Run some IPython ZMQ kernel in the background, without an interactive shell. You can connect to that kernel remotely via ZMQ.

Installation (package is on PyPI):

pip install background_zmq_ipython

Usage:

import background_zmq_ipython
background_zmq_ipython.init_ipython_kernel()

The kernel will then run in the background in its own thread. The init will print some message similar to this on stdout:

To connect another client to this IPython kernel, use:
jupyter console --existing kernel-1111.json

Now, after you connected, how to access globals from the main module? E.g. let's say there is a variable a.

• sys.modules["__main__"].a should work. Via sys.modules, you can access all the imported modules. Or just do import mod again.

• Get the stack of all/other frames via sys._current_frames(), and there you can access the globals from other threads as well.

• You can provide user_ns to init_ipython_kernel, e.g:

  init_ipython_kernel(user_ns=globals())
  

  or:

  init_ipython_kernel(user_ns={"main_globals": globals()})
  

  or:

  init_ipython_kernel(user_ns={"a": a})
  

Alternatives / related links:

• pydbattach
• Twisted SSH (example code)
• IPython.embed_kernel in a background thread (example code). This has some issues (e.g. here; messing around with sys.stdout etc).
• This code was introduced in this StackOverflow question, and also discussed in this IPython GitHub issue #8097, but it has become outdated, so this project provides a rewrite / updated code, and the goal was also an easy to install pip package.