Manager for persistent data directories

This module abstracts the location of directories for storing persistent data.

The directory for persistent data will be placed under deploy_data_root_dir/1 (multifile) or inside the temporary build directory (see config_common:data_root_dir/1.

See ensure_datadir/2 for usage. This module is handy to select the directory for persdb databases, e.g.:

persistent_dir(db, Dir) :- ensure_datadir('yourapp', Dir).

Usage and interface

Library usage:
:- use_module(library(persdb/datadir)).
Exports:
- Predicates:
  ensure_datadir/2.
- Multifiles:
  deploy_data_root_dir/1.

Documentation on exports

PREDICATEensure_datadir/2

Usage:ensure_datadir(RelPath,Path)

Obtain the absolute path Path for storing persistent data under relative RelPath directory. The directory is created if needed.

Call and exit should be compatible with:
(basic_props:atm/1)RelPath is an atom.
(basic_props:atm/1)Path is an atom.
The following properties should hold at call time:
(term_typing:nonvar/1)RelPath is currently a term which is not a free variable.
(term_typing:var/1)Path is a free variable.

Documentation on multifiles

PREDICATEdeploy_data_root_dir/1

Directory for persistent data on deployment. If this is a relative path, it will be placed under the HOME directory automatically. The predicate is multifile.

Documentation on imports

This module has the following direct dependencies:

System library modules:
datafacts_rt, pathnames, system, system_extra, config_common.
Packages:
prelude, initial, condcomp, assertions, assertions/assertions_basic, basicmodes, fsyntax, datafacts.