How can I pass *.py to pycco via tox?

Question

The following command works:

$ pycco *.py
# generates literate-style documentation
# for all .py files in the current folder

And the following snippet in my tox.ini file works as expected:

[testenv:pycco]
deps =
    pycco
commands =
    pycco manage.py
# generates literate-style documentation
# for manage.py

But if I try to use a glob:

[testenv:pycco]
deps =
    pycco
commands =
    pycco *.py

...I get the following error:

  File "/home/user/Documents/project/.tox/pycco/lib/python3.7/site-packages/pycco/main.py", line 79, in generate_documentation
    code = open(source, "rb").read().decode(encoding)
FileNotFoundError: [Errno 2] No such file or directory: '*.py'

How can I pass *.py to pycco via tox?

score 4 · Answer 1 · answered May 31 '20 at 08:16

The problem here is that pycco does not support glob expansions. What makes pycco *.py work is that before the execution happens the shell actually transforms *.py to actual files; and then passes that to the OS to run it.

When tox runs your command there's no shell involved, so whatever you write is as is passed on to the OS, so now pycco actually gets as argument *.py hence the error.

You can work around this by either explicitly listing the file paths or using the python interpreter to do the expansion:

python -c 'from glob import glob; import subprocess; subprocess.check_call(["pycco"] + glob("*.py"))'

Put the above command inside your tox commands and things will work now as python is now the shell doing the expansion of "*.py" to actual files list.

I appreciate the pure python solution :) – lofidevops Jun 01 '20 at 15:10 — lofidevops, Jun 01 '20 at 15:10

lofidevops · Accepted Answer · 2020-06-01T15:10:24.963

3

You cannot do this directly because pycco does not (currently) support glob expansions. Instead you can create a shell script execute_pycco.sh as follows:

#!/bin/sh

pycco *.py

Update tox.ini as follows:

[testenv:pycco]
deps =
    pycco
commands =
    ./execute_pycco.sh

You will now execute your shell script in the "pycco" environment created by tox. This method also allows you to define more elaborate scripts:

#!/bin/sh

filelist=$( find . -name '*.py' | grep -v ".tox" )
# make a list of all .py files in all subfolders,
# except the .tox/ subfolder

pycco -ip $filelist
# generate literate-style documentation for all
# files in the list

edited Jun 01 '20 at 15:10

answered May 25 '20 at 17:00

lofidevops

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Comments on downvotes would be appreciated. Allergic to shell scripts? The OP is certainly satisfied ;) Obviously the ideal solution would be an enhancement in pycco, but that's out of scope for Q&A. – lofidevops Jun 03 '20 at 00:34

How can I pass *.py to pycco via tox?

2 Answers2