logs: stream corrosion logs with 'uc machine logs corrosion' from container instead of journal (fixes #392)

internal/journal/journal.go

@@ -10,31 +10,11 @@ import (
 	"github.com/psviderski/uncloud/pkg/api"
 )
 
-const (
-	UnitUncloud   = "uncloud"
-	UnitDocker    = "docker"
-	UnitCorrosion = "uncloud-corrosion"
-)
-
-func ValidUnit(unit string) bool {
-	switch unit {
-	case UnitUncloud:
-	case UnitDocker:
-	case UnitCorrosion:
-	default:
-		return false
-	}
-	return true
-}
-
 const journalctl = "journalctl"
 
 var commandContext = exec.CommandContext // allow override for test
 
 func logs(ctx context.Context, unit string, opts api.ServiceLogsOptions) (io.ReadCloser, func() error, error) {
-	if !ValidUnit(unit) {
-		return nil, nil, fmt.Errorf("journal logs: invalid unit: %s", unit)
-	}
 	args := []string{"-u", unit, "--no-hostname"}
 	args = append(args, "-n")
 	if opts.Tail > -1 {