Pedal Pi - Application¶
Pedal Pi - Application is a framework for manager the Pedal Pi. Through it is possible loads Pedal Pi Components to provide a Human Machine Interface (HMI) or even have an opening for other software to consume the features of the Pedal Pi.
The components developed use the API (available through Controllers) to manage the resources of the Pedal Pi.
- Documentation:
- http://pedalpi-application.readthedocs.io/
- Code:
- https://github.com/PedalPi/Application
- Python Package Index:
- https://pypi.org/project/PedalPi-Application
- License:
- Apache License 2.0
Running Application¶
Following are the steps required to set up and run Pedal Pi - Application.
Prepare ambient¶
Install with pip
pip3 install PedalPi-Application
Create the script file that contains the code to run the application (as example start.py)
from application.application import Application
application = Application(path_data="data/", address='localhost')
application.start()
from signal import pause
try:
pause()
except KeyboardInterrupt:
application.stop()
Download, compile and install mod-host. Mod-host is a LV2 host for Jack controllable via socket or command line. It is developed by Mod Devices, a company that also develops professional equipment for musicians.
git clone https://github.com/moddevices/mod-host
cd mod-host
make
make install
Run Application¶
Start audio process. The required settings for your audio card can vary greatly. I recommend that you try different possibilities in order to minimize the latency and number of xruns.
If you do not have any experience with JACK, is recommend the lecture of Demystifying JACK – A Beginners Guide to Getting Started with JACK from Linux Music Production.
# In this example, is starting a Zoom g3 series audio interface
jackd -R -P70 -t2000 -dalsa -dhw:Series -p256 -n3 -r44100 -s &
mod-host &
Finally, start the application
python3 start.py
Extending¶
It’s possible add or extends the Pedal Pi with addiction of Component. A component can provides a Human Machine Interface (HMI) - like Raspberry P0 - or even have an opening for other software to consume the features of the Pedal Pi - like WebService plugin.
See the github Components Project for complete components list.
To add a component in your configuration file, download it and register it before starting the application (application.start()):
pip3 install PedalPi-<component name>
from application.Application import Application
application = Application(path_data="data/", address='localhost')
# Loading component
from raspberry_p0.raspberry_p0 import RaspberryP0
application.register(RaspberryP0(application))
# Start application
application.start()
# Don't stop application
from signal import pause
try:
pause()
except KeyboardInterrupt:
# Stop components with safety
application.stop()
Each component needs a configuration to work. Pay attention to your documentation for details on how to set it up and use it.
Delegating audio processing to other equipment¶
The connection with mod-host is over TCP. So it’s possible to place a machine to perform the processing and another to provide the control services.
- For example, you have a Raspberry Pi B+ and a PC.
- The PC in http://10.0.0.100 will process the audio, then it will execute jack process, mod-host process and the audio interface will be connected to it.
- The RPi will executes Application with Component, like Raspberry P0 component. Raspberry P0 disposes a simple current pedalboard control.
application = Application(path_data="data/", address='10.0.0.100')
Creating a component¶
Subsequently will be added details in the documentation on how to create a component for the Pedal Pi. For now, you can check the blog post Building a Pedal Pi Component - Pedalboard selector
Maintenance¶
Test¶
The purpose of the tests is:
- Check if the notifications are working, since the module plugins manager is responsible for testing the models;
- Serve as a sample basis.
make test
make test-details
Generate documentation¶
This project uses Sphinx + Read the Docs.
You can generate the documentation in your local machine:
make install-docs-requirements
make docs
make docs-see
Changelog¶
Changelog¶
Version 0.4.1 - released 03/15/18¶
- Improve PluginsManager dependency: Now supports path releases
Version 0.4.0 - released 02/18/18¶
Version 0.3.0 - released 05/30/17¶
- Issue #29 - Secure components close
- Issue #30 - Replace print log to logging
- Breaking change: Issues #39 and #5 - Change save method to pluginsmanager (v0.5.0) Autosaver
- Removed BanksDao -> Using now pluginsmanager Autosaver
- Removed Database -> Using now pluginsmanager Persistence
- BanksController, PedalboardController, EffectController, ParamController, CurrentController changes your API
- Issue #41 - Allows current pedalboard is None
- Issue #40 - If current pedalboard index file is wrong, Application now starts with the current pedalboard = None
- Issue #11 - Banks with same name not will be replaced when Application initialize
- Issue #17 - Fixes: Remove bank with current pedalboard will be crash (when reload Application)
- Issue #45 - Add plugins manager v0.5.0 support
- Removed BanksController, PedalboardController, EffectController, ParamController, NotificationController
- Implemented
Application.register_observer(),Application.unregister_observer()
Version 0.2.1 - released 04/14/17¶
Version 0.2.0 - released 04/05/17¶
- Initial release
API¶
Contents:
PedalPi - Application¶
PedalPi - Application - Component¶
Creating a component¶
Subsequently will be added details on how to create a component for the Pedal Pi. For now, you can check the blog post Building a Pedal Pi Component - Pedalboard selector
Component¶
-
class
application.component.component.Component(application)[source]¶ -
close()[source]¶ Method called when the application is requested to quit. Classes components must implement to safely finish their activities.
