GraphDB load RDF4J custom SPARQL function in Docker image

Question

I'm having trouble loading my RDF4J custom SPARQL function in GraphDB.

I'm running GraphDB 10.2.0 using the Docker image at https://hub.docker.com/r/ontotext/graphdb.

I've followed https://rdf4j.org/documentation/tutorials/custom-sparql-functions/ and created a custom SPARQL function in RDF4J. I've added the SPI configuration as described in the documentation and packaged it up into a JAR file.

I'm running the GraphDB container with the following docker-compose.yml file.

version: "3.8"

services:
  graphdb:
    image: ontotext/graphdb:10.2.0
    volumes:
      - graphdb-data:/opt/graphdb/home
      - ./build/libs/palindrome-1.0-SNAPSHOT.jar:/opt/graphdb/dist/lib/plugins/example-plugin/palindrome-1.0-SNAPSHOT.jar
    ports:
      - 7200:7200
    environment:
      # Note: running GraphDB in DEBUG mode
      GDB_JAVA_OPTS: >-
        -Xmx4g
        -Xms2g
        -Dgraphdb.home=/opt/graphdb/home
        -Dgraphdb.workbench.importDirectory=/opt/graphdb/home/graphdb-import
        -Dgraphdb.workbench.cors.enable=true
        -Denable-context-index=true
        -Dentity-pool-implementation=transactional
        -Dhealth.max.query.time.seconds=600
        -Dgraphdb.append.request.id.headers=true
        -Dreuse.vars.in.subselects=true
        -Dgraphdb.logger.root.level=DEBUG
    networks:
      - graphdb
    profiles:
      - graphdb

volumes:
  graphdb-data:

networks:
  graphdb:

Once GraphDB has started up. I load some data.

@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>.
@prefix ex: <http://example.org/> .

ex:a rdfs:label "step on no pets" .
ex:b rdfs:label "go on, try it" .

And I run the SPARQL query.

PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX cfn: <http://example.org/custom-function/>
SELECT ?x ?label
WHERE {
   ?x rdfs:label ?label .
   FILTER(cfn:palindrome(str(?label)))
}

However, running the query responds with the following error.

Error 500: error
Query evaluation error: Unknown function 'http://example.org/custom-function/palindrome' (HTTP status 500)

I've looked at existing Stackoverflow questions which seem to suggest RDF4J custom functions can work in GraphDB.

Please can someone guide me on how to load a custom SPARQL function written with RDF4J. Thanks in advance.

GraphDB load RDF4J custom SPARQL function in Docker image

0 Answers0