Create a new Python Based KNIME Extension: Node not available from extension

[jeffreyli0312]

Hi everyone,

KNIME’s 4.6 update introduced the ability to create custom nodes using Python in VSCode, and I recently updated to version 4.6.3. I want to create some custom nodes using Python development, so I followed the KNIME documentation attached:
Create a New Python based KNIME Extension

Working through Tutorial 1, I completed all prerequisites: conda setup, basic.zip extracted, vscode set up, and KNIME Python Extension Development (Labs) installed. All the required text files config.yml and knime.ini have been modified accordingly, and conda environment set up. After a restart of KNIME, a “My Template” node should appear in my node repository, but it is not there.

Furthermore, after opening the tutorial KNIME example workflow Example_with_Python_node.knwf, KNIME states that “my Template Node” is missing, and prompts me to install the KNIME Python Extension Development (Labs) extension. I already have this installed. KNIME prevents me from navigating further, and displays this error under “Details”:

Cannot complete the request. See the error log for details.
“KNIME Python Extension Development (Labs)” will be ignored because it is already installed.

The current node in my workflow is labelled as “MISSING”, with the below error message in the console:

ERROR LoadWorkflowRunnable Errors during load: Status: Error: Example_with_Python_node 3 loaded with errors
ERROR LoadWorkflowRunnable Status: Error: Example_with_Python_node 3
ERROR LoadWorkflowRunnable Status: Error: Node “My Template Node” not available from extension “KNIME Python Extension Development (Labs)” (provided by “KNIME AG, Zurich, Switzerland”; plugin “org.knime.python3.nodes” is installed)

Hoping to get this package/node imported properly to start development, any help would be greatly appreciated.

Thanks,
-J

[carstenhaubold]

Hey @jeffreyli0312,

Thanks for trying the Python Extension Development feature!

The error you are getting is weird. Have you tried uninstalling the KNIME Python Extension Development (Labs) feature and installing it again?

Best,
Carsten

[jeffreyli0312]

Hi Carsten,

Thanks for the response, unfortunately that did not work immediately. I have some new updates:

The next morning, the “My Template” node magically appeared in my node repository. I was able to follow Tutorial 1 without any issues. However, while attempting to bundle the node, I mistakenly changed a folder name in my file explorer path and changed it back, which caused the KNIME/Python to lose the environment path. As a result, “My Template” node is missing once again from my node repository. Attached is the log error upon opening KNIME.

When opening KNIME, a node appears in my Node repository for a split second, showing up as “Uncategorized” and disappearing.

Thanks,
-J

[carstenhaubold]

Hi @jeffreyli0312,

Well, even if it looks like we’ve just progressed to another error, this one is actually quite a lot easier to understand. Your installation is fine now, that’s a good start. You have configured your knime.ini correctly to point to a config.yml, because it tries to parse your extension. What seems to be off is the path to your conda environment that should be used for the nodes.

Could you check which conda environments you have (e.g. conda env list in the Anaconda prompt). Then, in your config.yml, paste the path as value for the conda_env_path as described here: Create a New Python based KNIME Extension.

As you said you moved some things around, maybe updating the paths fixes your problem?