-
ApplicationObserver¶
CurrentPedalboardObserver¶
PedalPi - Application - Controller¶
Notification scope¶
pluginsmanager can notifies they changes. As an example, if a connection between effects is created, plugins manager notifies its observers about the change.
This is how ModHost and
Autosaver know when a change occurs.
These observers work passively: they only receive updates, not using the pluginsmanager api to change the state of the application.
Man-Machine Interfaces are usually active: they need to change the state of the application. As an example, a button that leaves bypass an effect. They also need to receive notifications, so that the information presented to the user can be updated in accordance with changes made by other interfaces.
In these cases, is necessary in a change notifiers all except the one who caused the change.
As example, a multi-effects uses Raspberry-P1 for physical management and WebService for a controller with Apk controller. If they uses only pluginsmanager, a toggle status effect change in a Raspberry-P1 will informs WebService and unreasonably Raspberry-P1.
A quick review will be given ahead. For more details, see the pluginsmanager observer documentation.
pluginsmanager has a solution to this problem. Defining a observer:
class MyAwesomeObserver(UpdatesObserver):
def __init__(self, message):
self.message = message
def on_bank_updated(self, bank, update_type, **kwargs):
print(self.message)
# Defining others abstract methods
...
Using:
>>> observer1 = MyAwesomeObserver("Hi! I am observer1")
>>> observer2 = MyAwesomeObserver("Hi! I am observer2")
>>>
>>> manager = BanksManager()
>>> manager.register(observer1)
>>> manager.register(observer2)
>>>
>>> bank = Bank('Bank 1')
>>> manager.banks.append(bank)
"Hi! I am observer1"
"Hi! I am observer2"
>>> with observer1:
>>> del manager.banks[0]
"Hi! I am observer2"
>>> with observer2:
>>> manager.banks.append(bank)
"Hi! I am observer1"
Using application, the process changes a bit. Because pluginsmanager does not support the current
pedalboard change notifications, clients should extend from ApplicationObserver,
a specialization that adds this functionality:
class MyAwesomeObserver(ApplicationObserver):
def __init__(self, message):
self.message = message
def on_current_pedalboard_changed(self, pedalboard, **kwargs):
print('Pedalboard changed!')
def on_bank_updated(self, bank, update_type, **kwargs):
print(self.message)
# Defining others abstract methods
...
To correctly register ApplicationObserver, you must use Application.register_observer()
(or Component.register_observer()):
>>> observer1 = MyAwesomeObserver("Hi! I am observer1")
>>> observer2 = MyAwesomeObserver("Hi! I am observer2")
>>>
>>> application.register_observer(observer1)
>>> application.register_observer(observer2)
Note
Registering directly to the pluginsmanager will result in not receiving updates
defined by ApplicationObserver
Using:
>>> manager = application.manager
>>>
>>> bank = Bank('Bank 1')
>>> manager.banks.append(bank)
"Hi! I am observer1"
"Hi! I am observer2"
>>> with observer1:
>>> del manager.banks[0]
"Hi! I am observer2"
>>> with observer2:
>>> manager.banks.append(bank)
"Hi! I am observer1"
Warning
The operations performed by PluginsManager are not atomic. This architectural constraint was based on the experienced experience that one user will use the system at a time. In this way, try not to abuse the concurrence.
If you are having problems while doing this, let us know.
Controller¶
-
class
application.controller.controller.Controller(application)[source]¶ Abstract class for Application controllers.
Extends to offer functionalities for this API. Remember to manually register the extended class in
Application(in private_load_controllersmethod)Parameters: application (Application) – Applicationinstance