Making a Docker application

In keeping with the self-hosted/homelab theme of the last post, I decided to try my hand at creating a service to run in a Docker container, namely a local network 'radio station' organiser with a web interface.

The program is written in Python (no surprises there) with the network streaming handled by VLC, the downloading of audio files (playlists) carried out by YouTube-DL, Python module Bottle fulfilling webserver duties and SQLite3 storing information about downloaded playlists and created streams.

The bash commands that are used to start the VLC streams and to download a YouTube playlist are quite specific.

VLC streams are launched in the background, with a never-ending, randomly selected order of file playback to be transcoded to mp3 and streamed via http.

nohup cvlc -vvv ~/Music/$playlist --random --loop --sout "#gather,transcode{vcodec=none,acodec=mp3,ab=128,channels=2,samplerate=44100,scodec=none}:http{mux=mp3,dst=:$port/}" --sout-keep &


Downloads from YouTube also take place in the background and save only the audio files of each downloaded video into a directory for each playlist.

nohup youtube-dl $url --extract-audio --no-overwrites --ignore-errors --audio-format mp3 -o "~/Music/$shorturl/%(title)s.%(ext)s" &

Here's the web UI:

Main screen, shows all streams and playlists -- clicking stream name changes page to that stream's controls, clicking playlist entry opens YouTube link

Stream controls -- status indicator and start, stop, delete

Admin control -- Download playlist, create stream, restart program and remove all program data (files and config)

To create the Docker image, I used the official Debian image off of Docker Hub with the following dockerfile:

FROM debian
RUN apt-get update && apt-get install -y vlc youtube-dl python3 psmisc
RUN sed -i 's/geteuid/getppid/' /usr/bin/vlc
ADD vlc_radio /srv/vlc_radio
RUN chmod a+x /srv/vlc_radio/main.py
WORKDIR /srv/vlc_radio
CMD ["./main.py"]

Here's the program's source code and dockerfile on GitHub.