OSError: [Errno cairo returned CAIRO_STATUS_WRITE_ERROR: b'error while writing to output stream'] 11

[brendabell]

Python 3.7.4
CairoSVG 2.4.2
Mac OS X 10.14.6

Input file: https://gist.github.com/brendabell/408c12703d92868ed73bcdf04cf92ec7

Note that I did include absolute height, width and viewBox. My code is as follows:

result = generator.generate()
text_file = open("{}.svg".format(machine), "w")
text_file.write(result)
text_file.close()
png_file = open("{}.png".format(machine), "w")
cairosvg.svg2png(bytestring=result,write_to=png_file)
png_file.close()

The generated SVG file seems to be perfect. I started getting the error after the following upgrades:

Python 2.7.16 -> 3.7.4
CairoSVG 1.0.22 -> 2.4.2

[liZe]

It works for me. This error happens when you cannot write to your destination file, you should check the rights set on your destination folder (and your destination file if it already exists).

[brendabell]

It works for me. This error happens when you cannot write to your destination file, you should check the rights set on your destination folder (and your destination file if it already exists).

I've confirmed the destination file does not exist. I also know it's not a permissions issue because my script is able to first create the SVG. It also creates the PNG, but the cairo write fails and I'm left with a zero-byte file.

Here's my pip freeze output. Can you verify whether you're using the same or different versions of something?

cairocffi==1.1.0
CairoSVG==2.4.2
certifi==2019.11.28
cffi==1.13.2
cssselect2==0.2.2
defusedxml==0.6.0
Pillow==6.2.1
pipenv==2018.11.26
pycparser==2.19
pyparsing==2.4.6
svgwrite==1.3.1
tinycss2==1.0.2
virtualenv==16.7.9
virtualenv-clone==0.5.3
webencodings==0.5.1

[brendabell]

It works for me. This error happens when you cannot write to your destination file, you should check the rights set on your destination folder (and your destination file if it already exists).

I just found a work-around. Instead of this:

cairosvg.svg2png(file_obj=text_file,write_to=png_file)

I now have this which works:

png_content = cairosvg.svg2png(file_obj=text_file)
png_file.write(png_content)

I think this is further evidence that it's not a permissions problem.

[liZe]

Well… It may be related to #105 / #106, do you use a hardened system?

[L3o-pold]

With this kind of code it fails on a python3.7 docker image

png_content = cairosvg.svg2png(url="http://leopez.ch/glyphicons-halflings-regular.svg", dpi=96)
tmp_png.name.write(png_content)

  File "/usr/local/lib/python3.7/site-packages/cairosvg/__init__.py", line 70, in svg2png


    output_height=output_height)


  File "/usr/local/lib/python3.7/site-packages/cairosvg/surface.py", line 149, in convert


    instance.finish()


  File "/usr/local/lib/python3.7/site-packages/cairosvg/surface.py", line 499, in finish


    self.cairo.write_to_png(self.output)


  File "/usr/local/lib/python3.7/site-packages/cairocffi/surfaces.py", line 648, in write_to_png


    self._pointer, write_func, ffi.NULL))


  File "/usr/local/lib/python3.7/site-packages/cairocffi/__init__.py", line 88, in _check_status


    raise exception(message, status)


OSError: [Errno cairo returned CAIRO_STATUS_WRITE_ERROR: b'error while writing to output stream'] 11

[liZe]

@L3o-pold Do you use a hardened system?

[L3o-pold]

@liZe what do you mean by hardened?

[liZe]

@liZe what do you mean by hardened?

For example using SELinux.

[L3o-pold]

@liZe nop I use https://hub.docker.com/layers/python/library/python/3.7.6-stretch/images/sha256-45a5c2336da3d510b38481f968554e531f21831dbe7438e1f957127b1bc413be as base image

[brendabell]

Well… It may be related to #105 / #106, do you use a hardened system?

Unless Apple has done something really weird I don't know about in OS X 10.14.6, no.

[liZe]

@L3o-pold Your problem is different from @brendabell’s: you have to set a size in your SVG file (see #49).

(CairoSVG should check that and raise an explicit error.)

[L3o-pold]

Thanks for the answer. I have not the hand on the files.

[liZe]

Thanks for the answer. I have not the hand on the files.

http://leopez.ch/glyphicons-halflings-regular.svg is an SVG font, that’s why it has no size. It can’t be rendered by a SVG renderer (you can try to open it in your browser).

[L3o-pold]

@liZe yes I agree, maybe we should have a more adapted error message.

[liZe]

Unless Apple has done something really weird I don't know about in OS X 10.14.6, no.

I didn’t know, but macOS is also impacted by this problem, according to the cffi documentation. This bug is for sure a duplicate of #106, I’ll change its title to include macOS systems.

@liZe yes I agree, maybe we should have a more adapted error message.

Done in CairoSVG’s f4aa9e5 commit.

[shibababa]

Code mistake
×png_file = open("{}.png".format(machine), "w")
○png_file = open("{}.png".format(machine), "wb")