guix-kernel: Get command from 'socket-control'.

* guix-jupyter-kernel.scm (socket-shell): Set options ZMQ_RCVTIMEO to 50.
  (socket-control): Set options ZMQ_RCVTIMEO to 50.
* guix-jupyter-container.scm (shutdown): Modify 'quit' to 'exit'.

guix-jupyter-container.scm

@@ -331,8 +331,7 @@
 (define (shutdown socket uuid header- parent-header
                   metadata content parts kernels count)
   (zmq-close-socket socket-shell)
-  (zmq-destroy-context context)
-  (quit))
+  (exit #t))
 
 ;;
 ;; Dispatch route.

guix-jupyter-kernel.scm

@@ -115,6 +115,9 @@
                        socket-iopub
                        socket-stdin))
 
+(zmq-set-socket-option socket-shell   ZMQ_RCVTIMEO 50)
+(zmq-set-socket-option socket-control ZMQ_RCVTIMEO 50)
+
 ;; Bind sockets to addressess.
 (for-each zmq-bind-socket sockets adresses)
 
@@ -227,7 +230,18 @@
   (heartbeat-handler))
 
 (define (general-handler socket containers count)
-  (let ((parts (zmq-get-msg-parts socket)))
+  ;; FIXME Use 'zmq_poll'.
+  (define (waiting-data socket next)
+    (catch 'zmq-error
+      (λ _
+        (zmq-get-msg-parts socket))
+      (λ stuff
+        (cond
+         ((equal? EAGAIN (cadr stuff))
+          (waiting-data next socket))
+         (else #f)))))
+
+  (let ((parts (waiting-data socket socket-control)))
     (match parts
       ((wire-uuid wire-delimiter     wire-singature wire-header
                   wire-parent-header wire-metadata  wire-content)
@@ -317,8 +331,7 @@
 (define (shutdown socket uuid header- parent-header
                   metadata content parts containers
                   count)
-  (display "Shutdown kernel !\n")
-  (kill-containers containers)
+  (kill-containers containers parts)
   (atexit)
   (exit #t))
 
@@ -344,38 +357,32 @@
 ;; Process exit and signals handler.
 ;;
 
-(define (kill-containers containers)
-  (display "Kill container... ")
+(define (kill-containers containers parts)
+  (display "\nKill container ")
   (let ((list (vlist->list containers)))
-    (define (loop container)
+    (define (loop list)
       (cond
-       ((null? container)
-        (begin
-          (zmq-destroy-context container-context)
-          (display "Done.\n")
-          #t))
+       ((null? list) #t)
        (else
-        (let* ((container (car container))
+        (let* ((container (car list))
                (name      (car container))
-               (pid       (assoc-ref container "pid")))
-          (kill pid SIGTERM)
-          (waitpid pid)
-          (zmq-close-socket (assoc-ref (assoc-ref container "sockets")
-                                       "shell"))
-          (zmq-close-socket (assoc-ref (assoc-ref container "sockets")
-                                       "shell"))
-          (loop (cdr container))))))
-    (loop list)))
+               (pid       (assoc-ref container "pid"))
+               (sock      (assoc-ref container "socket")))
+          (send-to-container containers sock name parts)
+          (zmq-close-socket sock)
+          (display ".")
+          (loop (cdr list))))))
+
+    (loop list)
+    (display " Done.\n")))
 
 (define (atexit)
-  (display "Close connections... ")
   (for-each zmq-close-socket sockets)
-  (zmq-destroy-context context)
-  (display "Done.\n"))
+  (exit #t))
 
 (define (sig-exit-handler signum)
   (atexit)
-  (quit))
+  (exit signum))
 
 (sigaction SIGTERM sig-exit-handler)
 (sigaction SIGINT  sig-exit-handler)