pipeline

#! /usr/bin/env scheme-script
; -*- mode: scheme -*-

; Getting Started with 'nanomsg'
; Pipeline (A One-Way Pipe)
; from https://github.com/dysinger/nanomsg-examples#pipeline

#!chezscheme

(import (nanomsg) (chezscheme))

(nanomsg-library-init)

(define node0-name "node0")
(define node1-name "node1")

(define (node0 url)
  (define sock (nn-socket AF_SP NN_PULL))
  (nn-bind sock url)
  (let loop ()
    (let ([buf (box #t)])
      (define bytes (nn-recv sock buf NN_MSG 0))
      (printf "NODE0: RECEIVED '~d'~n" (utf8->string (unbox buf))))
    (loop)))


(define (node1 url msg)
  (define sock (nn-socket AF_SP NN_PUSH))
  (define eid (nn-connect sock url))
  (printf "NODE1: SENDING '~d'~n" msg)
  (let ([bytes (nn-send sock (string->utf8 msg) 0)])
    (nn-shutdown sock eid)))

(define argv (command-line-arguments))
(define argc (length argv))

(cond
 [(and (> argc 1) (string=? node0-name (car argv)))
  (node0 (cadr argv))]
 [(and (> argc 2) (string=? node1-name (car argv)))
  (node1 (cadr argv) (caddr argv))]
 [else
  (printf "Usage: pipeline ~d|~d <URL> <ARG> ...'~n" node0-name node1-name)])


#!eof

./pipeline node0 ipc:///tmp/pipeline.ipc & node0=$! && sleep 1
./pipeline node1 ipc:///tmp/pipeline.ipc "Hello, World!"
./pipeline node1 ipc:///tmp/pipeline.ipc "Goodbye."
kill $node0