Jupyterlab comm implementation with tests

Author: diningPhilosopher64

src/jupyter_matlab_kernel/__main__.py

@@ -5,7 +5,7 @@
     from ipykernel.kernelapp import IPKernelApp
 
     from jupyter_matlab_kernel import mwi_logger
-    from jupyter_matlab_kernel.kernel_factory import KernelFactory
+    from jupyter_matlab_kernel.kernels.kernel_factory import KernelFactory
 
     logger = mwi_logger.get(init=True)
 

src/jupyter_matlab_kernel/kernels/__init__.py

@@ -0,0 +1,7 @@
+# Copyright 2025 The MathWorks, Inc.
+
+from .jsp_kernel import MATLABKernelUsingJSP
+from .mpm_kernel import MATLABKernelUsingMPM
+from .kernel_factory import KernelFactory
+
+__all__ = ["MATLABKernelUsingJSP", "MATLABKernelUsingMPM", "KernelFactory"]

src/jupyter_matlab_kernel/base_kernel.py …ter_matlab_kernel/kernels/base_kernel.pysrc/jupyter_matlab_kernel/base_kernel.py renamed to src/jupyter_matlab_kernel/kernels/base_kernel.py src/jupyter_matlab_kernel/base_kernel.py renamed to src/jupyter_matlab_kernel/kernels/base_kernel.py

@@ -28,6 +28,9 @@
 )
 from jupyter_matlab_kernel.mwi_exceptions import MATLABConnectionError
 
+from jupyter_matlab_kernel.kernels.labextension_comm import LabExtensionCommunication
+
+
 _MATLAB_STARTUP_TIMEOUT = mwi_settings.get_process_startup_timeout()
 
 
@@ -75,7 +78,7 @@ def _fetch_jupyter_base_url(parent_pid: str, logger: Logger) -> str:
     return ""
 
 
-def _get_parent_pid() -> int:
+def _get_parent_pid(logger) -> int:
     """
     Retrieves the parent process ID (PID) of the Kernel process.
 
@@ -89,6 +92,8 @@ def _get_parent_pid() -> int:
     """
     parent_pid = os.getppid()
 
+    logger.info("Type ", type(parent_pid), " parent pid ", parent_pid)
+
     # Note: conda environments do not require this, and for these environments
     # sys.prefix == sys.base_prefix
     is_virtual_env = sys.prefix != sys.base_prefix
@@ -141,6 +146,15 @@ def __init__(self, *args, **kwargs):
         # Communication helper for interaction with backend MATLAB proxy
         self.mwi_comm_helper = None
 
+        self.labext_comm = LabExtensionCommunication(self)
+
+        # Override only comm handlers to keep implementation clean by separating
+        # JupyterLab extension communication logic from core kernel functionality.
+        # Other handlers (interrupt_request, execute_request, etc.) remain in base class.
+        self.shell_handlers["comm_open"] = self.labext_comm.comm_open
+        self.shell_handlers["comm_msg"] = self.labext_comm.comm_msg
+        self.shell_handlers["comm_close"] = self.labext_comm.comm_close
+
     # ipykernel Interface API
     # https://ipython.readthedocs.io/en/stable/development/wrapperkernels.html
 

src/jupyter_matlab_kernel/jsp_kernel.py …yter_matlab_kernel/kernels/jsp_kernel.pysrc/jupyter_matlab_kernel/jsp_kernel.py renamed to src/jupyter_matlab_kernel/kernels/jsp_kernel.py src/jupyter_matlab_kernel/jsp_kernel.py renamed to src/jupyter_matlab_kernel/kernels/jsp_kernel.py

@@ -13,7 +13,7 @@
 import aiohttp.client_exceptions
 import requests
 
-from jupyter_matlab_kernel import base_kernel as base
+from jupyter_matlab_kernel.kernels import base_kernel as base
 from jupyter_matlab_kernel import mwi_logger, test_utils
 from jupyter_matlab_kernel.mwi_comm_helpers import MWICommHelper
 from jupyter_matlab_kernel.mwi_exceptions import MATLABConnectionError
@@ -89,7 +89,7 @@ def start_matlab_proxy(logger=_logger):
         pass
 
     # Use parent process id of the kernel to filter Jupyter Server from the list.
-    jupyter_server_pid = base._get_parent_pid()
+    jupyter_server_pid = base._get_parent_pid(logger)
     logger.debug(f"Resolved jupyter server pid: {jupyter_server_pid}")
 
     nb_server = dict()

…/jupyter_matlab_kernel/kernel_factory.py …_matlab_kernel/kernels/kernel_factory.pysrc/jupyter_matlab_kernel/kernel_factory.py renamed to src/jupyter_matlab_kernel/kernels/kernel_factory.py src/jupyter_matlab_kernel/kernel_factory.py renamed to src/jupyter_matlab_kernel/kernels/kernel_factory.py

