Logging missed hits

[drekka]

So I've setup a number of responses in Hummingbird. Now I'm trying to log the times when a request comes in and no suitable response is found. How can I do that? I tried adding a logging middleware but it only seems to be called if there is a responder found.

[adam-fowler]

Can you post the code for your middleware and also the code for when you add it to your application

[drekka]

Currently I'm doing this:

struct RequestLogger: HBMiddleware {
    func apply(to request: HBRequest, next: HBResponder) -> EventLoopFuture<HBResponse> {
        os_log(.debug, log: .mocking, "👻 %@: Received request: %@ %@", String(describing: type(of: self)), String(describing: request.method), request.uri.path)
        return next.respond(to: request)
    }
}

// Then after starting the server
server.middleware.add(RequestLogger())

[drekka]

It's working when the server matches, but not when it doesn't.

[adam-fowler]

What other middleware do you have attached to the application? Have you set the logLevel of HBApplication.logger to display debug level logging eg HBApplication.logger.logLevel = .debug

[adam-fowler]

Also there is a route logger middleware already available in Hummingbird: HBLogRequestsMiddleware

[drekka]

That's the only middleware I'm using. Looking at using the debugging level. Originally added this middleware only to have the logging look the same as the rest of the code. So I'll take another look at HBLogRequestMiddleware as well.

[adam-fowler]

Here is a small example of a app where the logging gets called for every request regardless of whether there is a valid route. Replacing HBLogRequestsMiddleware should work fine here as well

@main
struct App {
    static func main() throws {
        let app = HBApplication()
        app.logger.logLevel = .debug
        app.middleware.add(HBLogRequestsMiddleware(.debug))
        app.router.get("/health") { _ -> HTTPResponseStatus in
            return .ok
        }
        try app.start()
        app.wait()
    }
}

[drekka]

OK, I think I've just worked this out. I was adding my middleware after starting the server, assuming that it didn't make any difference. But as I've just found out, if I do that then the responder chain inside the server is setup to call the trieRouter first before calling the middleware. If I add the middleware before starting the server then it is called before the trieRouter.

This appears to be related to the setup done in HBMiddlewareGroup.constructResponder(finalResponder:) function.

I had another look at the doco and it doesn't say anything about this (That I could find) so can I suggest adding to the middleware doco to outline that for it to be called before the router it must be added before starting the server.

[adam-fowler]

Yes your middleware would not register if it was added after the server was started. I'll add something to the docs. Editing the application in anyway once it has started will produce you defined results.