Python __init__.py files

In Python, a file directory becomes a Python package by the presence of a __init__.py file. Even if this file is empty, the directory (which must adhere to Python naming rules) can be used with the import statement if the package is on the search path.

The instrument package relies on these __init__.py files to control the import of Python objects (variables and functions) for command-line use in interactive Bluesky sessions. These files expose various content (while hiding unnecessary content) for the command-line user. Within any python file, you may find a declaration of __all__, a list of the Python object names to be exposed from that Python file.

The order of loading files is controlled by the lines in the __init__.py file. In some cases, the sequence of loading is important.

instrument/collection.py

This file is used to start the instrument package for interactive use with data collection. It can be used with both IPython console sessions and Jupyter Notebook & JupyterLab sessions.

from instrument.collection import *

instrument/queueserver.py

This file is used to start the instrument package for background server use with remote data collection. It is used by a bluesky-queueserver process.

from instrument.queueserver import *