(nil)

    client = client.WithAuthToken(config.GithubToken)

    // list all organizations for user "willnorris"
    release, _, err := client.Repositories.GetLatestRelease(context.Background(), "CETEN-OpenBar", "bar")
    if err != nil {
        logrus.WithError(err).Error("failed to get latest release")
        return
    }

    var md5 string
    var tarball string

    for _, asset := range release.Assets {
        name := asset.GetName()
        if !strings.HasPrefix(name, "nfc") {
            continue
        }
        if strings.HasSuffix(name, "linux-amd64.tar.gz.md5") {
            md5 = asset.GetBrowserDownloadURL()
            logrus.WithField("url", md5).Info("found md5")
        }
        if strings.HasSuffix(name, "linux-amd64.tar.gz") {
            tarball = asset.GetBrowserDownloadURL()
        }
    }

    // Download md5
    r, err := http.Get(md5)
    if err != nil {
        logrus.WithError(err).Error("failed to get checksum")
        return
    }

    if r.StatusCode != http.StatusOK {
        logrus.WithField("status", r.StatusCode).Error("failed to get checksum")
        return
    }

    d, err := io.ReadAll(r.Body)
    if err != nil {
        logrus.WithError(err).Error("failed to read checksum")
        return
    }

    localChecksum := string(localVersion)
    remoteChecksum := string(d)

    logrus.WithFields(logrus.Fields{
        "local":  localChecksum,
        "remote": remoteChecksum,
    }).Info("checksums")

    if localChecksum != remoteChecksum {
        performUpdate(remoteChecksum, tarball)
    }

    logrus.Info("checksum OK")
}

func performUpdate(checksum, tarball string) {
    logrus.Info("performing update")
    r, err := http.Get(tarball)
    if err != nil {
        logrus.WithError(err).Error("failed to get update")
        return
    }

    if r.StatusCode != http.StatusOK {
        logrus.WithField("status", r.StatusCode).Error("failed to get update")
        return
    }

    data, err := io.ReadAll(r.Body)
    if err != nil {
        logrus.WithError(err).Error("failed to read update")
        return
    }

    // verify checksum
    h := md5.New()
    _, err = h.Write(data)
    if err != nil {
        logrus.WithError(err).Error("failed to write update")
        return
    }

    if fmt.Sprintf("%x\n", h.Sum(nil)) != checksum {
        logrus.Error("checksum mismatch")
        return
    }

    // open a subprocess that will replace the current process file
    err = os.WriteFile("update.tar.gz", data, 0755)
    if err != nil {
        logrus.WithError(err).Error("failed to open process file")
        return
    }

    // write sh file that will finish the update
    err = os.WriteFile("update.sh", []byte(fmt.Sprintf(`#!/bin/sh
sleep 1s
rm nfc
tar -xzf update.tar.gz
chmod +x %s
rm update.tar.gz
rm LICENSE
rm update.sh
`, os.Args[0])), 0755)
    if err != nil {
        logrus.WithError(err).Error("failed to open process file")
        return
    }

    // chmod the sh file
    err = os.Chmod("update.sh", 0755)
    if err != nil {
        logrus.WithError(err).Error("failed to chmod sh file")
        return
    }

    // run the sh file in another process
    exec.Command("sh", "update.sh").Start()

    // save the checksum in current.md5
    err = os.WriteFile("current.md5", []byte(checksum), 0755)
    if err != nil {
        logrus.WithError(err).Error("failed to open process file")
        return
    }

    logrus.Info("update OK")
    logrus.Info("restarting")
    os.Exit(0)
}