add a kernel that priorly links to a existing matlab engine

Author: RibomBalt

.gitignore

@@ -5,3 +5,5 @@ build/
 dist/
 *.pyc
 .*.swp
+matlab_kernel/matlab/
+matlab_kernel/matlab_connect/

MANIFEST.in

@@ -1,4 +1,4 @@
 include versioneer.py
 include matlab_kernel/_version.py
-include matlab_kernel/kernel.json
+include matlab_kernel/kernel_template.json
 recursive-include matlab_kernel *.png

matlab_kernel/kernel.py

@@ -28,7 +28,7 @@ class MatlabExecutionError(Exception):
 
 from . import __version__
 
-
+IS_CONNECT = "connect-to-existing-kernel" in os.environ.keys()
 class _PseudoStream:
 
     def __init__(self, writer):
@@ -39,9 +39,10 @@ def get_kernel_json():
     """Get the kernel json for the kernel.
     """
     here = os.path.dirname(__file__)
-    with open(os.path.join(here, 'kernel.json')) as fid:
+    kernel_name = 'matlab_connect' if IS_CONNECT else 'matlab'
+    with open(os.path.join(here, kernel_name ,'kernel.json')) as fid:
         data = json.load(fid)
-    data['argv'][0] = sys.executable
+    # data['argv'][0] = sys.executable
     return data
 
 
@@ -79,10 +80,16 @@ def _matlab(self):
         Matlab engine not installed:
         See https://www.mathworks.com/help/matlab/matlab-engine-for-python.htm
         """)
-        try:
-            self.__matlab = matlab.engine.start_matlab()
-        except matlab.engine.EngineError:
-            self.__matlab = matlab.engine.connect_matlab()
+        if IS_CONNECT:
+            try:
+                self.__matlab = matlab.engine.connect_matlab()
+            except matlab.engine.EngineError:
+                self.__matlab = matlab.engine.start_matlab()
+        else:
+            try:
+                self.__matlab = matlab.engine.start_matlab()
+            except matlab.engine.EngineError:
+                self.__matlab = matlab.engine.connect_matlab()
         # detecting the correct kwargs for async running
         # matlab 'async' param is deprecated since it became a keyword in python 3.7
         # instead, 'background' param is available and recommended since Matlab R2017b

matlab_kernel/kernel.json matlab_kernel/kernel_template.jsonmatlab_kernel/kernel.json renamed to matlab_kernel/kernel_template.json

@@ -1,4 +1,7 @@
 import glob
+import json
+import os
+import sys
 from setuptools import setup, find_packages
 
 with open('matlab_kernel/__init__.py', 'rb') as fid:
@@ -9,12 +12,35 @@
             break
 
 DISTNAME = 'matlab_kernel'
+
+# generating kernel.json for both kernels
+os.makedirs(os.path.join(DISTNAME, 'matlab'), exist_ok=True)
+with open(os.path.join(DISTNAME, 'kernel_template.json'), 'r') as fp:
+    matlab_json = json.load(fp)
+matlab_json['argv'][0] = sys.executable
+with open(os.path.join(DISTNAME, 'matlab','kernel.json'), 'w') as fp:
+    json.dump(matlab_json, fp)
+
+os.makedirs(os.path.join(DISTNAME, 'matlab_connect'), exist_ok=True)
+with open(os.path.join(DISTNAME, 'kernel_template.json'), 'r') as fp:
+    matlab_json = json.load(fp)
+matlab_json['argv'][0] = sys.executable
+matlab_json['display_name'] = 'Matlab (Connection)'
+matlab_json['name'] = "matlab_connect"
+matlab_json['env'] = {'connect-to-existing-kernel': '1'}
+with open(os.path.join(DISTNAME, 'matlab_connect','kernel.json'), 'w') as fp:
+    json.dump(matlab_json, fp)
+
 PACKAGE_DATA = {
     DISTNAME: ['*.m'] + glob.glob('%s/**/*.*' % DISTNAME)
 }
 DATA_FILES = [
     ('share/jupyter/kernels/matlab', [
-        '%s/kernel.json' % DISTNAME
+        '%s/matlab/kernel.json' % DISTNAME
+     ] + glob.glob('%s/images/*.png' % DISTNAME)
+    ), 
+    ('share/jupyter/kernels/matlab_connect', [
+        '%s/matlab_connect/kernel.json' % DISTNAME
      ] + glob.glob('%s/images/*.png' % DISTNAME)
     )
 ]