Add and update installation dependencies in documentation

[jeroenlandheer]

On this page: .../v52.5/docs/install.rst

The installation instructions for Alpine do not mention the package python3-dev. This package is needed for CFFI, since this is built from source when you install it via pip.

Hope this helps.

[mikerockett]

Bumped into this as well, for the latest beta. On a similar note, it seems that harfbuzz and zopfli are required, the latter seemingly is specific to Alpine (?).

After fixing (using -dev), and getting the dependencies straight (one by one, after errors), I cannot get v53 beta 2 to run in an Alpine CI environment. It always exits with signal 11 (segfault).

I have the following to setup dependencies:

apk add -q fontconfig-dev gcc gdk-pixbuf-dev harfbuzz-dev jpeg-dev libffi-dev musl-dev \
  pango-dev py3-brotli py3-cffi py3-pillow py3-pip py3-setuptools py3-wheel python3-dev zlib-dev zopfli-dev

Is this correct? I'm thinking something is missing, but not sure what it is as WeasyPrint gets installed correctly, using pip3 -q install WeasyPrint==53.0b2.

Then, output of --info:

/usr/lib/python3.9/site-packages/weasyprint/text/fonts.py:72: UserWarning: FontConfig: No fonts configured. Expect ugly output.
  warnings.warn(
System: Linux
Machine: x86_64
Version: #1 SMP Tue Mar 23 09:27:39 UTC 2021
Release: 5.10.25-linuxkit

WeasyPrint version: 53.0b2
Python version: 3.9.5
Pydyf version: 0.0.3
Pango version: 14805

But, back to the issue opened here, I think that the docs really need to be updated to include instructions for installing globally on various Linux distros, just like the old docs did. Most people will install from source, as OS package managers are generally behind a version or two (see #1384 for a related issue, found with pango). v53 will not land in major OS distros any time soon (a lot of them are still using v51), and finding repos for these things isn't always easy (for the average user, anyway) or convenient.

[liZe]

Bumped into this as well, for the latest beta. On a similar note, it seems that harfbuzz and zopfli are required, the latter seemingly is specific to Alpine (?).

We’ll check this. We shouldn’t have to rely on gcc and all the -dev packages if py3-cffi is installed.

After fixing (using -dev), and getting the dependencies straight (one by one, after errors), I cannot get v53 beta 2 to run in an Alpine CI environment. It always exits with signal 11 (segfault).

That’s probably because of the warning you get with --info. Installing some fonts could fix the problem.

But, back to the issue opened here, I think that the docs really need to be updated to include instructions for installing globally on various Linux distros, just like the old docs did.

You’re right.

[AlexanderNeilson]

I was listening to a Talk Python to Me episode the other day on running docker in production and they were talking about how Alpine linux uses a different C library that isn't the same as how binary wheels are build currently. So this additional requirement may all stem from an inability to use the binary wheels when working with Alpine.

I don't work using Alpine linux nor do I deploy on docker. So I can't talk with much authority however if others are in the same boat this may help guide understanding for documenting this.

[mikerockett]

Thanks @liZe – I'll try installing a font to see if it makes a difference.

[liZe]

(We should take care of the latest comment of #1384 too.)