Rework logic for wait_for_ready

Untitled.ipynb

@@ -0,0 +1,111 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "print(1)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "print(1)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "print(1)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "print(1)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "print(1)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "1\n"
+     ]
+    }
+   ],
+   "source": [
+    "print(1)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "1\n"
+     ]
+    }
+   ],
+   "source": [
+    "print(1)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.7.3"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 4
+}

jupyter_client/asynchronous/client.py

@@ -126,14 +126,21 @@ async def wait_for_ready(self, timeout=None):
 
         # Wait for kernel info reply on shell channel
         while True:
+            self.kernel_info()
             try:
                 msg = await self.shell_channel.get_msg(timeout=1)
             except Empty:
                 pass
             else:
                 if msg['msg_type'] == 'kernel_info_reply':
-                    self._handle_kernel_info_reply(msg)
-                    break
+                    # Checking that IOPub is connected. If it is not connected, start over.
+                    try:
+                        await self.iopub_channel.get_msg(timeout=0.2)
+                    except Empty:
+                        pass
+                    else:
+                        self._handle_kernel_info_reply(msg)
+                        break
 
             if not await self.is_alive():
                 raise RuntimeError('Kernel died before replying to kernel_info')

jupyter_client/blocking/client.py

@@ -91,14 +91,21 @@ def wait_for_ready(self, timeout=None):
 
         # Wait for kernel info reply on shell channel
         while True:
+            self.kernel_info()
             try:
                 msg = self.shell_channel.get_msg(block=True, timeout=1)
             except Empty:
                 pass
             else:
                 if msg['msg_type'] == 'kernel_info_reply':
-                    self._handle_kernel_info_reply(msg)
-                    break
+                    # Checking that IOPub is connected. If it is not connected, start over.
+                    try:
+                        self.iopub_channel.get_msg(block=True, timeout=0.2)
+                    except Empty:
+                        pass
+                    else:
+                        self._handle_kernel_info_reply(msg)
+                        break
 
             if not self.is_alive():
                 raise RuntimeError('Kernel died before replying to kernel_info')

jupyter_client/client.py

@@ -102,11 +102,10 @@ def start_channels(self, shell=True, iopub=True, stdin=True, hb=True, control=Tr
         :meth:`start_kernel`. If the channels have been stopped and you
         call this, :class:`RuntimeError` will be raised.
         """
-        if shell:
-            self.shell_channel.start()
-            self.kernel_info()
         if iopub:
             self.iopub_channel.start()
+        if shell:
+            self.shell_channel.start()
         if stdin:
             self.stdin_channel.start()
             self.allow_stdin = True