Py-knack

Command line interface framework

Knack is a Python command line parsing framework. Knack is built around the following patterns

• Be consistent with POSIX tools.
• CLI success comes from ease and predictability of use so be consistent.
• Support Piping and output direction to chain commands together.
• Work with GREP, AWK, JQ and other common tools and commands.
• Support productivity features like tab completion and parameter value completion.
• Commands should follow a “[noun] [noun] [verb]” pattern.
• For nouns that only support a single verb, the command should be named as a single hyphenated verb-noun pair.
• Commands should support all output types be consistent.
• Exceptions are okay if only a ‘raw’ format makes sense e.g. XML.
• Commands and arguments should have descriptions.
• Include examples for the less straightforward commands.
• Commands should return an object or dictionary, not strings/bools/etc.; logging.info”Upload of myfile.txt successful” NOT return “Upload successful”.
• Log to ERROR or WARNING for user messages; don’t use print function by default it goes to STDOUT.
• STDOUT vs. STDERR STDOUT is used for actual command output. Everything else to STDERR e.g. log/status/error messages.