logger: add zap command line switches

Allow to tune preconfigured by --log-mode zap backend with standard
zap command line switches from controller-runtime (zap-devel,
zap-encoder, zap-log-level, zap-stacktrace-level,
zap-time-encoding)[1].

This brings flexibility in logger setup for development environments
first of all.

The patch does not change default logger setup and does not change
DSCI override functionality.

[1] https://sdk.operatorframework.io/docs/building-operators/golang/references/logging

Signed-off-by: Yauheni Kaliuta <[email protected]>

main.go

@@ -51,6 +51,7 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/client/config"
 	"sigs.k8s.io/controller-runtime/pkg/healthz"
 	logf "sigs.k8s.io/controller-runtime/pkg/log"
+	"sigs.k8s.io/controller-runtime/pkg/log/zap"
 	"sigs.k8s.io/controller-runtime/pkg/manager"
 	ctrlmetrics "sigs.k8s.io/controller-runtime/pkg/metrics/server"
 	ctrlwebhook "sigs.k8s.io/controller-runtime/pkg/webhook"
@@ -140,9 +141,12 @@ func main() { //nolint:funlen,maintidx
 	flag.StringVar(&operatorName, "operator-name", "opendatahub", "The name of the operator")
 	flag.StringVar(&logmode, "log-mode", "", "Log mode ('', prod, devel), default to ''")
 
+	opts := zap.Options{}
+	opts.BindFlags(flag.CommandLine)
+
 	flag.Parse()
 
-	ctrl.SetLogger(logger.NewLogger(logmode))
+	ctrl.SetLogger(logger.NewLoggerWithOptions(logmode, &opts))
 
 	// root context
 	ctx := ctrl.SetupSignalHandler()

pkg/logger/logger.go

@@ -1,6 +1,7 @@
 package logger
 
 import (
+	"flag"
 	"os"
 	"strings"
 
@@ -35,26 +36,40 @@ func LogWithLevel(logger logr.Logger, level string) logr.Logger {
 	return logger.V(verbosityLevel)
 }
 
+func NewLoggerWithOptions(mode string, override *zap.Options) logr.Logger {
+	opts := newOptions(mode)
+	overrideOptions(opts, override)
+	return newLogger(opts)
+}
+
 // in DSC component, to use different mode for logging, e.g. development, production
 // when not set mode it falls to "default" which is used by startup main.go.
 func NewLogger(mode string) logr.Logger {
+	return newLogger(newOptions(mode))
+}
+
+func newLogger(opts *zap.Options) logr.Logger {
+	return zap.New(zap.UseFlagOptions(opts))
+}
+
+func newOptions(mode string) *zap.Options {
 	var opts zap.Options
 	switch mode {
-	case "devel", "development": //  the most logging verbosity
+	case "devel", "development":
 		opts = zap.Options{
 			Development:     true,
 			StacktraceLevel: zapcore.WarnLevel,
 			Level:           zapcore.InfoLevel,
 			DestWriter:      os.Stdout,
 		}
-	case "prod", "production": // the least logging verbosity
+	case "prod", "production":
 		opts = zap.Options{
 			Development:     false,
 			StacktraceLevel: zapcore.ErrorLevel,
 			Level:           zapcore.InfoLevel,
 			DestWriter:      os.Stdout,
 			EncoderConfigOptions: []zap.EncoderConfigOption{func(config *zapcore.EncoderConfig) {
-				config.EncodeTime = zapcore.ISO8601TimeEncoder // human readable not epoch
+				config.EncodeTime = zapcore.ISO8601TimeEncoder
 				config.EncodeDuration = zapcore.SecondsDurationEncoder
 				config.LevelKey = "LogLevel"
 				config.NameKey = "Log"
@@ -72,5 +87,34 @@ func NewLogger(mode string) logr.Logger {
 			DestWriter:      os.Stdout,
 		}
 	}
-	return zap.New(zap.UseFlagOptions(&opts))
+	return &opts
+}
+
+func overrideOptions(orig, override *zap.Options) {
+	// Development is boolean, cannot check for nil, so check if it was set
+	isDevelopmentSet := false
+	flag.Visit(func(f *flag.Flag) {
+		if f.Name == "zap-devel" {
+			isDevelopmentSet = true
+		}
+	})
+	if isDevelopmentSet {
+		orig.Development = override.Development
+	}
+
+	if override.StacktraceLevel != nil {
+		orig.StacktraceLevel = override.StacktraceLevel
+	}
+
+	if override.Level != nil {
+		orig.Level = override.Level
+	}
+
+	if override.DestWriter != nil {
+		orig.DestWriter = override.DestWriter
+	}
+
+	if override.EncoderConfigOptions != nil {
+		orig.EncoderConfigOptions = append(orig.EncoderConfigOptions, override.EncoderConfigOptions...)
+	}
 }