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Entity Publisher Agent

Overview​

The Entity Publisher Agent manages the lifecycle of NGSI-LD entities in Stellio Context Broker, handling creation, updates, subscriptions, and batch operations for real-time context management.

Features​

  • CRUD Operations: Create, Read, Update, Delete NGSI-LD entities
  • Batch Processing: Bulk operations for multiple entities
  • Temporal Entities: Time-series entity management
  • Subscriptions: Event-driven notifications
  • Entity Relationships: Manage semantic relationships
  • Query Support: Complex entity queries with filters

Architecture​

graph TB
    A[Data Sources] --> B[Entity Publisher]
    B --> C{Operation}
    C -->|Create| D[POST /entities]
    C -->|Update| E[PATCH /entities/:id]
    C -->|Delete| F[DELETE /entities/:id]
    C -->|Batch| G[POST /entityOperations]
    D --> H[Stellio Context Broker]
    E --> H
    F --> H
    G --> H
    H --> I[PostgreSQL + TimescaleDB]

Configuration​

File: config/stellio.yaml

stellio:
  base_url: "http://localhost:8080"
  context: "https://uri.etsi.org/ngsi-ld/v1/ngsi-ld-core-context.jsonld"
  
  batch:
    max_size: 100
    parallel: true
    
  retry:
    attempts: 3
    delay: 5
    
  timeout: 30

Usage​

Create Entity​

from src.agents.context_management.entity_publisher_agent import EntityPublisherAgent

agent = EntityPublisherAgent()

# Create traffic flow entity
entity = {
    "id": "urn:ngsi-ld:TrafficFlowObserved:CAM_001:20251125T103000Z",
    "type": "TrafficFlowObserved",
    "location": {
        "type": "GeoProperty",
        "value": {"type": "Point", "coordinates": [106.7009, 10.7769]}
    },
    "intensity": {"type": "Property", "value": 45},
    "averageVehicleSpeed": {"type": "Property", "value": 35.5, "unitCode": "KMH"}
}

result = agent.create_entity(entity)
print(f"Created: {result.entity_id}")

Update Entity​

# Partial update
agent.update_entity(
    entity_id="urn:ngsi-ld:TrafficFlowObserved:CAM_001",
    attributes={
        "intensity": {"type": "Property", "value": 52},
        "averageVehicleSpeed": {"type": "Property", "value": 32.0}
    }
)

Batch Operations​

# Create multiple entities
entities = [
    {...},  # Entity 1
    {...},  # Entity 2
    {...}   # Entity 3
]

result = agent.batch_create(entities)
print(f"Created: {result.success_count}/{result.total}")

Query Entities​

# Query by type and location
entities = agent.query_entities(
    entity_type="TrafficFlowObserved",
    geo_query={
        "geometry": "Point",
        "coordinates": [106.7009, 10.7769],
        "georel": "near;maxDistance==1000"
    },
    time_query={
        "timerel": "after",
        "time": "2025-11-29T10:00:00Z"
    }
)

API Reference​

Class: EntityPublisherAgent​

Methods​

create_entity(entity: dict) -> CreateResult​

Create new NGSI-LD entity.

update_entity(entity_id: str, attributes: dict) -> bool​

Update entity attributes.

delete_entity(entity_id: str) -> bool​

Delete entity.

batch_create(entities: List[dict]) -> BatchResult​

Create multiple entities.

query_entities(entity_type: str, **filters) -> List[dict]​

Query entities with filters.

Integration Examples​

With NGSI-LD Transformer​

from src.agents.transformation.ngsi_ld_transformer_agent import NGSILDTransformerAgent

transformer = NGSILDTransformerAgent()
publisher = EntityPublisherAgent()

# Transform and publish
entity = transformer.transform_to_ngsi_ld(raw_data, "TrafficFlowObserved")
publisher.create_entity(entity)

License​

MIT License - Copyright (c) 2025 UIP Contributors (Nguyễn Nhật Quang, Nguyễn Việt Hoàng, Nguyễn Đình Anh Tuấn)

See LICENSE for details.