UnicodeEncodeError in Travis for non-ascii chars in command line help.

[HenningTimm]

In one of the argparse help messages of ddrage I use a 'μ' ('\u03bc'). When the test rage --help is run and the parameters should be printed, the test fails:

[...]
[Jul 13 12:10:53] SERR File "/usr/local/lib/python3.5/argparse.py", line 2364, in _print_message
[Jul 13 12:10:53] SERR file.write(message)
[Jul 13 12:10:53] SERR UnicodeEncodeError: 'ascii' codec can't encode character '\u03bc' in position 5183: ordinal not in range(128)
[Jul 13 12:10:53] ERRO Task processing failed: Unexpected exit code [1] of container [b0fdac31d42b step-2e9c8ed4d2], container preserved
[...]

This is most certainly due to the fact that the busybox image has no UTF-8 support, as mentioned in issue #4961. Is there a workaround for this? As I see this I have the following options:

• Remove the non-ascii chars from my messages (I would prefer not to).
• Use a different test than rage --help (I would need to add an option specificlly for this).

Is there any other way? For my own code I can just change this, but how should we handle this in other software?

[yesimon]

Depending on how much unicode you use you may just wrap the failing parts in a try-except and fallback print u instead of μ. It's not the most elegant fix but allows you to support environments purposely without unicode.

[mbargull]

This can now be done with the "extended base" image:

extra:
  container:
    # extended-base generates en_US.UTF-8 locale and sets LC_ALL, LANG properly
    extended-base: True

. We should document this some time; tracking that via bioconda/bioconda-utils#225