@@ -3,8 +3,8 @@
 import os
 from typing import Union
 
-from jupyter_matlab_kernel.jsp_kernel import MATLABKernelUsingJSP
-from jupyter_matlab_kernel.mpm_kernel import MATLABKernelUsingMPM
+from jupyter_matlab_kernel.kernels.jsp_kernel import MATLABKernelUsingJSP
+from jupyter_matlab_kernel.kernels.mpm_kernel import MATLABKernelUsingMPM
 
 
 class KernelFactory:

src/jupyter_matlab_kernel/kernels/labextension_comm/__init__.py

@@ -0,0 +1,3 @@
+# Copyright 2025 The MathWorks, Inc.
+
+from .communication import LabExtensionCommunication

src/jupyter_matlab_kernel/kernels/labextension_comm/communication.py

@@ -0,0 +1,55 @@
+# Copyright 2025 The MathWorks, Inc.
+
+from ipykernel.comm import Comm
+
+
+class LabExtensionCommunication:
+    def __init__(self, kernel):
+        self.comms = {}
+        self.kernel = kernel
+        self.log = kernel.log
+
+    def comm_open(self, stream, ident, msg):
+        """Handler to execute when labextension sends a message with 'comm_open' type ."""
+        content = msg["content"]
+        comm_id = content["comm_id"]
+        target_name = content["target_name"]
+        self.log.debug(
+            f"Received comm_open message with id: {comm_id} and target_name: {target_name}"
+        )
+        comm = Comm(comm_id=comm_id, primary=False, target_name=target_name)
+        self.comms[comm_id] = comm
+        self.log.info("Successfully created communication channel with labextension")
+
+    async def comm_msg(self, stream, ident, msg):
+        """Handler to execute when labextension sends a message with 'comm_msg' type."""
+
+        content = msg["content"]
+        data = content["data"]
+        action_type = data["action"]
+        payload = data["data"]
+        comm_id = content["comm_id"]
+        comm = self.comms.get(comm_id)
+
+        if not comm:
+            self.log.error(
+                "Received comm_msg but no communication channel is available"
+            )
+            raise Exception("No Communcation channel available")
+
+        self.log.debug(
+            f"Received action_type:{action_type} with data:{payload} from the lab extension"
+        )
+
+    def comm_close(self, stream, ident, msg):
+        """Handler to execute when labextension sends a message with 'comm_close' type."""
+        content = msg["content"]
+        comm_id = content["comm_id"]
+        comm = self.comms.get(comm_id)
+
+        if comm:
+            self.log.info(f"Comm closed with id: {comm_id}")
+            del self.comms[comm_id]
+
+        else:
+            self.log.warning(f"Attempted to close unknown comm_id: {comm_id}")

src/jupyter_matlab_kernel/mpm_kernel.py …yter_matlab_kernel/kernels/mpm_kernel.pysrc/jupyter_matlab_kernel/mpm_kernel.py renamed to src/jupyter_matlab_kernel/kernels/mpm_kernel.py src/jupyter_matlab_kernel/mpm_kernel.py renamed to src/jupyter_matlab_kernel/kernels/mpm_kernel.py

@@ -9,7 +9,7 @@
 import matlab_proxy_manager.lib.api as mpm_lib
 from requests.exceptions import HTTPError
 
-from jupyter_matlab_kernel import base_kernel as base
+from jupyter_matlab_kernel.kernels import base_kernel as base
 from jupyter_matlab_kernel.mwi_comm_helpers import MWICommHelper
 from jupyter_matlab_kernel.mwi_exceptions import MATLABConnectionError
 

src/jupyter_matlab_kernel/mwi_comm_helpers.py

@@ -1,4 +1,4 @@
-# Copyright 2023-2024 The MathWorks, Inc.
+# Copyright 2023-2025 The MathWorks, Inc.
 # Helper functions to communicate with matlab-proxy and MATLAB
 
 import http
@@ -264,6 +264,9 @@ async def _send_feval_request_to_matlab(self, http_client, fname, nargout, *args
             self.logger.error("Error occurred during communication with matlab-proxy")
             raise resp.raise_for_status()
 
+    async def send_eval_request_to_matlab(self, mcode):
+        return await self._send_eval_request_to_matlab(self._http_shell_client, mcode)
+
     async def _send_eval_request_to_matlab(self, http_client, mcode):
         self.logger.debug("Sending Eval request to MATLAB")
         # Add the MATLAB code shipped with kernel to the Path
@@ -286,6 +289,7 @@ async def _send_eval_request_to_matlab(self, http_client, mcode):
             self.logger.debug(f"Response:\n{response_data}")
             try:
                 eval_response = response_data["messages"]["EvalResponse"][0]
+
             except KeyError:
                 # In certain cases when the HTTPResponse is received, it does not
                 # contain the expected data. In these cases most likely MATLAB has
@@ -296,49 +300,8 @@ async def _send_eval_request_to_matlab(self, http_client, mcode):
                 )
                 raise MATLABConnectionError()
 
