Implement interrupt_request messages

close #495

* jupyter-base.el (jupyter-session-endpoints): Consider control_port
in the connection info of a session.
(jupyter-channel-from-request-type): New function.

* jupyter-client.el (jupyter-interrupt-kernel): Send an
interrupt_request when the kernel supports it.
(jupyter-handle-interrupt-reply): New client handler.

* jupyter-kernel-process.el (jupyter-kernel): Don't try to create a
launch-able kernel object when the connection info is provided.
(jupyter-zmq-io): Consider the control channel.
(jupyter-interrupt): Raise an error if trying to interrupt a kernel
when the mode of interruption is message based.

* jupyter-monads.el (jupyter-sent): Determine the channel to send on
based off of the request type.
(jupyter-request): Use `jupyter-channel-from-request-type` to check if
the channel of a request is stdin.

* jupyter-repl.el (jupyter-connect-repl): Spoof a valid kernelspec so
that `jupyter-interrupt-kernel` can be used.

* jupyter-zmq-channel-ioloop.el (initialize-instance): Consider the
control channel.
(jupyter-zmq-channel-ioloop--recv-messages): Update documentation.

jupyter-base.el

@@ -430,7 +430,8 @@ fields:
 (cl-defmethod jupyter-session-endpoints ((session jupyter-session))
   "Return a property list containing the endpoints from SESSION."
   (cl-destructuring-bind
-      (&key shell_port iopub_port stdin_port hb_port ip transport
+      (&key shell_port iopub_port stdin_port hb_port control_port
+            ip transport
             &allow-other-keys)
       (jupyter-session-conn-info session)
     (cl-assert (and transport ip))
@@ -439,7 +440,8 @@ fields:
        for (channel . port) in `((:hb . ,hb_port)
                                  (:stdin . ,stdin_port)
                                  (:shell . ,shell_port)
-                                 (:iopub . ,iopub_port))
+                                 (:iopub . ,iopub_port)
+                                 (:control . ,control_port))
        do (cl-assert port) and
        collect channel and collect (funcall addr port)))))
 
@@ -469,6 +471,13 @@ call the handler methods of those types."
   (message-publisher nil)
   (inhibited-handlers nil))
 
+(defun jupyter-channel-from-request-type (type)
+  "Return the name of the channel that a request with TYPE is sent on."
+  (pcase type
+    ((or "input_reply" "input_request") "stdin")
+    ("interrupt_request" "control")
+    (_ "shell")))
+
 ;;; Connecting to a kernel's channels
 
 (eval-when-compile (require 'tramp))

jupyter-client.el

@@ -483,9 +483,19 @@ longer connected to a kernel."
 
 (cl-defmethod jupyter-interrupt-kernel ((client jupyter-kernel-client))
   "Interrupt the kernel CLIENT is connected to."
-  (let ((kaction-sub (jupyter-kernel-action-subscriber client)))
-    (jupyter-run-with-io kaction-sub
-      (jupyter-publish 'interrupt))))
+  (let ((interrupt-mode (jupyter-kernel-action client
+                          (lambda (kernel)
+                            (plist-get
+                             (jupyter-kernelspec-plist
+                              (jupyter-kernel-spec kernel))
+                             :interrupt_mode)))))
+    (if (equal interrupt-mode "message")
+        (jupyter-run-with-client client
+          (jupyter-sent (jupyter-interrupt-request)))
+      (let ((kaction-sub (jupyter-kernel-action-subscriber client)))
+        (jupyter-run-with-io kaction-sub
+          (jupyter-publish 'interrupt))))))
+
 
 ;;; Waiting for messages
 
@@ -1747,6 +1757,10 @@ CLIENT is a kernel client."
 
 (define-jupyter-client-handler shutdown-reply)
 
+;;;; Interrupt
+
+(define-jupyter-client-handler interrupt-reply)
+
 ;;; IOPUB handlers
 
 (define-jupyter-client-handler comm-open ((client jupyter-kernel-client) req msg)

jupyter-kernel-process.el

@@ -91,7 +91,7 @@ Call the next method if ARGS does not contain a :spec or
     (let ((spec (plist-get args :spec))
           (conn-info (plist-get args :conn-info)))
       (cond
-       (spec
+       ((and spec (not conn-info))
         (when (stringp spec)
           (plist-put args :spec
                      (or (jupyter-guess-kernelspec spec)
@@ -114,7 +114,7 @@ Call the next method if ARGS does not contain a :spec or
 (cl-defmethod jupyter-zmq-io ((kernel jupyter-kernel-process))
   (unless (jupyter-kernel-process-connect-p kernel)
     (jupyter-launch kernel))
-  (let ((channels '(:shell :iopub :stdin))
+  (let ((channels '(:shell :iopub :stdin :control))
         session ch-group hb kernel-io ioloop shutdown)
     (cl-macrolet ((continue-after
                    (cond on-timeout)
@@ -385,7 +385,6 @@ See also https://jupyter-client.readthedocs.io/en/stable/kernels.html#kernel-spe
 (cl-defmethod jupyter-restart ((_kernel jupyter-kernel-process))
   (cl-call-next-method))
 
