component-base/logs: refactor registry

Moving the registry into its own package will avoid dependency cycles in future
PRs.

Creating loggers through a factory instead of storing pre-created instances
will make it possible to create the loggers differently depending on
configuration parameters.

The factory can also be used to provide additional meta data before creating
instances.

staging/src/k8s.io/component-base/logs/config.go

@@ -26,6 +26,7 @@ import (
 
 	cliflag "k8s.io/component-base/cli/flag"
 	"k8s.io/component-base/config"
+	"k8s.io/component-base/logs/registry"
 	"k8s.io/klog/v2"
 )
 
@@ -35,16 +36,13 @@ const (
 	JSONLogFormat    = "json"
 )
 
-// LogRegistry is new init LogFormatRegistry struct
-var LogRegistry = NewLogFormatRegistry()
-
 // loggingFlags captures the state of the logging flags, in particular their default value
 // before flag parsing. It is used by UnsupportedLoggingFlags.
 var loggingFlags pflag.FlagSet
 
 func init() {
 	// Text format is default klog format
-	LogRegistry.Register(DefaultLogFormat, nil)
+	registry.LogRegistry.Register(DefaultLogFormat, nil)
 
 	var fs flag.FlagSet
 	klog.InitFlags(&fs)
@@ -63,10 +61,10 @@ func BindLoggingFlags(c *config.LoggingConfiguration, fs *pflag.FlagSet) {
 	// hyphens, even if currently no normalization function is set for the
 	// flag set yet.
 	unsupportedFlags := strings.Join(unsupportedLoggingFlagNames(cliflag.WordSepNormalizeFunc), ", ")
-	formats := fmt.Sprintf(`"%s"`, strings.Join(LogRegistry.List(), `", "`))
+	formats := fmt.Sprintf(`"%s"`, strings.Join(registry.LogRegistry.List(), `", "`))
 	fs.StringVar(&c.Format, "logging-format", c.Format, fmt.Sprintf("Sets the log format. Permitted formats: %s.\nNon-default formats don't honor these flags: %s.\nNon-default choices are currently alpha and subject to change without warning.", formats, unsupportedFlags))
 	// No new log formats should be added after generation is of flag options
-	LogRegistry.Freeze()
+	registry.LogRegistry.Freeze()
 	fs.BoolVar(&c.Sanitization, "experimental-logging-sanitization", c.Sanitization, `[Experimental] When enabled prevents logging of fields tagged as sensitive (passwords, keys, tokens).
 Runtime log sanitization may introduce significant computation overhead and therefore should not be enabled in production.`)
 }

staging/src/k8s.io/component-base/logs/json/json.go

@@ -24,20 +24,15 @@ import (
 	"github.com/go-logr/zapr"
 	"go.uber.org/zap"
 	"go.uber.org/zap/zapcore"
+
+	"k8s.io/component-base/logs/registry"
 )
 
 var (
-	// JSONLogger is global json log format logr
-	JSONLogger logr.Logger
-
 	// timeNow stubbed out for testing
 	timeNow = time.Now
 )
 
-func init() {
-	JSONLogger = NewJSONLogger(zapcore.Lock(os.Stdout))
-}
-
 // NewJSONLogger creates a new json logr.Logger using the given Zap Logger to log.
 func NewJSONLogger(w zapcore.WriteSyncer) logr.Logger {
 	encoder := zapcore.NewJSONEncoder(encoderConfig)
@@ -63,3 +58,12 @@ func epochMillisTimeEncoder(_ time.Time, enc zapcore.PrimitiveArrayEncoder) {
 	millis := float64(nanos) / float64(time.Millisecond)
 	enc.AppendFloat64(millis)
 }
+
+// Factory produces JSON logger instances.
+type Factory struct{}
+
+func (f Factory) Create() logr.Logger {
+	return NewJSONLogger(zapcore.Lock(os.Stdout))
+}
+
+var _ registry.LogFormatFactory = Factory{}

staging/src/k8s.io/component-base/logs/json/register/register.go

@@ -19,9 +19,10 @@ package register
 import (
 	"k8s.io/component-base/logs"
 	json "k8s.io/component-base/logs/json"
+	"k8s.io/component-base/logs/registry"
 )
 
 func init() {
 	// JSON format is optional klog format
-	logs.LogRegistry.Register(logs.JSONLogFormat, &json.JSONLogger)
+	registry.LogRegistry.Register(logs.JSONLogFormat, json.Factory{})
 }

staging/src/k8s.io/component-base/logs/options.go

@@ -23,6 +23,7 @@ import (
 
 	"k8s.io/component-base/config"
 	"k8s.io/component-base/config/v1alpha1"
+	"k8s.io/component-base/logs/registry"
 	"k8s.io/component-base/logs/sanitization"
 )
 
