WIP auto updates

1 files changed, 178 insertions, 8 deletions

diff --git a/pkg/updates/updates.go b/pkg/updates/updates.go
index 77d491119..3599808fb 100644
--- a/pkg/updates/updates.go
+++ b/pkg/updates/updates.go
@@ -1,26 +1,196 @@
 package updates
 
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"os"
+	"path/filepath"
+	"runtime"
+
+	"github.com/kardianos/osext"
+
+	"github.com/Sirupsen/logrus"
+	getter "github.com/hashicorp/go-getter"
+	"github.com/jesseduffield/lazygit/pkg/commands"
+	"github.com/jesseduffield/lazygit/pkg/config"
+)
+
 // Update checks for updates and does updates
-type Update struct {
+type Updater struct {
 	LastChecked string
+	Log         *logrus.Logger
+	Config      config.AppConfigurer
+	NewVersion  string
+	OSCommand   *commands.OSCommand
 }
 
 // Updater implements the check and update methods
-type Updater interface {
-	Check()
+type Updaterer interface {
+	CheckForNewUpdate()
 	Update()
 }
 
+var (
+	projectUrl = "https://github.com/jesseduffield/lazygit"
+)
+
 // NewUpdater creates a new updater
-func NewUpdater() *Update {
+func NewUpdater(log *logrus.Logger, config config.AppConfigurer, osCommand *commands.OSCommand) (*Updater, error) {
 
-	update := &Update{
+	updater := &Updater{
 		LastChecked: "today",
+		Log:         log,
+		Config:      config,
+		OSCommand:   osCommand,
+	}
+	return updater, nil
+}
+
+func (u *Updater) getLatestVersionNumber() (string, error) {
+	req, err := http.NewRequest("GET", projectUrl+"/releases/latest", nil)
+	if err != nil {
+		return "", err
+	}
+	req.Header.Set("Accept", "application/json")
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return "", err
+	}
+
+	byt := []byte(body)
+	var dat map[string]interface{}
+	if err := json.Unmarshal(byt, &dat); err != nil {
+		return "", err
 	}
-	return update
+	return dat["tag_name"].(string), nil
 }
 
-// Check checks if there is an available update
-func (u *Update) Check() {
+// CheckForNewUpdate checks if there is an available update
+func (u *Updater) CheckForNewUpdate() (string, error) {
+	u.Log.Info("Checking for an updated version")
+	if u.Config.GetVersion() == "unversioned" {
+		u.Log.Info("Current version is not built from an official release so we won't check for an update")
+		return "", nil
+	}
+	newVersion, err := u.getLatestVersionNumber()
+	if err != nil {
+		return "", err
+	}
+	u.NewVersion = newVersion
+	u.Log.Info("Current version is " + u.Config.GetVersion())
+	u.Log.Info("New version is " + newVersion)
+	if newVersion == u.Config.GetVersion() {
+		return "", nil
+	}
+	// TODO: verify here that there is a binary available for this OS/arch
+	return newVersion, nil
+}
+
+func (u *Updater) mappedOs(os string) string {
+	osMap := map[string]string{
+		"darwin":  "Darwin",
+		"linux":   "Linux",
+		"windows": "Windows",
+	}
+	result, found := osMap[os]
+	if found {
+		return result
+	}
+	return os
+}
+
+func (u *Updater) mappedArch(arch string) string {
+	archMap := map[string]string{
+		"386":   "32-bit",
+		"amd64": "x86_64",
+	}
+	result, found := archMap[arch]
+	if found {
+		return result
+	}
+	return arch
+}
+
+// example: https://github.com/jesseduffield/lazygit/releases/download/v0.1.73/lazygit_0.1.73_Darwin_x86_64.tar.gz
+func (u *Updater) getBinaryUrl() (string, error) {
+	if u.NewVersion == "" {
+		return "", errors.New("Must run CheckForUpdate() before running getBinaryUrl() to get the new version number")
+	}
+	extension := "tar.gz"
+	if runtime.GOOS == "windows" {
+		extension = "zip"
+	}
+	url := fmt.Sprintf(
+		"%s/releases/download/%s/lazygit_%s_%s_%s.%s",
+		projectUrl,
+		u.NewVersion,
+		u.NewVersion[1:],
+		u.mappedOs(runtime.GOOS),
+		u.mappedArch(runtime.GOARCH),
+		extension,
+	)
+	u.Log.Info("url for latest release is " + url)
+	return url, nil
+}
+
+func (u *Updater) Update() error {
+	rawUrl, err := u.getBinaryUrl()
+	if err != nil {
+		return err
+	}
+	return u.downloadAndInstall(rawUrl)
+}
+
+func (u *Updater) downloadAndInstall(rawUrl string) error {
+	url, err := url.Parse(rawUrl)
+	if err != nil {
+		panic(err)
+	}
+
+	g := new(getter.HttpGetter)
+	tempDir, err := ioutil.TempDir("", "lazygit")
+	if err != nil {
+		panic(err)
+	}
+	defer os.RemoveAll(tempDir)
+
+	// Get it!
+	if err := g.Get(tempDir, url); err != nil {
+		panic(err)
+	}
+
+	extension := ""
+	if runtime.GOOS == "windows" {
+		extension = ".exe"
+	}
+
+	// Verify the main file exists
+	tempPath := filepath.Join(tempDir, "lazygit"+extension)
+	if _, err := os.Stat(tempPath); err != nil {
+		panic(err)
+	}
+
+	// get the path of the current binary
+	execPath, err := osext.Executable()
+	if err != nil {
+		panic(err)
+	}
+
+	// swap out the old binary for the new one
+	err = os.Rename(tempPath, execPath+"2")
+	if err != nil {
+		panic(err)
+	}
 
+	return nil
 }