Why is the germinal library not shadowing configuration?

user_181452 0
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I'm in the process of writing some characterisation tests for germinal, prior to adding functionality. To do this, I'd prefer to use a let form and temporarily shadow configuration than setq it.

However, this doesn't work the way I expected it to, for some of the configuration. *germinal-host* can be shadowed, but the certificate configuration *germinal-cert* can't:

CL-USER> (let ((germinal:*germinal-cert* "/foo/bar"))
           (print germinal:*germinal-cert*)
           (germinal:start :background nil))

"/foo/bar" ;; Germinal listening on 0.0.0.0 port 1965
gemini-handler error: SSL initialization error: Can't load certificate /etc/germinal/cert.pem
SSL error queue is empty.

Am I missing the correct way of configuring the germinal client during tests? I could just globally setq the values I want, but I'd like the config to be overridden only during tests, hence use of let.

common-lisp
1 Answers

Thanks to some smart folks on the usocket-devel mailing list, I have the answer: restructure the germinal server to add a helper function that returns a closure, closing over the shadowed variables. This closure then has the correct variable values regardless of which thread invokes it:

(defun make-gemini-handler (cert cert-key root-path)
  "Create a Gemini request handler for a specified root path, TLS certificate, and TLS key."
  (lambda (stream) (gemini-handler stream cert cert-key root-path)))

This is invoked from the main thread like so:

  (with-global-context (*germinal-tls-context* :auto-free-p (not background))
    (usocket:socket-server host port (make-gemini-handler *germinal-cert* *germinal-cert-key* *germinal-root*) ()
               :multi-threading t
               :element-type '(unsigned-byte 8)
               :in-new-thread background)))
user_1814520
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