Use Youtube-dl with Flask and uWSGI

[juanektbb]

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Question

I have got a Flask application with a Virtual Environment using uWSGI in Nginx. (Ubuntu 18.04)
I want to download an MP3 using Youtube-dl when accessing a route /test

Case 1: If I run the same program from the terminal, it executes successfully.
Case 2: If I access the route, the program fails with an error telling me to install ffmpeg
Case 3: If I access another route that contains a subprocess to run a separate .py file, it also fails.

The error given by case 2 and 3:

WARNING: BaW_jenozKc: writing DASH m4a. Only some players support this container. Install ffmpeg or avconv to fix this automatically.
ERROR: ffprobe/avprobe and ffmpeg/avconv not found. Please install one.
Traceback (most recent call last):
    File "/home/juan/mp3d/mp3denv/lib/python3.6/site-packages/youtube_dl/YoutubeDL.py", line 2064, in post_process
        files_to_delete, info = pp.run(info)
    File "/home/juan/mp3d/mp3denv/lib/python3.6/site-packages/youtube_dl/postprocessor/ffmpeg.py", line 272, in run
        filecodec = self.get_audio_codec(path)
    File "/home/juan/mp3d/mp3denv/lib/python3.6/site-packages/youtube_dl/postprocessor/ffmpeg.py", line 166, in get_audio_codec

My configuration is very simple as follows:

    ydl_opts = {
        'format': 'bestaudio/best',
        'verbose': True,
        'postprocessors': [{
            'key': 'FFmpegExtractAudio',
            'preferredcodec': 'mp3',
            'preferredquality': '192',
        }],
        'postprocessor_args': [
            '-ar', '16000'
        ],
        'prefer_ffmpeg': True,
    }

    with youtube_dl.YoutubeDL(ydl_opts) as ydl:
        ydl.download(['http://www.youtube.com/watch?v=BaW_jenozKc'])

I have done the obvious:

• sudo apt-get install ffmpeg
• pip install ffmpeg

I believe it is server / enviroment / uWSGI configuration to access ffmpeg from a route.
Would this be related to the PATH or Permissions? - Any suggestion on what should I look at?

I followed this tutorial to configure my server, may this is useful.
https://www.digitalocean.com/community/tutorials/how-to-serve-flask-applications-with-uswgi-and-nginx-on-ubuntu-18-04

[dstftw]

As you've already mentioned this is most likely PATH or permissions.

[juanektbb]

@dstftw Thanks for your reply. I am not really sure how to edit that PATH.

This is my Systemd Unit File for WSGI (/etc/systemd/system/myproject.service):

[Unit]
Description=uWSGI instance to serve myproject
After=network.target

[Service]
User=john
Group=www-data
WorkingDirectory=/home/john/myproject
Environment="PATH=/home/john/myproject/myprojectenv/bin"
ExecStart=/home/john/myproject/myprojectenv/bin/uwsgi --ini myproject.ini

[Install]
WantedBy=multi-user.target

Is this the path I should change?

And this one includes the permissions (~/myproject/myproject.ini):

[uwsgi]
module = wsgi:app

master = true
processes = 5

socket = myproject.sock
chmod-socket = 660
vacuum = true

die-on-term = true