Including Data Plugins

PyDM is built with a flexible architecture such that information from multiple sources can be displayed without changing widget code. This allows widgets to be agnostic of the data source that updates them and focus on the logic of displaying information. PyDM will always import the built-in plugins found in the data_plugins folder, but some advanced users may want to include custom data plugins as well. A mapping of protocol to PyDMPlugin is kept within pydm.data_plugins.plugin_modules and mirrored in PyDMApplication.plugins. This is where the PyDMApplication will determine which plugin to use when you provided it with a channel.

If you would like add a library of plugins from a specific folder for every session, PyDM will check all paths provided by the environment variable $PYDM_DATA_PLUGINS_PATH. This folder will be searched for files that fit the name {}_plugin.py and attempt to load the contained plugin. Each of these files should contain a single PyDMPlugin. For those searching for a more programmatic approach the API is documented below. Take note that all plugins should be registered before the PyDMApplication is launched, otherwise they will not be registered in time for connections to be made.

pydm.data_plugins.add_plugin(plugin: Type[PyDMPlugin]) → Optional[PyDMPlugin]

Add a PyDM plugin to the global registry of protocol vs. plugins

Parameters:

plugin (PyDMPlugin type) – The class of plugin to instantiate

Returns:

plugin – The instantiated PyDMPlugin. If instantiation failed, will return None.

Return type:

PyDMPlugin, optional

pydm.data_plugins.load_plugins_from_path(locations: List[str], token: str = '_plugin.py') → Dict[str, PyDMPlugin]

Load plugins from file locations that match a specific token

Parameters:

• locations (list of str) – List of file locations

• token (str) – Phrase that must match the end of the filename for it to be checked for PyDMPlugins

Returns:

plugins – Dictionary of plugins add from this folder

Return type:

dict