4. Plugin development
If you are a user of ESIBD Explorer you can skip this section. Please read on if you want to extend the functionality by adding plugins or adapt the software for a different type of experiment.
The main code does not need to be modified to add support for additional
devices and other features. Instead, you can add Plugin
that will be
automatically integrated into the user interface. In fact, everything
the user sees in ESIBD Explorer is a Plugin
. This section will discuss
the underlying framework that enables implementation of and communication between different
devices
, scans
, and other plugins
.
To add plugins, all you need to do is prepare a plugin file inside a
sub folder of the user defined plugin path. A plugin file is a python
script that defines a providePlugins()
function, which returns one or
multiple plugins
.
Plugins
can be enabled in the plugin dialog
found in Settings after restarting the software. It is
recommended that your custom plugin classes inherit directly from
Plugin
, Device
, Scan
, or from one of the other built-in plugins.
All built-in plugins
can be imported from esibd.plugins
and the corresponding modules in the plugins_internal folder.
Many other helpful classes and methods can be imported from esibd.core
.
If you need to extend the internal plugins just give them another name and make sure to unselect the original one in the plugin manager dialog. Core plugins, like Explorer, Settings, Console, Browser, etc., can also be extended using extended.py and providePlugins.py.
If you want to do something completely different to the already implemented functionality, get in touch and see if we can implement a base class that can be reused for similar projects in the future and keeps your custom plugin code minimal.
4.1. Plugin
Plugins
abstract basic GUI code for devices, scans, and other high level UI elements.
All plugins are ultimately derived from the Plugin
class.
The doc string of the plugin class will be shown in the corresponding help window
unless documentation is implemented explicitly.
4.2. PluginManager
The PluginManager
is responsible for loading all internal and external
Plugins. It catches errors or incompatibilities while loading,
initializing, and closing plugins. Users will only see the plugin selection
interface accessed from the Settings plugin.
The PluginManager
can be accessed from the Console as PluginManager.
It allows plugins to interact by using unique plugin names as attributes, e.g.
self.pluginManager.ISEG or self.pluginManager.DeviceManager.
4.3. Devices
Devices
are used to handle communication with one or more
physical devices, provide controls to configure the device and display live or
previously recorded data. There are input devices (sending input from
the user to hardware) and output devices (reading outputs from
hardware). Note that some input devices may also read back data from
hardware to confirm that the user defined values are applied correctly.
The main interface consists of a list of Channels. By default only the physically relevant information is shown. By entering the advanced mode, additional channel parameters can be configured. The configuration can be exported and imported, though once all channels have been setup it is sufficient to only load values which can be done using a file dialog or from the context menu of an appropriate file in the Explorer. After loading the configurations or values, a change log will be available in the Text plugin to quickly identify what has changed. Each device also comes with a display and a live display. The current values can also be plotted to get a quick overview and identify any unusual values.
4.4. Channels
A channel
represents a virtual or real parameter and manages all data and
metadata related to that parameter. Each device can only have one
type of channel, but channels have dynamic interfaces that allow to
account for differences in the physical backend.
Channels provide a consistent and structured interface to inputs and outputs. In the advanced mode, channels can be duplicated, moved, or deleted. You may also edit channels directly in the corresponding .ini file in the config path.
Channels are accessible from any plugin using getChannelByName()
.
This, and other features like linking channels by equations, depends on the usage of unique and descriptive channel names.
4.5. Scan
Scans
are all sort of measurements that record any number of outputs as a
function of any number of inputs. The main interface consists of a list of
scan settings. Each scan comes with a tailored display
optimized for its specific data format. Scan settings can be imported
and exported from the scan toolbar, though in most cases it will be
sufficient to import them from the context menu of a previously saved
scan file in the Explorer. When all settings are defined and all relevant channels are
communicating the scan can be started. A scan can be stopped at any
time. At the end of a scan the corresponding file will be saved to the
session path. The filename is displayed inside the corresponding graph to
allow to find the file later based on exported figures. Scan files are
saved in the widely used HDF5 file format that allows to keep data and
metadata together in a structured binary file. External viewers, such as
HDFView, or minimal python scripts based on the h5py package can be used
if files need to be accessed externally. Use the
context menu of a scan file to create a template plot file using h5py
and adjust it to your needs.
4.6. DeviceController
Each Device
or Channel
comes with a DeviceController
. The
DeviceController
is not itself a Plugin
. It only abstracts the direct
hardware communication from plugins
allowing them to use minimal and
consistent code that can be adjusted and reused independently of the
hardware. It should do all resource or time intensive communication work
in parallel threads to keep the GUI responsive. Following the
producer-consumer pattern, the DeviceController
reads values from a physical device and assigns
them to the corresponding Channel
. The devices
will collect data from
the Channel
independently. In case you work with time sensitive
experiments this concept will need to be adapted. Feel free to use the
basic functionality provided by DeviceController
or implement
your own from scratch. As the DeviceController
only interacts with your
custom Channel
or Device
, there are no general requirements for
its implementation.