tailscale/util/codegen/codegen.go
Josh Bleecher Snyder fb66ff7c78 util/codegen: add package
This is a package for shared utilities used in doing codegen programs.
The inaugural API is for writing gofmt'd code to a file.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
2021-09-17 16:46:08 -07:00

41 lines
1.2 KiB
Go

// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package codegen contains shared utilities for generating code.
package codegen
import (
"fmt"
"go/format"
"os"
)
// WriteFormatted writes code to path.
// It runs gofmt on it before writing;
// if gofmt fails, it writes code unchanged.
// Errors can include I/O errors and gofmt errors.
//
// The advantage of always writing code to path,
// even if gofmt fails, is that it makes debugging easier.
// The code can be long, but you need it in order to debug.
// It is nicer to work with it in a file than a terminal.
// It is also easier to interpret gofmt errors
// with an editor providing file and line numbers.
func WriteFormatted(code []byte, path string) error {
out, fmterr := format.Source(code)
if fmterr != nil {
out = code
}
ioerr := os.WriteFile(path, out, 0644)
// Prefer I/O errors. They're usually easier to fix,
// and until they're fixed you can't do much else.
if ioerr != nil {
return ioerr
}
if fmterr != nil {
return fmt.Errorf("%s:%v", path, fmterr)
}
return nil
}