60 lines
2.4 KiB
ReStructuredText
60 lines
2.4 KiB
ReStructuredText
*********
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Internals
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*********
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Some of the following notes and details will hopefully be useful when you start
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developing on Mopidy, while some may only be useful when you get deeper into
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specific parts of Mopidy.
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In addition to what you'll find here, don't forget the :doc:`/api/index`.
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Class instantiation and usage
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=============================
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The following diagram shows how Mopidy with the despotify backend and ALSA
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mixer is wired together. The gray nodes are part of external dependencies, and
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not Mopidy. The red nodes lives in the ``main`` process (running an
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:mod:`asyncore` loop), while the blue nodes lives in a secondary process named
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``core`` (running a service loop in :class:`mopidy.core.CoreProcess`).
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.. digraph:: class_instantiation_and_usage
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"spytify" [ color="gray" ]
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"despotify" [ color="gray" ]
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"alsaaudio" [ color="gray" ]
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"__main__" [ color="red" ]
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"CoreProcess" [ color="blue" ]
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"DespotifyBackend" [ color="blue" ]
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"AlsaMixer" [ color="blue" ]
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"MpdHandler" [ color="blue" ]
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"MpdServer" [ color="red" ]
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"MpdSession" [ color="red" ]
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"__main__" -> "CoreProcess" [ label="create" ]
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"__main__" -> "MpdServer" [ label="create" ]
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"CoreProcess" -> "DespotifyBackend" [ label="create" ]
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"CoreProcess" -> "MpdHandler" [ label="create" ]
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"MpdServer" -> "MpdSession" [ label="create one per client" ]
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"MpdSession" -> "MpdHandler" [ label="pass MPD requests to" ]
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"MpdHandler" -> "DespotifyBackend" [ label="use backend API" ]
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"DespotifyBackend" -> "AlsaMixer" [ label="create and use mixer API" ]
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"DespotifyBackend" -> "spytify" [ label="use Python wrapper" ]
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"spytify" -> "despotify" [ label="use C library" ]
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"AlsaMixer" -> "alsaaudio" [ label="use Python library" ]
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Thread/process communication
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============================
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- Everything starts with ``Main``.
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- ``Main`` creates a ``Core`` process which runs the frontend, backend, and
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mixer.
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- Mixers *may* create an additional process for communication with external
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devices, like ``NadTalker`` in this example.
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- Backend libraries *may* have threads of their own, like ``despotify`` here
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which has additional threads in the ``Core`` process.
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- ``Server`` part currently runs in the same process and thread as ``Main``.
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- ``Client`` is some external client talking to ``Server`` over a socket.
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.. image:: /_static/thread_communication.png
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