-            # If the eval request succeeded, return the json decoded result.
-            if not eval_response["isError"]:
-                result_filepath = eval_response["responseStr"].strip()
-
-                # If the filepath in the response is not empty, read the result from
-                # file and delete the file.
-                if result_filepath != "":
-                    self.logger.debug(f"Found file with results: {result_filepath}")
-                    self.logger.debug("Reading contents of the file")
-                    with open(result_filepath, "r") as f:
-                        result = f.read().strip()
-                    self.logger.debug("Reading completed")
-                    try:
-                        import os
-
-                        self.logger.debug(f"Deleting file: {result_filepath}")
-                        os.remove(result_filepath)
-                    except Exception:
-                        self.logger.error("Deleting file failed")
-                else:
-                    self.logger.debug("No result in EvalResponse")
-                    result = ""
-
-                # If result is empty, populate dummy json
-                if result == "":
-                    result = "[]"
-                return json.loads(result)
-
-            # Handle the error cases
-            if eval_response["messageFaults"]:
-                # This happens when "Interrupt Kernel" is issued from a different
-                # kernel. There may be other cases also.
-                self.logger.error(
-                    f'Error during execution of Eval request in MATLAB:\n{eval_response["messageFaults"][0]["message"]}'
-                )
-                error_message = (
-                    "Failed to execute. Operation may have been interrupted by user."
-                )
-            else:
-                # This happens when "Interrupt Kernel" is issued from the same kernel.
-                # The responseStr contains the error message
-                error_message = eval_response["responseStr"].strip()
-            raise Exception(error_message)
+            return eval_response
+
         else:
             self.logger.error("Error during communication with matlab-proxy")
             raise resp.raise_for_status()
@@ -376,6 +339,54 @@ async def _send_jupyter_request_to_matlab(self, request_type, inputs, http_clien
                 args = args + "," + str(cursor_pos)
 
             eval_mcode = f"processJupyterKernelRequest({args})"
-            resp = await self._send_eval_request_to_matlab(http_client, eval_mcode)
+            eval_response = await self._send_eval_request_to_matlab(
+                http_client, eval_mcode
+            )
+            resp = await self._read_eval_response_from_file(eval_response)
 
         return resp
+
+    async def _read_eval_response_from_file(self, eval_response):
+        # If the eval request succeeded, return the json decoded result.
+        if not eval_response["isError"]:
+            result_filepath = eval_response["responseStr"].strip()
+
+            # If the filepath in the response is not empty, read the result from
+            # file and delete the file.
+            if result_filepath != "":
+                self.logger.debug(f"Found file with results: {result_filepath}")
+                self.logger.debug("Reading contents of the file")
+                with open(result_filepath, "r") as f:
+                    result = f.read().strip()
+                self.logger.debug("Reading completed")
+                try:
+                    import os
+
+                    self.logger.debug(f"Deleting file: {result_filepath}")
+                    os.remove(result_filepath)
+                except Exception:
+                    self.logger.error("Deleting file failed")
+            else:
+                self.logger.debug("No result in EvalResponse")
+                result = ""
+
+            # If result is empty, populate dummy json
+            if result == "":
+                result = "[]"
+            return json.loads(result)
+
+        # Handle the error cases
+        if eval_response["messageFaults"]:
+            # This happens when "Interrupt Kernel" is issued from a different
+            # kernel. There may be other cases also.
+            self.logger.error(
+                f'Error during execution of Eval request in MATLAB:\n{eval_response["messageFaults"][0]["message"]}'
+            )
+            error_message = (
+                "Failed to execute. Operation may have been interrupted by user."
+            )
+        else:
+            # This happens when "Interrupt Kernel" is issued from the same kernel.
+            # The responseStr contains the error message
+            error_message = eval_response["responseStr"].strip()
+        raise Exception(error_message)

src/jupyter_matlab_labextension/jest.config.js

@@ -2,6 +2,18 @@
 module.exports = {
   preset: 'ts-jest',
   testEnvironment: 'node',
-  testMatch: ['**/__tests__/**/*.ts?(x)', '**/?(*.)+(spec|test).ts?(x)'],
+  testMatch: ['**/tests/**/*.ts?(x)', '**/?(*.)+(spec|test).ts?(x)'],
+  testPathIgnorePatterns: ['/node_modules/', '/src/tests/jest-setup.ts'],
   moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx', 'json', 'node'],
-};
+  setupFilesAfterEnv: ['<rootDir>/src/tests/jest-setup.ts'],
+  transform: {
+    '^.+\\.(ts|tsx)$': 'ts-jest'
+  },
+  transformIgnorePatterns: [
+    '/node_modules/(?!(@jupyterlab)/)' // Transform @jupyterlab packages
+  ],
+  moduleNameMapper: {
+    // Mock @jupyterlab/ui-components to avoid ES modules issues
+    '@jupyterlab/ui-components': '<rootDir>/src/tests/mocks/ui-components.js'
+  }
+};