refact: EventerType and improve consistency

1. Completed the EventerType comment.
2. Changed EventerType to be represented as a string.
3. Since EventerType is designed to be entirely lowercase, changed the comparison to use lowercase instead of uppercase.
4. Renamed newEventJournalD to newJournalDEventer.
5. Removed redundant error-checking steps in events_linux.go.

Signed-off-by: ksw2000 <[email protected]>

libpod/events/config.go

@@ -6,16 +6,17 @@ import (
 	"time"
 )
 
-// EventerType ...
-type EventerType int
+// EventerType describes the type of event logger
+// The string values for EventerType should be entirely lowercase.
+type EventerType string
 
 const (
 	// LogFile indicates the event logger will be a logfile
-	LogFile EventerType = iota
+	LogFile EventerType = "file"
 	// Journald indicates journald should be used to log events
-	Journald EventerType = iota
+	Journald EventerType = "journald"
 	// Null is a no-op events logger. It does not read or write events.
-	Null EventerType = iota
+	Null EventerType = "none"
 )
 
 // Event describes the attributes of a libpod event

libpod/events/events.go

@@ -15,26 +15,13 @@ var ErrNoJournaldLogging = errors.New("no support for journald logging")
 
 // String returns a string representation of EventerType
 func (et EventerType) String() string {
-	switch et {
-	case LogFile:
-		return "file"
-	case Journald:
-		return "journald"
-	case Null:
-		return "none"
-	default:
-		return "invalid"
-	}
+	return string(et)
 }
 
 // IsValidEventer checks if the given string is a valid eventer type.
 func IsValidEventer(eventer string) bool {
-	switch eventer {
-	case LogFile.String():
-		return true
-	case Journald.String():
-		return true
-	case Null.String():
+	switch EventerType(eventer) {
+	case LogFile, Journald, Null:
 		return true
 	default:
 		return false

libpod/events/events_freebsd.go

@@ -10,12 +10,12 @@ import (
 // NewEventer creates an eventer based on the eventer type
 func NewEventer(options EventerOptions) (Eventer, error) {
 	logrus.Debugf("Initializing event backend %s", options.EventerType)
-	switch strings.ToUpper(options.EventerType) {
-	case strings.ToUpper(LogFile.String()):
+	switch EventerType(strings.ToLower(options.EventerType)) {
+	case LogFile:
 		return EventLogFile{options}, nil
-	case strings.ToUpper(Null.String()):
+	case Null:
 		return newNullEventer(), nil
 	default:
-		return nil, fmt.Errorf("unknown event logger type: %s", strings.ToUpper(options.EventerType))
+		return nil, fmt.Errorf("unknown event logger type: %s", strings.ToLower(options.EventerType))
 	}
 }

libpod/events/events_linux.go

@@ -10,18 +10,14 @@ import (
 // NewEventer creates an eventer based on the eventer type
 func NewEventer(options EventerOptions) (Eventer, error) {
 	logrus.Debugf("Initializing event backend %s", options.EventerType)
-	switch strings.ToUpper(options.EventerType) {
-	case strings.ToUpper(Journald.String()):
-		eventer, err := newEventJournalD(options)
-		if err != nil {
-			return nil, fmt.Errorf("eventer creation: %w", err)
-		}
-		return eventer, nil
-	case strings.ToUpper(LogFile.String()):
+	switch EventerType(strings.ToLower(options.EventerType)) {
+	case Journald:
+		return newJournalDEventer(options)
+	case LogFile:
 		return newLogFileEventer(options)
-	case strings.ToUpper(Null.String()):
+	case Null:
 		return newNullEventer(), nil
 	default:
-		return nil, fmt.Errorf("unknown event logger type: %s", strings.ToUpper(options.EventerType))
+		return nil, fmt.Errorf("unknown event logger type: %s", strings.ToLower(options.EventerType))
 	}
 }

libpod/events/journal_linux.go

@@ -25,8 +25,8 @@ type EventJournalD struct {
 	options EventerOptions
 }
 
-// newEventJournalD creates a new journald Eventer
-func newEventJournalD(options EventerOptions) (Eventer, error) {
+// newJournalDEventer creates a new EventJournalD Eventer
+func newJournalDEventer(options EventerOptions) (Eventer, error) {
 	return EventJournalD{options}, nil
 }
 

libpod/events/journal_unsupported.go

@@ -5,7 +5,7 @@ package events
 // DefaultEventerType is logfile when systemd is not present
 const DefaultEventerType = LogFile
 
-// newEventJournalD always returns an error if libsystemd not found
-func newEventJournalD(options EventerOptions) (Eventer, error) {
+// newJournalDEventer always returns an error if libsystemd not found
+func newJournalDEventer(options EventerOptions) (Eventer, error) {
 	return nil, ErrNoJournaldLogging
 }