Goのpanic,recover周りについて

[awakia]

この記事が秀逸
https://blog.golang.org/defer-panic-and-recover
panic, recover, deferの挙動の詳細が書いてある。

後は別件で、goroutineの中でのpanicはhandle出来ない。もちろんそのgoroutine内でdeferしてrecoverすれば大丈夫

[awakia]

ginのRecoveryミドルウェアのコード。
panicを500エラーになるように変えている

// Recovery returns a middleware that recovers from any panics and writes a 500 if there was one.
func Recovery() HandlerFunc {
	return RecoveryWithWriter(DefaultErrorWriter)
}

// RecoveryWithWriter returns a middleware for a given writer that recovers from any panics and writes a 500 if there was one.
func RecoveryWithWriter(out io.Writer) HandlerFunc {
	var logger *log.Logger
	if out != nil {
		logger = log.New(out, "\n\n\x1b[31m", log.LstdFlags)
	}
	return func(c *Context) {
		defer func() {
			if err := recover(); err != nil {
				if logger != nil {
					stack := stack(3)
					httprequest, _ := httputil.DumpRequest(c.Request, false)
					logger.Printf("[Recovery] panic recovered:\n%s\n%s\n%s%s", string(httprequest), err, stack, reset)
				}
				c.AbortWithStatus(500)
			}
		}()
		c.Next()
	}
}