Re: [PATCH] docs-rst: automatically convert Graphviz and SVG images

[Mauro Carvalho Chehab <mchehab@s-opensource.com>]

Em Thu, 2 Mar 2017 20:52:59 +0100
Daniel Vetter <daniel@ffwll.ch> escreveu:

> On Thu, Mar 02, 2017 at 08:06:39PM +0100, Markus Heiser wrote:
> > Hi Mauro,
> >   
> > > Tested here with the enclosed patch.  
> > 
> > great, big step forward making /media/Makefile smaller ...  thanks a lot!!!!
> >   
> > > It crashed:
> > > Exception occurred:
> > >  File "/devel/v4l/patchwork/Documentation/sphinx/kfigure.py", line 222, in dot2format
> > >    sys.stderr.write(err)
> > > TypeError: write() argument must be str, not bytes
> > > The full traceback has been saved in /tmp/sphinx-err-_1vahbmg.log, if you want to report the issue to the developers.
> > > Please also report this if it was a user error, so that a better error message can be provided next time.
> > > A bug report can be filed in the tracker at <https://github.com/sphinx-doc/sphinx/issues>. Thanks!
> > > Documentation/Makefile.sphinx:69: recipe for target 'htmldocs' failed
> > > make[1]: *** [htmldocs] Error 1
> > > Makefile:1450: recipe for target 'htmldocs' failed
> > > make: *** [htmldocs] Error 2
> > > 
> > > Weird enough, it produced a Documentation/output/media/uapi/v4l/pipeline.svg file.  
> > 
> > I guess that the dot command writes something to stderr. This is captured 
> > by the extension and printed to stderr ...
> > 
> > +def dot2format(dot_fname, out_fname):
> > ...
> > +    exit_code = 42
> > +    with open(out_fname, "w") as out:
> > +        p = subprocess.Popen(
> > +            cmd, stdout = out, stderr = subprocess.PIPE )
> > +        nil, err = p.communicate()
> > +
> > +        sys.stderr.write(err)
> > +
> > +        exit_code = p.returncode
> > +        out.flush()
> > +    return bool(exit_code == 0)
> >   
> > >  File "/devel/v4l/patchwork/Documentation/sphinx/kfigure.py", line 222, in dot2format
> > >    sys.stderr.write(err)
> > > TypeError: write() argument must be str, not bytes  
> > 
> > Do we need this stderr output? For a first test, uncomment the 
> > "sys.stderr.write(err)“ in line 222. Or, if we really need the
> > stderr, try:
> > 
> > -        sys.stderr.write(err)
> > +        sys.stderr.write(str(err))
> > 
> > I this fixes, there is another "sys.stderr.write(err)" in 
> > func svg2pdf(..) which should also fixed ….
> >  
> > +def svg2pdf(svg_fname, pdf_fname):
> > ...
> > +    cmd = [convert_cmd, svg_fname, pdf_fname]
> > +    p = subprocess.Popen(
> > +        cmd, stdout = out, stderr = subprocess.PIPE )
> > +    nil, err = p.communicate()
> > +
> > -        sys.stderr.write(err)
> > +        sys.stderr.write(str(err))
> > +
> > +    exit_code = p.returncode
> > +    return bool(exit_code == 0)  
> 
> Yes, I very much want stderr to be forward.

Yes, error report is required.

> Without that you don't see
> error output from dot or convert, and that makes it impossible to debug
> anything. If I want a direct forwarding of the bytes, how should I do this
> in python? Capturing stderr and then re-dumping it is kinda silly ...

Markus or some other Python programmer may help us with that.

> Note that I copied this pattern from the kernel-doc extension, seems to
> have worked there.

Maybe it is broken there too then, or this is another python API
that changed over time. Here, I'm testing with:
	python3-3.5.2-4.fc25.x86_64

>From here:
	https://docs.python.org/2/library/subprocess.html

communicate returns a tuple.

I used repr(p.communicate()[0], on the code snippet I sent, 
as I copied from an example that I found at:
	https://stackoverflow.com/questions/33295284/python-subprocess-popen-write-to-stderr

Thanks,
Mauro