[bug#53388] New package: gallery-dl

[Leo Famulari <leo@famulari.name>]

On Thu, Jan 20, 2022 at 05:42:17PM +0000, Bird wrote:
> > The README says it can use ‘youtube-dl’ or ‘yt-dlp’ for vide downloads
> > and ‘ffmpeg‘ for some conversion, so maybe these could be added?
> >
> > Also, propagation can lead to profile collisions which can be
> > complicated to resolve, so can this be made a regular input instead of
> > a propagated input?  Some wrap-program might be necessary.
> 
> Can programs call to regular inputs that are not propagated?  Since
> gallery-dl will need ffmpeg and python-requests (and possibly yt-dlp),
> would it need to be in user's profile?

They can, but they need to learn how to find them. Usually that happens
by making the package record the "store path" of the input at
build-time.

On the other hand, propagated-inputs appear on $PATH, so if the calling
program does the normal thing it will find them.

But, the drawback of propagating, for example, FFmpeg, is that it makes
it impossible for users to `guix install` a custom FFmpeg package
alongside the propagated FFmpeg.

> >> +    (home-page "https://github.com/mikf/gallery-dl")

I looked at the source code, and this program respects some
configuration options to find the location of youtube-dl and ffmpeg:

https://github.com/mikf/gallery-dl/blob/master/docs/configuration.rst#ugoiraffmpeg-location

It's a matter of opinion but, to me, both of those programs are things
that users may customize or choose particular versions of, so it's okay
to expect users to install them and configure gallery-dl properly.

If we want to improve this package in that regard... that's for a
followup patch!