This module provides four classes that may be used as base classes for
storing program runtime configuration with a verbose boolean field.
The classes provide a .diag(func) method that will check the object's
verbose field and, if it is set to a true value, invoke the specified
function and output the message that it returns. If the message is not
expensive to format (e.g. it does not include stringifying elaborate
data structures), the .diag_(msg) method may be used instead.
The ConfigUnfrozen and ConfigUnfrozenStdOut classes are
normal dataclasses, while the Config and ConfigStdOut ones
are frozen.
The Config and ConfigUnfrozen classes will output any
diagnostic messages to the standard error stream, while
the ConfigStdOut and ConfigUnfrozenStdOut ones will output
the diagnostic messages to the standard output stream.
For compatibility with cfg-diag versions 0.1.x and 0.2.x, there is
also a parallel ConfigDiag* class hierarchy; the classes there are
organized in exactly the same way as those in the Config* hierarchy,
but they only provide a single .diag(msg) method that accepts
a fixed, already-built, string instead of a callback function.
These classes are deprecated and will most probably be removed in
a future version of the cfg-diag library.
Subclass the frozen Config class, add a program-specific field:
@dataclasses.dataclass(frozen=True)
class Config(cfg_diag.Config):
"""Runtime configuration for the fribble program."""
path: pathlib.Path
Initialize this class from an argument parser object:
return Config(path=args.path, verbose=args.verbose)
Output a diagnostic message if requested:
cfg.diag_("This will either appear or it will not")
cfg.diag(lambda: f"Here's the thing: {thing!r}")
This module is developed in a GitHub repository. Contact the StorPool support team for information.