zmq-support.rkt

#lang racket

(provide (all-defined-out))

(require ffi/unsafe
         (prefix-in zmq: "../zeromq/net/zmq.rkt"))

;; Creates a context and passes it to the func
;; when the function returns, it closes the context
(define (call-with-context func)
  (let ([context (zmq:context 1)])
    (dynamic-wind
      void
      (lambda ()
        (func context) (void))
      (lambda ()
        (zmq:context-close! context)))))

;; Creates a context and passes it to the func
;; when the function returns, it closes the context
(define (call-with-socket context type func )
  (let ([socket (zmq:socket context type)])
    (dynamic-wind
      void
      (lambda ()
        (func socket) (void))
      (lambda ()
        (zmq:socket-close! socket)))))

(define (call-with-req-socket context func)
  (call-with-socket
   context 'REQ
   (lambda (socket)
     (func socket))))

(define (call-with-rep-socket context func)
  (call-with-socket
   context 'REP
   (lambda (socket)
     (func socket))))

;; using zmq_proxy to create shared queue
;;http://api.zeromq.org/3-2:zmq-proxy
(define (call-with-shared-queue context func)
  (let ([router-socket (zmq:socket context 'DEALER)]
        [dealer-socket (zmq:socket context 'ROUTER)])
    (dynamic-wind
      void
      (lambda ()
        (func router-socket dealer-socket)
        (zmq:proxy! router-socket dealer-socket)
        (void))
      (lambda ()
        (zmq:socket-close! router-socket)
        (zmq:socket-close! dealer-socket)))))