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Shital Shah
Shital Shah

Reputation: 68818

Copying variable to Jupyter kernel from Python script

I wish to do the following:

  1. From Python script, connect to existing Jupyter kernel.

  2. Copy an object available in Python script to Jupyter kernel.

  3. Access that object from Jupyter notebook.

So far I gather that the way to do this is via jupyter_client. I also found related question here: Executing code in ipython kernel with the KernelClient API.

However this question focused on either setting scaler value or running code. How do you copy object to Jupyter kernel instead?

Upvotes: 1

Views: 964

Answers (1)

Shital Shah
Shital Shah

Reputation: 68818

Here's how far I've got:

First, a lot of things have changed since IPython 4.0 and so whatever little of relevant examples out there aren't valid more. To top it of documentation is non existent.

How to instantiate IPython kernel in Python script

You can do something like this:

from jupyter_client import KernelManager

def main():
    km = KernelManager()
    km.start_kernel()

    cf = km.connection_file
    print("To connect a client: jupyter console --existing ", cf)

    kc = km.client()
    kc.start_channels()
    try:
        kc.wait_for_ready()
    except RuntimeError:
        kc.stop_channels()
        km.shutdown_kernel()
        raise

    # executes Python statement to create global variable named d 
    # and assign it value 32
    kc.execute('d=32')

    input("Press Enter to continue...")

if __name__ == '__main__':
    main()

How to connect to IPython kernel from Jupyter Console

Just execute the command printed by above code:

jupyter console --existing <full json filename>

Then if you type d in Jupyter Console, you will see value 32.

How to connect to IPython kernel from Jupyter Notebook

This is still a tough one. The main issue is that Jupyter notebook insist on owning its own kernel and doesn't have any option to connect to an existing kernel. The only way around is to create your own kernel manager class, an example of which is here but it doesn't seem to work with newer IPython. You then invoke notebook by specifying to use your kernel manager class:

jupyter notebook \
  --NotebookApp.kernel_manager_class=extipy.ExternalIPythonKernelManager \
  --Session.key='b""'

This part still isn't working.

Upvotes: 1

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