changes per @ethanfrey comments

log/logger.go

@@ -1,10 +1,9 @@
 package log
 
 import (
-	"fmt"
+	"io"
 
 	kitlog "github.com/go-kit/kit/log"
-	"github.com/go-kit/kit/log/level"
 )
 
 // Logger is what any Tendermint library should take.
@@ -12,38 +11,21 @@ type Logger interface {
 	Debug(msg string, keyvals ...interface{}) error
 	Info(msg string, keyvals ...interface{}) error
 	Error(msg string, keyvals ...interface{}) error
+
+	With(keyvals ...interface{}) Logger
+	WithLevel(lvl string) Logger
 }
 
-// With returns a new contextual logger with keyvals prepended to those passed
-// to calls to Info, Debug or Error.
-func With(logger Logger, keyvals ...interface{}) Logger {
-	switch logger.(type) {
-	case *tmLogger:
-		return &tmLogger{kitlog.With(logger.(*tmLogger).srcLogger, keyvals...)}
-	case *nopLogger:
-		return logger
-	default:
-		panic(fmt.Sprintf("Unexpected logger of type %T", logger))
-	}
-}
-
-// WithLevel returns a copy of the logger with a level set to lvl.
-func WithLevel(logger Logger, lvl string) Logger {
-	switch logger.(type) {
-	case *tmLogger:
-		switch lvl {
-		case "info":
-			return &tmLogger{level.NewFilter(logger.(*tmLogger).srcLogger, level.AllowInfo())}
-		case "debug":
-			return &tmLogger{level.NewFilter(logger.(*tmLogger).srcLogger, level.AllowDebug())}
-		case "error":
-			return &tmLogger{level.NewFilter(logger.(*tmLogger).srcLogger, level.AllowError())}
-		default:
-			panic(fmt.Sprintf("Unexpected level %v, expect either \"info\" or \"debug\" or \"error\"", lvl))
-		}
-	case *nopLogger:
-		return logger
-	default:
-		panic(fmt.Sprintf("Unexpected logger of type %T", logger))
-	}
+// NewSyncWriter returns a new writer that is safe for concurrent use by
+// multiple goroutines. Writes to the returned writer are passed on to w. If
+// another write is already in progress, the calling goroutine blocks until
+// the writer is available.
+//
+// If w implements the following interface, so does the returned writer.
+//
+//    interface {
+//        Fd() uintptr
+//    }
+func NewSyncWriter(w io.Writer) io.Writer {
+	return kitlog.NewSyncWriter(w)
 }