Config files

The mpas_tools.config module includes the mpas_tools.config.MpasConfigParser class reading, getting, setting, and writing config options and config files.

The mpas_tools.config.MpasConfigParser.add_from_package() method can be used to add the contents of a config file within a package to the config options.

Here is an example from compass .. code-block:: python


‘compass.ocean.tests.global_ocean.make_diagnostics_files’, ‘make_diagnostics_files.cfg’, exception=True)

The first and second arguments are the name of a package containing the config file and the name of the config file itself, respectively. You can see that the file is in the path compass/ocean/tests/global_ocean/make_diagnostics_files (replacing the . in the module name with /). In this case, we know that the config file should always exist, so we would like the code to raise an exception (exception=True) if the file is not found. This is the default behavior. In some cases, you would like the code to add the config options if the config file exists and do nothing if it does not (exception=False).

Ihe MpasConfigParser class also includes methods for adding a user config file, mpas_tools.config.MpasConfigParser.add_user_config(), and other config files by file name, mpas_tools.config.MpasConfigParser.add_from_file().

The mpas_tools.config.MpasConfigParser.copy() method can be used to make a deep copy of the config parser. This is useful in cases where config options should be added or modified without affecting the original config object. For example, this feature is used in MPAS-Analysis to set a reference year as the start year in some analysis without affecting the start year in other analysis.

The mpas_tools.config.MpasConfigParser.set() method has some optional arguments not present in configparser.ConfigParser.set(). The comment argument can be used to add a comment that will be written out above the config option. The comment can cover multiple lines by including a \n character. The comment should not include the # comment character, as this is added automatically. The argument user=True can be used to set “user” config options similar to reading a user config file with mpas_tools.config.MpasConfigParser.add_user_config().

Other methods for the MpasConfigParser are similar to those for configparser.ConfigParser. In addition to get(), getinteger(), getfloat() and getboolean() methods, this class implements mpas_tools.config.MpasConfigParser.getlist(), which can be used to parse a config value separated by spaces and/or commas into a list of strings, floats, integers, booleans, etc. Another useful method is mpas_tools.config.MpasConfigParser.getexpression(), which can be used to get python dictionaries, lists and tuples as well as a small set of functions (range(), numpy.linspace(), numpy.arange(), and numpy.array())

Currently, MpasConfigParser supports accessing a config section using section names as keys, e.g.:

section = self.config['enthalpy_benchmark_viz']
display_image = section.getboolean('display_image')

But it does not allow assignment of a section or many of the other dictionary-like features supported by configparser.ConfigParser.

Comments in config files

One of the main advantages of mpas_tools.config.MpasConfigParser over configparser.ConfigParser is that it keeps track of comments that are associated with config sections and options. There are a few “rules” that make this possible.

Comments must begin with the # character. They must be placed before the config section or option in question (preferably without blank lines between). The comments can be any number of lines.


Inline comments (after a config option on the same line) are not allowed and will be parsed as part of the config option itself.