About

What does it do

larigira integrates with MPD (Music Player Daemon) and prevents your playlist from running empty. It also has powerful support for “events”: audio that must be played at some time.

Features

  • Simple to install

  • WebUI

  • modular event system

Architecture

larigira delegates all the music playing business to MPD. It relies on tinydb as a db: it’s actually just a json file, to achieve simplicity and flexibility. By default it is stored in ~/.config/larigira/db.json

Code structure and core concepts

The code is heavily based on gevent: almost everything is a greenlet.

alarm

An alarm is a specification of timings. It is “something that can generate times”. For example { 'kind': 'single', 'timestamp': 1234567890 } generates a single time (February 14, 2009 00:31:00), while { 'kind': 'frequency', 'interval': 10, 'start': 1234567890 } generates infinite times, one every 10 seconds, starting from February 14, 2009 00:31:00.

action

An action is a specification of audio. It is “something that can generate a list of audio files”. For example, { 'kind': 'randomdir', 'paths': ['/my/dir', '/other/path'] } will pick a random file from one of the two paths.

Its main atribute is kind. The kind essentialy specifies the function that will be run among a predefined set of Audiogenerators . Every other attribute is an argument to the specified audiogenerator.

event

An event is an alarm plus a list of actions. At given times, do those things

The main object is larigira.mpc.Controller, which in turn uses larigira.mpc.Player to control MPD. How does it know what to do? there are two main flows: the continous playlist filling and the alarm system.

Continous playlist

larigira.mpc.Controller has a “child” called larigira.mpc.MpcWatcher. It watches for events on the playlist; when the playlist is changed it notifies Controller, which in turn will check if the playlist has enough songs. If that’s the case, it will run an audiogenerator, and add the resulting audio at the bottom of the playlist.

Alarm system

There is a DB. The lowest level is handled by TinyDB. larigira.event.EventModel is a thin layer on it, providing more abstract functions.

There is a Monitor, which is something that, well, “monitors” the DB and schedule events appropriately. It will check alarms every EVENT_TICK_SECS seconds, or when larigira received a SIGALRM (so pkill -ALRM larigira might be useful for you).

You can view scheduled events using the web interface, at /view/status/running. Please note that you will only see scheduled events, which are events that will soon be added to playlist. That page will not give you information about events that will run in more than 2 * EVENT_TICK_SECS seconds (by default, this amounts to 1 minute).