Rule-Library Federation Recipe

Added in v0.120.0

Use this recipe when you already have a versioned rule library and want to share it across pg_ripple instances. For the full walkthrough, including a two-instance setup and monitoring examples, see the Rule Library Federation guide.

When to Use This

Rule-library federation fits teams that maintain shared Datalog or SHACL rule sets, such as RDFS entailment, customer deduplication, or compliance checks, and need the same rules installed consistently across environments.

Minimal Flow

  1. Install or create the library on the source instance.
  2. Publish the library with the URL where the HTTP companion serves its stream.
  3. Record a subscription on the target instance.
  4. Ask the target HTTP companion to fetch and install the remote stream.
-- Source instance: publish an installed library.
SELECT pg_ripple.publish_rule_library(
  'rdfs-entailment',
  'https://instance-a.example.com/rule-libraries/rdfs-entailment/stream'
);

-- Target instance: record subscription intent.
SELECT pg_ripple.subscribe_rule_library(
  'https://instance-a.example.com/rule-libraries/rdfs-entailment/stream',
  'rdfs-entailment'
);

# Target HTTP companion: fetch and install the stream.
curl -X POST https://instance-b.example.com/rule-libraries/rdfs-entailment/subscribe \
  -H "Authorization: Bearer $PG_RIPPLE_HTTP_AUTH_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"source_uri":"https://instance-a.example.com/rule-libraries/rdfs-entailment/stream"}'

Notes

  • publish_rule_library() and subscribe_rule_library() are catalog operations; they do not start a background daemon.
  • POST /rule-libraries/{name}/subscribe performs the remote fetch and installs rules into the target instance.
  • The current HTTP fetcher does not forward a separate Authorization header to the source stream. For protected source streams, use a trusted internal route or fetch from an authenticated client.

See Also