@@ -58,11 +59,11 @@ func (o *Options) AddFlags(fs *pflag.FlagSet) {
 // Apply set klog logger from LogFormat type
 func (o *Options) Apply() {
 	// if log format not exists, use nil loggr
-	loggr, _ := LogRegistry.Get(o.Config.Format)
+	factory, _ := registry.LogRegistry.Get(o.Config.Format)
-	if loggr == nil {
+	if factory == nil {
 		klog.ClearLogger()
 	} else {
-		klog.SetLogger(*loggr)
+		klog.SetLogger(factory.Create())
 	}
 	if o.Config.Sanitization {
 		klog.SetLogFilter(&sanitization.SanitizingFilter{})

staging/src/k8s.io/component-base/logs/registry/registry.go

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package logs
+package registry
 
 import (
 	"fmt"
@@ -23,35 +23,45 @@ import (
 	"github.com/go-logr/logr"
 )
 
+// LogRegistry is new init LogFormatRegistry struct
+var LogRegistry = NewLogFormatRegistry()
+
 // LogFormatRegistry store klog format registry
 type LogFormatRegistry struct {
-	registry map[string]*logr.Logger
+	registry map[string]LogFormatFactory
 	frozen   bool
 }
 
+// LogFormatFactory provides support for a certain additional,
+// non-default log format.
+type LogFormatFactory interface {
+	// Create returns a logger.
+	Create() logr.Logger
+}
+
 // NewLogFormatRegistry return new init LogFormatRegistry struct
 func NewLogFormatRegistry() *LogFormatRegistry {
 	return &LogFormatRegistry{
-		registry: make(map[string]*logr.Logger),
+		registry: make(map[string]LogFormatFactory),
 		frozen:   false,
 	}
 }
 
 // Register new log format registry to global logRegistry.
 // nil is valid and selects the default klog output.
-func (lfr *LogFormatRegistry) Register(name string, logger *logr.Logger) error {
+func (lfr *LogFormatRegistry) Register(name string, factory LogFormatFactory) error {
 	if lfr.frozen {
 		return fmt.Errorf("log format is frozen, unable to register log format")
 	}
 	if _, ok := lfr.registry[name]; ok {
 		return fmt.Errorf("log format: %s already exists", name)
 	}
-	lfr.registry[name] = logger
+	lfr.registry[name] = factory
 	return nil
 }
 
 // Get specified log format logger
-func (lfr *LogFormatRegistry) Get(name string) (*logr.Logger, error) {
+func (lfr *LogFormatRegistry) Get(name string) (LogFormatFactory, error) {
 	re, ok := lfr.registry[name]
 	if !ok {
 		return nil, fmt.Errorf("log format: %s does not exists", name)
@@ -60,12 +70,12 @@ func (lfr *LogFormatRegistry) Get(name string) (*logr.Logger, error) {
 }
 
 // Set specified log format logger
-func (lfr *LogFormatRegistry) Set(name string, logger *logr.Logger) error {
+func (lfr *LogFormatRegistry) Set(name string, factory LogFormatFactory) error {
 	if lfr.frozen {
 		return fmt.Errorf("log format is frozen, unable to set log format")
 	}
 
-	lfr.registry[name] = logger
+	lfr.registry[name] = factory
 	return nil
 }
 

staging/src/k8s.io/component-base/logs/validate.go

@@ -22,6 +22,7 @@ import (
 	"k8s.io/apimachinery/pkg/util/validation/field"
 	cliflag "k8s.io/component-base/cli/flag"
 	"k8s.io/component-base/config"
+	"k8s.io/component-base/logs/registry"
 )
 
 func ValidateLoggingConfiguration(c *config.LoggingConfiguration, fldPath *field.Path) field.ErrorList {
@@ -36,7 +37,7 @@ func ValidateLoggingConfiguration(c *config.LoggingConfiguration, fldPath *field
 			}
 		}
 	}
-	if _, err := LogRegistry.Get(c.Format); err != nil {
+	if _, err := registry.LogRegistry.Get(c.Format); err != nil {
 		errs = append(errs, field.Invalid(fldPath.Child("format"), c.Format, "Unsupported log format"))
 	}
 	return errs

vendor/modules.txt

@@ -1952,6 +1952,7 @@ k8s.io/component-base/logs/datapol
 k8s.io/component-base/logs/json
 k8s.io/component-base/logs/json/register
 k8s.io/component-base/logs/logreduction
+k8s.io/component-base/logs/registry
 k8s.io/component-base/logs/sanitization
 k8s.io/component-base/logs/testinit
 k8s.io/component-base/metrics