Nsryjdtyk

I have long used normal python files for configuration purposes. I can include comments (to remind me what an entry was all about if the variable name isn't sufficient) and supports lists and dictionaries.

Now that I need to have something for a customer importing this seems a bit dangerous as it could break the system if they make an error editing by hand.

In the future I want to be able to update the file from within a program, and also be able to edit it with a normal editor ( and prefer not having to match <> or ():

• XML is inappropriate as it is binary in ascii disguise


• .ini files have to little hierarchical structure


• JSON cannot handle comments.

I am now considering adding comments to JSON, but that essentially would require rewriting the parser to preserve comments. And JSON is not that nicely readable.

There is a ConfigObj library for .ini files that preserves comments, but the .ini is to flat for my needs (lists of dicts containing values that are lists of dicts).

Is there some other config file format I should use? Or should I look at parsing my .py files in safe way before importing them (that also allows writing them out again)?

As Chazeon and jme indicate you should take a look at YAML. It supports nested data structures ( list (sequence in YAML), dict (mapping) and various primitives ( integers, float, string, date ).

YAML also supports end-of-line comments ( introduced with #) but the "standard" PyYAML parser mentioned by Chazeon throws these away while reading data in (and cannot write these).

The package ruamel.yaml (of which I am the author) that derives from PyYAML, preserves the comments when doing a round trip (YAML file to python datastructures to YAML file). It also keeps most of the YAML formatting (block vs. one-line for lists and dictionaries).

Indentation however is "standardised" so all block mappings and sequences look the same after the first roundtrip. Indentation defaults to 2 spaces for both, but these can be set separately, as well as that the dash can be "pushed in" within the space before the sequence element using e.g. yaml.indent(mapping=3, sequence=5, offset=2)

Have you considered YAML? It can have comments start with # and some parsers like PyYAML already exsists.

As far as I know, some relatively large programs like MongoDB is using YAML as configuration file, and some programs use YAML to store metadata in front of a file, for example, Pandoc support yaml in front of Markdown and .

For further information you can visit the The Official YAML Website which presented some good examples and a bunch information or the Wikipedia page.

For me (Just my opinion)

I will use JSON since it is small, easy to read and compatible with almost any language and platform.
For comment, I will use some keyword e.g. "Comment" and assign it as a JSON tag. JSON will ignore unused tags anyway.

Example of JSON

{

    "param1" : "value1",

    "param2" : "value2",

}

Example of JSON with my comment

{

    "param1" : "value1",

    "param2" : "value2",

    "Comment" : "My Comment."

}

By the way, from my experience, we can't rely on customer to edit any formatted data JSON, XML, ini or even YAML. They will brake somethings.