Error handling interfere with other Error handling middleware

[philipjoh]

Hello!

In my project we have our own global error handler that produce a custom http response, but we noticed that the output in the http response was printed 2 times because of this call:

slog-echo/middleware.go

Line 130 in 1205207

c.Error(err)

Reading the doc of the Error function says:

A side-effect of calling global error handler is that now Response has been committed (sent to the client) and middlewares up in chain can not change Response status code or Response body anymore.

Avoid using this method in handlers as no middleware will be able to effectively handle errors after that.

So would it make sense to just remove this call from this middleware? And perhaps instead just return the err in the end of this function? As the purpose of this library isn't to handle the error, just to log it?

[mgnsk]

I have a similar question.

When I use the Recover middleware and this middleware together, the log output is different depending on the order of middlewares:

When Recover middleware is before slogecho, slogecho never logs the panic, only Recover does.

e := echo.New()
e.Use(
  middleware.Recover(),
  slogecho.New(),
)

When slogecho is before Recover, both Recover logs the panic (with stacktrace) and slogecho logs the panic (without stacktrace).
vs

e := echo.New()
e.Use(
  slogecho.New(),
  middleware.Recover(),
)

I currently prefer the second option where both log. Recover logs the stacktrace and slogecho just the request.

Maybe one of the possible solutions would be to make slogecho handle panics so that the Recover middleware could be dropped.