Re: ReportLab 3.x packaging and deployment

On Tue, Jan 14, 2014 at 11:19:01AM +0000, Andy Robinson wrote:
> On 14 January 2014 11:00, Marius Gedminas <[email protected]> wrote:
> > It would be awesome if I could sudo apt-get install python-reportlab and
> > then somehow make it available in selected virtualenvs, but that's a
> > discussion for another list.
> 
> Dumb questions but can't you...
> 
> 1. sudo apt-get install python-reportlab
> 2. create a virtualenv with no site packages
> 3. make a symlink from the venv's site-packages to the system reportlab?

Yes.

But I generally find

  sudo apt-get build-dep python-reportlab

and then building form source simpler.  (Because I have build scripts
that create the virtualenv and pip install -r requirements.txt for me,
and I don't want to put hacks in the middle of those scripts, and I have
no way to pause the script so I could run a custom command after
virtualenv creation but before pip install tries to pull in ReportLab
via some dependency chain.)

> I concluded long ago that pip can't do everything.  All of our web
> projects (and we have a LOT) have a shell script at the top level to
> build/rebuild the environment.   So we can check if a symlink exists
> and create one if it's missing, and do other "procedural" stuff.

I tend to have Makefiles to build virtualenvs on demand etc.  It helps
that I never have to deploy on Windows.

> A requirements.txt which specifies all dependencies is a wonderful
> thing to have anyway.  And pip is happy enough for pure when you add a
> couple more pure Python packages to tour requirements in an existing
> project overnight.  But it needs a lot of 'nursing through'.   Right
> now I'm working on someone else's financial app needing matplotlib,
> scipy (hence fortran), tables (hence HDF5 which absolutely demands a
> local source build inside the venv) etc etc.

Numpy/scipy are a bit special, but sudo apt-get build-dep helps a lot.

I think people (especially scientists who need things like Numpy/Scipy)
are recommending Conda as a solution for prebuilt binary packages that
match your platform exactly.  I haven't had a chance to try it yet.

Marius Gedminas
-- 
Q:      What's tiny and yellow and very, very, dangerous?
A:      A canary with the super-user password.

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