Files
shopdb-flask/docs/PLUGIN-QUICKSTART.md
cproudlock 8eb9362452 Phase 4: plugin scaffolding (flask plugin new) with canary tests
Lowers the barrier for sister sites to build their own plugins.
Generated output satisfies the framework contract out of the box.

CLI command (shopdb/plugins/cli.py):
- `flask plugin new <name> --description "..."` generates a plugin
  skeleton under plugins/<name>/. Validates the name against
  CONTRIBUTING.md rules (lowercase letters/digits only, no
  underscores or hyphens, not in the reserved list) and refuses to
  overwrite existing plugins unless --overwrite is passed.
- Output prints the next steps (install, migrate, test).

Scaffolder (shopdb/plugins/scaffolder.py):
- validate_name: enforces the naming rules
- pascal_case: lowercase-to-PascalCase for class names
- scaffold_plugin: copies templates with string.Template
  substitution. Three placeholders: $name, $Name, $description.
  Files with `model.py` in the path get renamed to <name>.py.

Templates (shopdb/plugins/templates/):
- manifest.json.tmpl: name, version 0.1.0, description, core_version
  range >=0.1.0,<1.0.0 (broad enough to survive minor framework bumps)
- plugin.py.tmpl: <Name>Plugin class extending BasePlugin with all
  required hooks implemented (meta from manifest, get_blueprint
  returning the bp, get_models returning the example model). Includes
  on_install hook that seeds the AssetType row.
- models/__init__.py.tmpl + models/model.py.tmpl: Asset extension
  table keyed by assetid with one example field. TODO comment marks
  it as a placeholder.
- api/__init__.py.tmpl + api/routes.py.tmpl: Blueprint with list and
  detail endpoints using the framework's pagination + response helpers.
- schemas/__init__.py.tmpl: marshmallow schema stub.
- tests/__init__.py.tmpl + tests/test_plugin.py.tmpl: smoke tests
  asserting plugin loads, get_blueprint returns Blueprint, get_models
  returns at least one model.
- README.md.tmpl: one-pager for plugin authors with common edits and
  next-step references.

Canary tests (tests/test_plugin_scaffold.py):
- 14 tests asserting the scaffold output passes contract checks.
- Validates name rules (lowercase, reserved, hyphens, digits, etc.)
- Verifies all expected files generated, manifest fields present.
- Loads the generated plugin via PluginLoader (spec_from_file_location
  bypasses the real `plugins` package shadowing).
- Asserts subclasses BasePlugin, get_blueprint returns Blueprint,
  get_models returns model with __tablename__.
- Module-scoped fixture; cleans up sys.modules + SQLAlchemy metadata
  on teardown to avoid cross-test contamination.

Quickstart docs (docs/PLUGIN-QUICKSTART.md):
- 30-minute walkthrough: scaffold -> edit model -> add routes ->
  install -> verify -> add hooks. Cross-links to PLUGIN-HOOKS.md and
  the ADRs. Includes common-errors table.

Test count: 87 -> 101 passing.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-08 17:13:46 -04:00

5.4 KiB

Plugin Quickstart

Build a working shopdb-flask plugin in 30 minutes. This walks through generating, customizing, installing, and testing a plugin from scratch.

For the full hook reference, see PLUGIN-HOOKS.md. For the architectural decisions behind the contract, see migrations/adr/.

Step 1: Generate the skeleton

flask plugin new cameras --description "Tracks shop-floor surveillance cameras"

Output: plugins/cameras/ with manifest, plugin class, example model, example routes, schemas stub, tests, and a README.

The generated plugin already passes the framework's contract tests. Verify before editing:

pytest plugins/cameras/tests/

Step 2: Edit the model

Open plugins/cameras/models/cameras.py. Replace the examplefield placeholder with your domain fields:

class Cameras(BaseModel):
    __tablename__ = 'cameras'

    assetid = db.Column(
        db.Integer,
        db.ForeignKey('assets.assetid', ondelete='CASCADE'),
        primary_key=True,
    )
    streamurl = db.Column(db.String(255), nullable=False)
    resolution = db.Column(db.String(20))
    fps = db.Column(db.Integer)
    poeport = db.Column(db.String(50))
    asset = db.relationship('Asset', backref=db.backref('cameras', uselist=False))

    def to_dict(self):
        return {
            'assetid': self.assetid,
            'streamurl': self.streamurl,
            'resolution': self.resolution,
            'fps': self.fps,
            'poeport': self.poeport,
        }

Note the naming convention: lowercase concatenated, no underscores (streamurl, not stream_url). See CONTRIBUTING.md.

Step 3: Add routes

Open plugins/cameras/api/routes.py. The scaffold provides list and detail endpoints. Add CRUD as needed:

@cameras_bp.route('', methods=['POST'])
@jwt_required()
def create_camera():
    data = request.get_json()

    asset = Asset(assetnumber=data['assetnumber'], name=data['name'], ...)
    db.session.add(asset)
    db.session.flush()

    camera = Cameras(
        assetid=asset.assetid,
        streamurl=data['streamurl'],
        resolution=data.get('resolution'),
    )
    db.session.add(camera)
    db.session.commit()

    return success_response(camera.to_dict(), http_code=201)

For audit logging, use the public helper:

from shopdb.api import audit_log

audit_log(action='created', entitytype='Camera', entityid=asset.assetid, entityname=asset.name)

Step 4: Install the plugin

flask plugin install cameras
flask db migrate -m "Add cameras plugin tables"
flask db upgrade

install runs the plugin's on_install hook (which seeds the AssetType row), registers it in the plugin registry, and runs migrations.

Step 5: Verify it works

flask plugin list

You should see cameras [Enabled].

Run the plugin's tests:

pytest plugins/cameras/tests/

Hit the API:

curl http://localhost:5001/api/cameras

Step 6: Add hooks (optional)

Override hooks on the plugin class as needed. See PLUGIN-HOOKS.md for the full list. Common ones:

Hook Adds
get_searchable_fields Plugin contributes to the global search endpoint
get_navigation_items Plugin shows up in the sidebar nav
get_dashboard_widgets Plugin's dashboard widget appears on the home page
get_collector_schema Plugin accepts external pushes at /api/collector/<name>

Each hook has a default that does nothing. Override only what your plugin needs.

Step 7: Frontend (manual for now)

Backend scaffolding is automated. Frontend is manual until the frontend scaffolding skill ships. Convention:

  • frontend/src/views/cameras/CamerasList.vue
  • frontend/src/views/cameras/CameraDetail.vue
  • frontend/src/views/cameras/CameraForm.vue

Copy from an existing plugin's view files (e.g., frontend/src/views/network/) as a starting point. Update the API client in frontend/src/api/index.js to add cameras endpoints.

Common errors

Symptom Cause Fix
PluginNotFoundError: manifest.json Manifest deleted or moved Restore plugins/<name>/manifest.json
PluginContractError: missing required field manifest.json incomplete Re-add name, version, description
PluginVersionError: requires core_version X but framework is Y Framework upgraded past your range Update core_version in manifest
Table 'cameras' is already defined Two models declared the same __tablename__ Pick a unique table name
Index name collision Two indexes share the same name (SQLite enforces global uniqueness) Prefix index names with table: idx_cameras_streamurl

Next steps

Distribution

If you are building a plugin for a specific GE Aerospace site (sister-site adoption), ship it as its own git repo. The site running shopdb-flask clones or symlinks your plugin into <repo>/plugins/<name>/. See ADR-003.