-;; TODO Fallback to interrupt_request on kernel's control channel
 (cl-defmethod jupyter-interrupt ((kernel jupyter-kernel-process))
   "Interrupt KERNEL's process.
 The process can be interrupted when the interrupt mode of
@@ -396,10 +395,13 @@ See also https://jupyter-client.readthedocs.io/en/stable/kernels.html#kernel-spe
                ((cl-struct jupyter-kernel-process spec) kernel)
                ((cl-struct jupyter-kernelspec plist) spec)
                (imode (plist-get plist :interrupt_mode)))
-    (if (or (null imode) (string= imode "signal"))
-        (when (process-live-p process)
-          (interrupt-process process t))
-      (cl-call-next-method))))
+    (cond
+     ((or (null imode) (string= imode "signal"))
+      (when (process-live-p process)
+        (interrupt-process process t)))
+     ((string= imode "message")
+      (error "Send an interrupt_request using a client"))
+     (t (cl-call-next-method)))))
 
 (provide 'jupyter-kernel-process)
 

jupyter-monads.el

@@ -300,15 +300,16 @@ Ex. Subscribe to a publisher and unsubscribe after receiving two
 (defun jupyter-sent (dreq)
   (jupyter-mlet* ((client (jupyter-get-state))
                   (req dreq))
-    (jupyter-run-with-io (jupyter-kernel-io client)
-      (jupyter-do
-        (jupyter-subscribe (jupyter-request-message-publisher req))
-        (jupyter-publish
-          (list 'send
-                (if (jupyter-request-idle-p req) "stdin" "shell")
-                (jupyter-request-type req)
-                (jupyter-request-content req)
-                (jupyter-request-id req)))))
+    (let ((type (jupyter-request-type req)))
+      (jupyter-run-with-io (jupyter-kernel-io client)
+        (jupyter-do
+          (jupyter-subscribe (jupyter-request-message-publisher req))
+          (jupyter-publish
+            (list 'send
+                  (jupyter-channel-from-request-type type)
+                  type
+                  (jupyter-request-content req)
+                  (jupyter-request-id req))))))
     (jupyter-return req)))
 
 (defun jupyter-idle (dreq &optional timeout)
@@ -448,10 +449,7 @@ the callbacks."
 TYPE is the message type of the message that CONTENT, a property
 list, represents."
   (declare (indent 1))
-  (let ((ih jupyter-inhibit-handlers)
-        (ch (if (member type '("input_reply" "input_request"))
-                "stdin"
-              "shell")))
+  (let ((ih jupyter-inhibit-handlers))
     (lambda (client)
       (let* ((req (jupyter-generate-request
                    client
@@ -460,7 +458,8 @@ list, represents."
                    :client client
                    ;; Anything sent to stdin is a reply not a request
                    ;; so consider the "request" completed.
-                   :idle-p (string= ch "stdin")
+                   :idle-p (string= "stdin"
+                                    (jupyter-channel-from-request-type type))
                    :inhibited-handlers ih))
              (pub (jupyter-message-publisher req)))
         (setf (jupyter-request-message-publisher req) pub)

jupyter-repl.el

@@ -2135,7 +2135,14 @@ like the symbol `jupyter-repl-client', which is the default. "
    (jupyter-client
     (jupyter-kernel
      :conn-info file
-     :connect-p t)
+     :connect-p t
+     ;; Interrupting a kernel with a message is the only way to
+     ;; interrupt kernels connected to using a connection file since
+     ;; there is no way of telling what kind of kernel it is that is
+     ;; being connected to using this method.  See
+     ;; `jupyter-interrupt-kernel'.
+     :spec (make-jupyter-kernelspec
+            :plist '(:interrupt_mode "message")))
     client-class)
    repl-name associate-buffer display))
 

jupyter-zmq-channel-ioloop.el

@@ -48,7 +48,7 @@
     (require 'jupyter-zmq-channel-ioloop)
     (push 'jupyter-zmq-channel-ioloop--recv-messages jupyter-ioloop-post-hook)
     (cl-loop
-     for channel in '(:shell :stdin :iopub)
+     for channel in '(:shell :stdin :iopub :control)
      unless (object-assoc channel :type jupyter-channel-ioloop-channels)
      do (push (jupyter-zmq-channel
                :session jupyter-channel-ioloop-session
@@ -64,9 +64,9 @@ message on the channel and print a list with the form
 
     (message CHANNEL-TYPE . MSG...)
 
-to stdout.  CHANNEL-TYPE is the channel on which MSG was received,
-either :shell, :stdin, or :iopub.  MSG is a list as returned by
-`jupyter-recv'."
+to stdout.  CHANNEL-TYPE is the channel on which MSG was
+received, either :shell, :stdin, :iopub, or :control.  MSG is a
+list as returned by `jupyter-recv'."
   (let (messages)
     (dolist (channel jupyter-channel-ioloop-channels)
       (with-slots (type socket) channel