Adding Upgrade to Enterprise version feature (#14539)

* Adding Upgrade to Enterprise version feature

* Addressing PR review comments, and adding some minor improvements

* Add tests file

* Addressing PR comments

* fix linter checks

* Storing and exposing the upgraded from TE info

* Fix showing errors on mac

* A more appropiate status code for not-supported upgrade

* Fixing tests

* Handling permissions errors

* More server logging around upgrade failures

* Apply text changes suggested from code review

Co-authored-by: Eric Sadur <57730300+esadur@users.noreply.github.com>

* Address PR review comments

* Only allow to restart the system after an upgrade

* Verify file signature before upgrade

* Adding limit to the downloaded file

* Simplifying the upgrade binary process with backup in memory

* Fixing backup/restore mechanism for the binary file

* Improve file permissions handling

* Askin the permissions for the right place (the parent directory)

* Fixing tests

* Addressing PR review comments

* Fix license headers

* Fixing retry layer

* Making it work on windows builds

* Adding license header

* Fixing 2 tests

* Fixing tests that need UpgradeFromTE System key mock

* Extracting i18n translation

* Apply suggestions from code review

Co-authored-by: Eric Sadur <57730300+esadur@users.noreply.github.com>

* Improving how the errors are written

* Fixing another error text

* Removing unneeded translation

* Fixing upgrade status strings

* Update i18n/en.json

Co-authored-by: Eric Sadur <57730300+esadur@users.noreply.github.com>

* Fixing tests

Co-authored-by: Eric Sadur <57730300+esadur@users.noreply.github.com>
Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

app/server.go

@@ -13,10 +13,12 @@ import (
 	"net/http"
 	"net/url"
 	"os"
+	"os/exec"
 	"path"
 	"strings"
 	"sync"
 	"sync/atomic"
+	"syscall"
 	"time"
 
 	"github.com/getsentry/sentry-go"
@@ -44,6 +46,7 @@ import (
 	"github.com/mattermost/mattermost-server/v5/services/searchengine/bleveengine"
 	"github.com/mattermost/mattermost-server/v5/services/timezones"
 	"github.com/mattermost/mattermost-server/v5/services/tracing"
+	"github.com/mattermost/mattermost-server/v5/services/upgrader"
 	"github.com/mattermost/mattermost-server/v5/store"
 	"github.com/mattermost/mattermost-server/v5/store/localcachelayer"
 	"github.com/mattermost/mattermost-server/v5/store/retrylayer"
@@ -723,6 +726,51 @@ func (s *Server) Shutdown() error {
 	return nil
 }
 
+func (s *Server) Restart() error {
+	percentage, err := s.UpgradeToE0Status()
+	if err != nil || percentage != 100 {
+		return errors.Wrap(err, "unable to restart because the system has not been upgraded")
+	}
+	s.Shutdown()
+
+	argv0, err := exec.LookPath(os.Args[0])
+	if err != nil {
+		return err
+	}
+
+	if _, err = os.Stat(argv0); err != nil {
+		return err
+	}
+
+	mlog.Info("Restarting server")
+	return syscall.Exec(argv0, os.Args, os.Environ())
+}
+
+func (s *Server) isUpgradedFromTE() bool {
+	val, err := s.Store.System().GetByName(model.SYSTEM_UPGRADED_FROM_TE_ID)
+	if err != nil {
+		return false
+	}
+	return val.Value == "true"
+}
+
+func (s *Server) CanIUpgradeToE0() error {
+	return upgrader.CanIUpgradeToE0()
+}
+
+func (s *Server) UpgradeToE0() error {
+	if err := upgrader.UpgradeToE0(); err != nil {
+		return err
+	}
+	upgradedFromTE := &model.System{Name: model.SYSTEM_UPGRADED_FROM_TE_ID, Value: "true"}
+	s.Store.System().Save(upgradedFromTE)
+	return nil
+}
+
+func (s *Server) UpgradeToE0Status() (int64, error) {
+	return upgrader.UpgradeToE0Status()
+}
+
 // Go creates a goroutine, but maintains a record of it to ensure that execution completes before
 // the server is shutdown.
 func (s *Server) Go(f func()) {