The same checks, without an editor

lpg - labeled property graph modeler

Usage:
  lpg check <model.lpg.yaml>
  lpg emit  <model.lpg.yaml> --target <gql|ladybug|linkml|neo4j|owl|pgschema|shacl> [options]
  lpg ids   <model.lpg.yaml>        assign any missing stable element ids
  lpg targets

Options:
  --target <name>       generation target (repeatable)
  --out <dir>           write artifacts to this directory instead of stdout
  --edition <name>      neo4j edition: community (default) or enterprise

check

Resolves the model and its imports, validates it, and prints every diagnostic as file:line:column severity code: message. Exits 1 when the model has errors, 0 otherwise — warnings alone do not fail the run.

$ lpg check social.lpg.yaml
0 error(s), 0 warning(s)

emit

Generates one or more targets. --target is repeatable. Without --out, artifacts go to stdout; with it, each is written as <model-stem>.<target>.<ext> in that directory, which is created if it does not exist.

$ lpg emit social.lpg.yaml --target ladybug --target shacl --out ./schema
schema/social.ladybug.cypher
schema/social.shacl.ttl

The standards targets work the same way, and are what you reach for when the model has to be read by something this project does not own:

$ lpg emit social.lpg.yaml --target gql --target pgschema --target linkml --out ./schema
schema/social.gql.gql
schema/social.pgschema.pgs
schema/social.linkml.yaml

A model with errors produces nothing at all — the command reports them and exits 1 rather than writing a partial artifact. Downgrade warnings are printed to stderr after the artifact list, and each one is also recorded as a comment inside the artifact:

$ lpg emit social.lpg.yaml --target ladybug --out ./schema
schema/social.ladybug.cypher
social.lpg.yaml:26:7 warning [ladybug] downgrade-required: Property
'Person.email' is required, which LadybugDB cannot enforce: it has no
NOT NULL and only the primary key is non-null.

ids

Assigns a stable element id to every node type, edge type, property and mixin that lacks one, editing the model file in place. Useful after hand-writing a model, or after a merge. Existing ids are never rewritten.

$ lpg ids social.lpg.yaml
assigned 14 id(s) in /work/social.lpg.yaml

targets

Prints the registered target names, one per line.

$ lpg targets
gql
ladybug
linkml
neo4j
owl
pgschema
shacl

Options

--target <name>

Which generator to run. Repeat the flag to run several in one pass. An unknown name is an error naming the ones that exist.

--out <dir>

Write artifacts into this directory instead of stdout. Created recursively if missing.

--edition <community|enterprise>

Neo4j edition. Community — the default — cannot enforce existence or node key constraints, so under it those become downgrades and comments.

Exit codes

In continuous integration

Gate the branch on the model staying valid, and on the committed schema staying in sync with it:

name: schema
on: [push, pull_request]

jobs:
  check:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with: { node-version: '22' }
      - run: npm ci

      # Fails the build on any model error.
      - run: npx lpg-modeler-cli check model/domain.lpg.yaml

      # Regenerate and fail if the committed artifacts drifted.
      - run: npx lpg-modeler-cli emit model/domain.lpg.yaml --target ladybug --target shacl --out schema
      - run: git diff --exit-code schema

The second step is the one that matters over time. It turns "someone forgot to regenerate the DDL" from a thing you discover during an incident into a red build.