enhancement(5235): added abstractions for changesymlink and rollbackInstall in upgrader, updated error handling tests to use these abstractions

Author: Kaan Yalti

internal/pkg/agent/application/upgrade/upgrade.go

@@ -83,6 +83,8 @@ type copyActionStoreFunc func(log *logger.Logger, newHome string) error
 type copyRunDirectoryFunc func(log *logger.Logger, oldRunPath, newRunPath string) error
 type fileDirCopyFunc func(from, to string, opts ...copy.Options) error
 type markUpgradeFunc func(log *logger.Logger, dataDirPath string, agent, previousAgent agentInstall, action *fleetapi.ActionUpgrade, upgradeDetails *details.Details, desiredOutcome UpgradeOutcome) error
+type changeSymlinkFunc func(log *logger.Logger, topDirPath, symlinkPath, newTarget string) error
+type rollbackInstallFunc func(ctx context.Context, log *logger.Logger, topDirPath, versionedHome, oldVersionedHome string) error
 
 // Types used to abstract stdlib functions
 type mkdirAllFunc func(name string, perm fs.FileMode) error
@@ -107,6 +109,8 @@ type Upgrader struct {
 	copyActionStore      copyActionStoreFunc
 	copyRunDirectory     copyRunDirectoryFunc
 	markUpgrade          markUpgradeFunc
+	changeSymlink        changeSymlinkFunc
+	rollbackInstall      rollbackInstallFunc
 }
 
 // IsUpgradeable when agent is installed and running as a service or flag was provided.
@@ -132,6 +136,8 @@ func NewUpgrader(log *logger.Logger, settings *artifact.Config, agentInfo info.A
 		copyActionStore:      copyActionStoreProvider(os.ReadFile, os.WriteFile),
 		copyRunDirectory:     copyRunDirectoryProvider(os.MkdirAll, copy.Copy),
 		markUpgrade:          markUpgradeProvider(UpdateActiveCommit, os.WriteFile),
+		changeSymlink:        changeSymlink,
+		rollbackInstall:      rollbackInstall,
 	}, nil
 }
 
@@ -365,9 +371,9 @@ func (u *Upgrader) Upgrade(ctx context.Context, version string, sourceURI string
 		return nil, fmt.Errorf("calculating home path relative to top, home: %q top: %q : %w", paths.Home(), paths.Top(), err)
 	}
 
-	if err := changeSymlink(u.log, paths.Top(), symlinkPath, newPath); err != nil {
+	if err := u.changeSymlink(u.log, paths.Top(), symlinkPath, newPath); err != nil {
 		u.log.Errorw("Rolling back: changing symlink failed", "error.message", err)
-		rollbackErr := rollbackInstall(ctx, u.log, paths.Top(), hashedDir, currentVersionedHome)
+		rollbackErr := u.rollbackInstall(ctx, u.log, paths.Top(), hashedDir, currentVersionedHome)
 		return nil, goerrors.Join(err, rollbackErr)
 	}
 
@@ -396,7 +402,7 @@ func (u *Upgrader) Upgrade(ctx context.Context, version string, sourceURI string
 		previous,     // old agent version data
 		action, det, OUTCOME_UPGRADE); err != nil {
 		u.log.Errorw("Rolling back: marking upgrade failed", "error.message", err)
-		rollbackErr := rollbackInstall(ctx, u.log, paths.Top(), hashedDir, currentVersionedHome)
+		rollbackErr := u.rollbackInstall(ctx, u.log, paths.Top(), hashedDir, currentVersionedHome)
 		return nil, goerrors.Join(err, rollbackErr)
 	}
 
@@ -405,14 +411,14 @@ func (u *Upgrader) Upgrade(ctx context.Context, version string, sourceURI string
 	var watcherCmd *exec.Cmd
 	if watcherCmd, err = InvokeWatcher(u.log, watcherExecutable); err != nil {
 		u.log.Errorw("Rolling back: starting watcher failed", "error.message", err)
-		rollbackErr := rollbackInstall(ctx, u.log, paths.Top(), hashedDir, currentVersionedHome)
+		rollbackErr := u.rollbackInstall(ctx, u.log, paths.Top(), hashedDir, currentVersionedHome)
 		return nil, goerrors.Join(err, rollbackErr)
 	}
 
 	watcherWaitErr := waitForWatcher(ctx, u.log, markerFilePath(paths.Data()), watcherMaxWaitTime)
 	if watcherWaitErr != nil {
 		killWatcherErr := watcherCmd.Process.Kill()
-		rollbackErr := rollbackInstall(ctx, u.log, paths.Top(), hashedDir, currentVersionedHome)
+		rollbackErr := u.rollbackInstall(ctx, u.log, paths.Top(), hashedDir, currentVersionedHome)
 		return nil, goerrors.Join(watcherWaitErr, killWatcherErr, rollbackErr)
 	}
 

internal/pkg/agent/application/upgrade/upgrade_test.go

@@ -1472,6 +1472,12 @@ func TestUpgradeErrorHandling(t *testing.T) {
 				upgrader.copyRunDirectory = func(log *logger.Logger, oldRunPath, newRunPath string) error {
 					return nil
 				}
+				upgrader.changeSymlink = func(log *logger.Logger, topDirPath, symlinkPath, newTarget string) error {
+					return nil
+				}
+				upgrader.rollbackInstall = func(ctx context.Context, log *logger.Logger, topDirPath, versionedHome, oldVersionedHome string) error {
+					return nil
+				}
 				upgrader.markUpgrade = func(log *logger.Logger, dataDirPath string, agent, previousAgent agentInstall, action *fleetapi.ActionUpgrade, upgradeDetails *details.Details, desiredOutcome UpgradeOutcome) error {
 					return testError
 				}