NGSI-LDES

Open data API for NGSI-LD context brokers

How does it work

NGSI-LDES applies the concept of a Linked Data Event Stream (LDES) on an NGSI-LD temporal interface. This way, consumers can easily replicate and synchronize with the entities provided by a context broker, while increasing the scalability of the broker.

Instead of providing expensive services, such as filtering, to the consumer, NGSI-LDES splits the data into cacheable Web documents. Such a document contains a fragment of the context broker's data and is linked with TREE hypermedia links towards other fragments.

Requirements

• NGSI-LD temporal interface
• Support for count parameter

Get started

Rename .env.example to .env and fill in the variables. Note that NGSI_TYPES requires a list of types. You need to surround the string with double quotes when running locally. When using Docker, remove the double quotes.

Also add the correct baseUrl and port to bin/server.js

git clone git@github.com:TREEcg/ngsi-ldes.git
cd ngsi-ldes
yarn start

Or with Docker:

docker build -t ngsi-ldes -f Dockerfile-ngsi-ldes .
docker run --env-file .env -p 3001:3001 -d ngsi-ldes

Go to http://localhost:3001 to have a DCAT overview of LDESs.

Example setup with Scorpio

You can test a full setup with Scorpio using Docker compose:

docker build -t reverseproxy -f Dockerfile-nginx-alpine .
docker-compose -f scorpio-aaio.yml up

Dockerfile-nginx-alpine generates a reverse proxy that will be used on top of the NGSI-LD broker and NGSI-LDES allowing HTTP caching. Note that the environment variables are configurable inside this yaml file. Go to http://localhost:8081 to access the NGSI-LDES DCAT overview through the reverse proxy.

Acknowledgements

This work was started thanks to the ODALA project, and further developer during the CEF GreenMov project.