Clack with fcgi doesn't work on stdin

[nbtrap]

I can't get clack to do anything when passing :server :fcgi :fd 0 to CLACKUP.It works when I do a bare call to CL-FASTCGI::SERVER-ON-FD with a random callback function, but when I go through clack, the callback function is never called.

Any suggestions?

[fukamachi]

Don't specify :fd unless you'd like to use an existing socket to listen.

[nbtrap]

I understand that. In fact, the FastCGI spec says that the server is supposed to connect to the application with fd 0 already opened as a socket, on which the application then calls accept(2). It's precisely what I want to do, but it doesn't work.

[nbtrap]

Edit: It doesn't work when I use Clack. When I use just bare fastcgi, it works. Looking at the code, I can't figure out what substantial difference there is in the call(s) to fastcgi.

[fukamachi]

Write the code here. Does your Lisp implementation support threads?

[nbtrap]

Works:

(in-package :cl-nbtrap)

(defun app (req)
  (multiple-value-bind (status-code headers content)
      (funcall (get-handler-for req) req)
    (sb-fastcgi:fcgx-puts req
                          (with-output-to-string (s nil)
                            (when status-code
                             (format s "Status: ~D ~A~%" status-code (http-status-reason status-code)))
                            (loop for header in headers do
                                 (format s "~:(~A~): ~A~%" (car header) (cadr header)))
                            (format s "~%~A" content)))))

(defun get-handler-for (req)
  (declare (ignore req))
  #'generic-handler)

(defun generic-handler (req)
  (declare (ignore req))
  (values 200 '((:content-type "text/html"))
          (html/standard-page ("Coming Soon")
            (:h1 (:a :href "mailto:nbtrap@nbtrap.com") "Coming Soon"))))

(defun run-with-fastcgi (&optional load-path)
  (if load-path
      (sb-fastcgi:load-libfcgi load-path)
      (sb-fastcgi:load-libfcgi))
  (sb-fastcgi:simple-server #'app))

Doesn't work:

(in-package :cl-nbtrap)

(defun app (env)
  (declare (ignore env))
  `(200
    (:content-type "text/html")
    (,(html/standard-page
         ("Coming soon")
       (:h1 (:a :href "mailto:nbtrap@nbtrap.com" "Coming soon."))))))

(defun run-app (&rest args &key (server :hunchentoot) &allow-other-keys)
  (apply #'clack:clackup #'app :server server args))

The first example works with sb-fastcgi and cl-fastcgi. In the latter example, I call (run-app :server :fcgi :fd 0), which ends up calling CL-FASTCGI::SERVER-ON-FD, which is the same function that is eventually called in the working example.

Yes, I'm running a working threaded implementation.

[fukamachi]

In the latter example, I call (run-app :server :fcgi :fd 0), which ends up calling CL-FASTCGI::SERVER-ON-FD, which is the same function that is eventually called in the working example.

Could you tell me what happens when you call (run-app :server :fcgi :fd 0)?

[nbtrap]

So far as I can tell, control reaches __BEGIN__ but never reaches __END__:

(defun server-on-fd (func fd &key (flags 0))
  (fcgx-init)
  __BEGIN__
  (with-foreign-object (req 'fcgx-request)
    (fcgx-init-request req fd flags)
    (do ((rc (fcgx-accept req) (fcgx-accept req)))
        ((< rc 0) "ACCEPT ERROR")
      __END__
      (funcall func req)
      (fcgx-finish req))))

[nbtrap]

Other than that, I can't tell. I'm not getting any error message or entering the debugger.

[nbtrap]

Any idea what might be going wrong?

[fukamachi]

Honestly, I have no idea. The only difference is, Clack always makes a thread. Have you tried Clack.Handler.Fcgi with bt:make-thread deleted?

[nbtrap]

I believe I did.

If you can't figure it out, I may spend some more time on it. I want to write my web sites/apps in lisp, and this seems like the most viable option, but the shared hosting service I use doesn't let me run my own server. Fcgi is my only option at this point.