voyandz 0.2.4

Voyoffnik Andzej - an AV HTTP piping server

Copyright (c) 2018, 2020 - 2021 Robikz [e-mail]

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

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Description: Voyoffnik Andzej ================

    Voyoffnik Andzej (voyandz) is a real-time AV streaming server akin to
    the discontinued `ffserver`. Its primary purpose is to enable network
    streaming of audio, video or audio & video in form of continuous,
    non-seekable streams. The source feed can be any feed that can be
    provided in a streamable form through a preinstalled program such as
    `ffmpeg`. The output stream can be any stream that can be produced by
    a preinstalled program such as `ffmpeg`. Voyoffnik Andzej itself
    doesn't delve into codec details, but merely deals with piping.
    
    `ffmpeg` not attached.
    
    Home page: https://github.com/Zalewa/voyandz/
    
    Installation
    ============
    
    ```
      pip3 install voyandz
    ```
    
    Then run:
    
    ```
      voyandz -h
    ```
    
    Current State
    =============
    
    At current stage voyandz is already usable. It is possible to prepare
    configuration file that will create a usable pipeline. HTTP clients,
    such as browsers or command line downloaders, can be used to connect
    to stream endpoints and download the data produced by voyandz.
    voyandz will work with as many input feeds and HTTP clients as possible
    until it hits soft limits such as CPU power or throughput.
    
    It is currently untested how voyandz will behave during long-time
    operation or under heavy usage.
    
    
    What works
    ----------
    
    - Home page, stats page - HTML, config dump - dumps config in JSON format.
    - Reading and parsing a config-file with defined streams and feeds.
    - Piping feeds to streams and then to HTTP clients; creating pipelines.
    - YAML configuration files allowing to define transcoding commands, mimetypes,
      client exclusive or shared streams, listen port, listen host.
    - A "screenshot" stream that produces one picture and closes connection.
    - Logging stderr of commands to a configured logdir.
    
    
    Unstable
    --------
    
    - Config format.
    - API.
    
    
    TODO
    ----
    
    - Config documentation.
    - Config command templating; command args; allow to declare
      multiple similar feeds and streams without having to copy
      and paste the same text all over the config file.
    - Code documentation (docstrings).
    - Limit stderr logfiles to a set size, even
      though it should be logrotate's job.
    - Daemon mode (in the systemd era, should I even be concerned?)
    - Dead feed resurrection.
    
    
    Development
    ===========
    
    Requirements:
    
    - Python 3
    - virtualenv
    - make (optional)
    
    Create virtual env, install dependencies, link the application:
    
    ```
      python3 -m venv venv
      . venv/bin/activate
      make init
      make dev
    ```
    
    To start in development mode:
    
    ```
      FLASK_ENV=development voyandz -f config/minimal
    ```
    
    Cleaning:
    
    ```
      make clean
      rm -rf venv
    ```
    
    Repository Structure
    ====================
    
    Project file structure should adhere to the practices
    recommended for Python and Flask projects.
    
    ```
      .
      |- config - example configuration files
      |- sandbox - development scraps, experiments
      \- voyandz - application code
    ```
    
    Name
    ====
    
    V stands for Video, A stands for Audio, ff implies purpose.
    The rest is gibberish. Short name is `voyandz`, all lower-case.
    
    Troubleshooting
    ===============
    
    **Problem:** Running on Linux and getting
    "cannot modify pipe size: [Errno 1] Operation not permitted"
    error upon heavy load.
    
    **Solution:**
    
    voyandz makes extensive use of pipes. To improve piping performance,
    the size of those pipes is increased using `F_SETPIPE_SZ` `fcntl` calls.
    However, Linux kernel imposes a limit on non-root users on how much
    memory can be consumed by the pipes by each user. This limit is
    controlled through a kernel parameter
    
    ```
      fs.pipe-user-pages-soft
    ```
    
    The value of this parameter is expressed in *pages*, which means the total
    allowed size is at least 4kB times this value. You can read more at:
    https://patchwork.kernel.org/patch/8055531/
    
    voyandz will continue to operate even if the limit is breached, but all
    pipes that try to go above the limit will actually be limited to the
    size of one page. Once usage drops and old pipes are closed, new pipes
    recover the capability to increase their sizes.
    
    To allow more pipes to be opened with increased size do one of those:
    
    * `sudo sysctl fs.pipe-user-pages-soft=65536` to increase the limit;
      Choose a value right for you if you think 65536 is still not enough.
    
    * `sudo sysctl fs.pipe-user-pages-soft=0` to disable the limit completely
    
    To persist this value between reboots add it to `/etc/sysctl.conf` or
    `/etc/sysctl.d/`.
    
    More info: http://man7.org/linux/man-pages/man7/pipe.7.html
    
    Keywords: pipe-user-pages-soft, PermissionError, Operation not permitted

Platform: UNKNOWN