replace klog with zap log.

[morvencao]

ref: https://issues.redhat.com/browse/ACM-17785

This PR replaces klog with zap logger. The log levels are:

• DebugLevel: Detailed debugging.
• InfoLevel: General info.
• WarnLevel: Warnings.
• ErrorLevel: Errors that don’t stop the program.
• DPanicLevel: Serious issues causing a panic when synced.
• PanicLevel: Immediate panic.
• FatalLevel: Critical errors that stop the app.

It also allows changing the log level at runtime via a ConfigMap in the maestro namespace:

# oc -n maestro get cm maestro-logging-config -o yaml
apiVersion: v1
data:
  config.yaml: |
    log_level: debug
kind: ConfigMap
metadata:
  name: maestro-logging-config
  namespace: maestro

This allows changing the log level without restarting the maestro pod.

[morvencao]

/assign @clyang82

[skeeey]

Please lower this log level, I missed this in last change :)

[morvencao]

done

[clyang82]

will the PathError handle the non-existed file path?

[morvencao]

yes, I did the test of no config file.

[clyang82]

remove redundant not

[morvencao]

done.

[clyang82]

Could we combine InitLogger and GetLogger into new GetLogger:

Suggested change

	func InitLogger(env string) {
	func GetLogger() *zap.SugaredLogger {
	if zapLogger == nil {
	zapLogLevel = zap.NewAtomicLevel()
	zapConfig := zap.NewDevelopmentConfig()
	zapConfig.DisableStacktrace = true
	zapConfig.Encoding = "console"
	if environments.GetEnvironmentStrFromEnv() == "development" {
	zapLogLevel.SetLevel(zapcore.DebugLevel)
	} else {
	zapLogLevel.SetLevel(zapcore.InfoLevel)
	}
	zapLogLevel.SetLevel(zapcore.InfoLevel)
	zapConfig.Level = zapLogLevel
	zlog, err := zapConfig.Build()
	if err != nil {
	panic(err)
	}
	zapLogger = zlog.Sugar()
	}
	return zapLogger
	}

[morvencao]

We can't merge InitLogger and zapLogger because InitLogger is called by the framework before the environment is initialized. GetLogger() is used in every package that needs to log messages. The zapLogger == nil check is necessary because, in unit tests, we don't use the framework, so it doesn't call InitLogger, in that case we initialize the logger in GetLogger().

[morvencao]

merged InitLogger() and GetLogger() as we discussed offline.

[clyang82]

/ok-to-test

[clyang82]

LGTM