diff --git a/logger.go b/logger.go new file mode 100644 index 0000000..0115067 --- /dev/null +++ b/logger.go @@ -0,0 +1,77 @@ +package viper + +import ( + "fmt" + + jww "github.com/spf13/jwalterweatherman" +) + +// Logger is a unified interface for various logging use cases and practices, including: +// - leveled logging +// - structured logging +type Logger interface { + // Trace logs a Trace event. + // + // Even more fine-grained information than Debug events. + // Loggers not supporting this level should fall back to Debug. + Trace(msg string, keyvals ...interface{}) + + // Debug logs a Debug event. + // + // A verbose series of information events. + // They are useful when debugging the system. + Debug(msg string, keyvals ...interface{}) + + // Info logs an Info event. + // + // General information about what's happening inside the system. + Info(msg string, keyvals ...interface{}) + + // Warn logs a Warn(ing) event. + // + // Non-critical events that should be looked at. + Warn(msg string, keyvals ...interface{}) + + // Error logs an Error event. + // + // Critical events that require immediate attention. + // Loggers commonly provide Fatal and Panic levels above Error level, + // but exiting and panicing is out of scope for a logging library. + Error(msg string, keyvals ...interface{}) +} + +type jwwLogger struct{} + +func (jwwLogger) Trace(msg string, keyvals ...interface{}) { + jww.TRACE.Printf(jwwLogMessage(msg, keyvals...)) +} + +func (jwwLogger) Debug(msg string, keyvals ...interface{}) { + jww.DEBUG.Printf(jwwLogMessage(msg, keyvals...)) +} + +func (jwwLogger) Info(msg string, keyvals ...interface{}) { + jww.INFO.Printf(jwwLogMessage(msg, keyvals...)) +} + +func (jwwLogger) Warn(msg string, keyvals ...interface{}) { + jww.WARN.Printf(jwwLogMessage(msg, keyvals...)) +} + +func (jwwLogger) Error(msg string, keyvals ...interface{}) { + jww.ERROR.Printf(jwwLogMessage(msg, keyvals...)) +} + +func jwwLogMessage(msg string, keyvals ...interface{}) string { + out := msg + + if len(keyvals) > 0 && len(keyvals)%2 == 1 { + keyvals = append(keyvals, nil) + } + + for i := 0; i <= len(keyvals)-2; i += 2 { + out = fmt.Sprintf("%s %v=%v", out, keyvals[i], keyvals[i+1]) + } + + return out +}