logging/zap/ctxzap: add caller skip to shorthand functions (#429)

The caller annotations made by the shorthand logging functions are
`ctxzap/context.go:xx` regardless of where the shorthands are called.

This commit adds caller skip so that each log message has the correct
caller annotation.

logging/zap/ctxzap/context.go

@@ -66,23 +66,23 @@ func ToContext(ctx context.Context, logger *zap.Logger) context.Context {
 // Debug is equivalent to calling Debug on the zap.Logger in the context.
 // It is a no-op if the context does not contain a zap.Logger.
 func Debug(ctx context.Context, msg string, fields ...zap.Field) {
-	Extract(ctx).Debug(msg, fields...)
+	Extract(ctx).WithOptions(zap.AddCallerSkip(1)).Debug(msg, fields...)
 }
 
 // Info is equivalent to calling Info on the zap.Logger in the context.
 // It is a no-op if the context does not contain a zap.Logger.
 func Info(ctx context.Context, msg string, fields ...zap.Field) {
-	Extract(ctx).Info(msg, fields...)
+	Extract(ctx).WithOptions(zap.AddCallerSkip(1)).Info(msg, fields...)
 }
 
 // Warn is equivalent to calling Warn on the zap.Logger in the context.
 // It is a no-op if the context does not contain a zap.Logger.
 func Warn(ctx context.Context, msg string, fields ...zap.Field) {
-	Extract(ctx).Warn(msg, fields...)
+	Extract(ctx).WithOptions(zap.AddCallerSkip(1)).Warn(msg, fields...)
 }
 
 // Error is equivalent to calling Error on the zap.Logger in the context.
 // It is a no-op if the context does not contain a zap.Logger.
 func Error(ctx context.Context, msg string, fields ...zap.Field) {
-	Extract(ctx).Error(msg, fields...)
+	Extract(ctx).WithOptions(zap.AddCallerSkip(1)).Error(msg, fields...)
 }

logging/zap/ctxzap/context_test.go

@@ -2,6 +2,7 @@ package ctxzap
 
 import (
 	"context"
+	"runtime"
 	"testing"
 
 	"go.uber.org/zap"
@@ -31,8 +32,11 @@ func TestShorthands(t *testing.T) {
 				if e.Message != message {
 					t.Fatalf("message: expected %v, got %v", message, e.Message)
 				}
+				if _, file, _, _ := runtime.Caller(0); e.Caller.File != file {
+					t.Errorf("caller: expected %v, got %v", file, e.Caller.File)
+				}
 				return nil
-			})))
+			}))).WithOptions(zap.AddCaller())
 			ctx := ToContext(context.Background(), logger)
 			c.fn(ctx, message)
 			if !called {