Python Node Development - Developing multiple nodes

ricciV1 · August 16, 2024, 7:21am

Hello KNIMErs!

Since I started developing my first python nodes I wondered if there is a structure I need to follow when creating my second node?

Can I use the same enviroment?
Should I put the files of my second node into the same enviroment?
Does the “name” in my knime.yml has to be unique?
What do I need to change in the .ini file?
Will the config.yml stay the same or should I start from scratch with the basic.zip like the first time and have 2 config.yml?

Thank you in advance!

MartinDDDD · August 16, 2024, 8:05am

Hey there,

moved this into Node Development Category!

As I also started building my first nodes I can share some experience:

Yes you can use the same environment - obviously if you need additional packages you’ll have to install them into the same environment as well
Yes that works as well
I think in knime.yml etc. you are giving your extension a name and not the node - if you add another node to the same extension then there is no need for modifying the name
If you add another node to the same extension you don’t have to change anything
see above…

Overall it helped me a lot to understand how to structure things when I reviewed the github repo for the geospatial extension:

If you check out there geospatial_extension.py:

github.com

spatial-data-lab/knime-geospatial-extension/blob/main/knime_extension/src/geospatial_ext.py

# The root category of all Geospatial categories
import knime_extension as knext
import sys

# this section is used for things that need to be executed prior the Geopandas lib is imported which happens with the
# import util.knime_utils line

# enforce use of Shapely 2.0 even if PyGEOS is installed which is required by the momepy, segregation and tobler package
import os

os.environ["USE_PYGEOS"] = "0"


import util.knime_utils as knut


# this section is used for things that need to be executed prior any of the nodes is used e.g. global setups such as
# setting lookup directories etc.
def __initialize_pyproj():
    """

This file has been truncated. show original

You see that they keep their nodes in seperate .py files in a nodes folder and then import them:

The logic etc. for each node is defined in the different .py files that get imported

ricciV1 · August 19, 2024, 9:32am

Thank you very much @MartinDDDD for sharing the informations and the repository!

MartinDDDD · August 19, 2024, 10:00am

You’re welcome - hope it helps and good luck with your project!

system · August 26, 2024, 10:00am

This topic was automatically closed 7 days after the last reply. New replies are no longer allowed.