ontoenv is an environment manager for ontology management. It eventually wants to be a package manager for RDF ontologies and graphs.
- A CLI tool (
cargo install ontoenv-cli) ontoenv, a Rust librarypyontoenv, a Python library
Imagine you have an RDF graph which imports some ontologies in order to use those concepts. Those ontologies might in import other ontologies, and so on.
The design goals of this project are:
- be lightweight: big fancy ontology tools will handle ontology imports automatically, but do so within a heavyweight GUI and usually without an easy-to-use API; I wanted something that could be used in a Python library or a command line tool
- configurable: when doing ontology development, I want to refer to some files locally, and others on the web; I want to be able to control which files are included and which are not.
- fast: I want to be able to quickly refresh my workspace when I make changes to local files.
Specifically, ontoenv looks for patterns like the following inside local ontology files:
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix : <urn:my_ontology/> .
<urn:my_ontology> rdf:type owl:Ontology ;
owl:imports <https://brickschema.org/schema/1.4/Brick>,
<http://qudt.org/2.1/vocab/quantitykind> .When initialized, ontoenv searches for all local files defining ontologies, identifies their dependencies, and then recursively pulls in those dependencies, their dependencies, and so on.
It saves this in a local Oxigraph database inside the local .ontoenv.
- If you have Rust installed, you can install the tool with
cargo install ontoenv-cli - Download a binary from the Releases tab
Begin by initializing an ontoenv workspace in a directory containing some ontology files (Turtle files, etc).
ontoenv init
This may take a couple minutes. ontoenv searches for all local files defining ontologies, identifies their dependencies, and then recursively pulls in those dependencies, their dependencies, and so on. It is possible to adjust which directories ontoenv searches for, which files it traverses, and whether it pulls ontologies from the web.
$ ontoenv init -h
Create a new ontology environment
Usage: ontoenv init [OPTIONS] [SEARCH_DIRECTORIES]...
Arguments:
[SEARCH_DIRECTORIES]... Directories to search for ontologies. If not provided, the current directory is used
Options:
-r, --require-ontology-names Require ontology names to be unique; will raise an error if multiple ontologies have the same name
-s, --strict Strict mode - will raise an error if an ontology is not found
-o, --offline Offline mode - will not attempt to fetch ontologies from the web
-i, --includes <INCLUDES>... Glob patterns for which files to include, defaults to ['*.ttl','*.xml','*.n3']
-e, --excludes <EXCLUDES>... Glob patterns for which files to exclude, defaults to []
-h, --help Print help
Offline mode in particular is helpful when you want to limit which ontologies get loaded. Simply download the ontologies you want, and then enable offline mode.
ontoenv stores its configuration and internal database in a .ontoenv directory placed in directory from where you ran ontoenv init.
Refresh the workspace to account for changes to local files. ontoenv will use the timestamps on the local files to determine which files to load. This means that refreshing the workspace is often much faster than a full initialization.
Refreshing the graph uses the same parameters as given during ontoenv init.
To change these parameters, just run ontoenv init again with the desired flags and parameters.
ontoenv can import all dependencies (immediate and transitive) into a unified graph.
This is often helpful for passing to reasoners or query processors; while many of these can deal with importing multiple graphs, it is much more convenient to have a single file one can ship around.
We refer to the resulting "unified graph" as the imports closure.
ontoenv get-closure <root ontology name> computes the imports closure and places it into an output.ttl file (or a location of your choice).
There are a several flags one can provide for this process
$ Compute the owl:imports closure of an ontology and write it to a file
Usage: ontoenv get-closure [OPTIONS] <ONTOLOGY> [DESTINATION]
Arguments:
<ONTOLOGY> The name (URI) of the ontology to compute the closure for
[DESTINATION] The file to write the closure to, defaults to 'output.ttl'
Options:
-r, --rewrite-sh-prefixes <REWRITE_SH_PREFIXES>
Rewrite the sh:prefixes declarations to point to the chosen ontology, defaults to true [default: true] [possible values: true, false]
-r, --remove-owl-imports <REMOVE_OWL_IMPORTS>
Remove owl:imports statements from the closure, defaults to true [default: true] [possible values: true, false]
-h, --help
Print help
ontoenv list-ontologies will display a list of ontology names in the workspace.
ontoenv dump will print out an alphabetized list of all ontologies in the workspace, their imports, number of triples, and other metadata.
If GraphViz is installed, ontoenv dep-graph will output a PDF graph representation of the imports closure.
pip install pyontoenv
from ontoenv import Config, OntoEnv
from rdflib import Graph
# create config object. This assumes you have a 'brick' folder locally storing some ontologies
cfg = Config(["brick"], strict=False, offline=True)
# can also create an 'empty' config object if there are no local ontologies
# cfg = Config(strict=False, offline=True)
# make the environment
env = OntoEnv(cfg)
# compute closure for a given ontology and insert it into a graph
g = Graph()
env.get_closure("https://brickschema.org/schema/1.4/Brick", g)
# import all dependencies from a graph
brick = Graph()
brick.parse("brick/Brick.ttl", format="turtle")
env.import_dependencies(brick)
# get a graph by IRI
rec = env.get_graph("https://w3id.org/rec")
# add an ontology to a graph by IRI
env.import_graph(brick, "https://w3id.org/rec")
# get an rdflib.Dataset (https://rdflib.readthedocs.io/en/stable/apidocs/rdflib.html#rdflib.Dataset)
ds = env.to_rdflib_dataset()
for graphname in ds.graphs():
graph = ds.graph(graphname)
print(f"Graph {graphname} has {len(graph)} triples")