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igrac_api and istSOS

GGIS exposes sensor observation data through the OGC SOS 1.0.0 standard. This is implemented as a two-layer stack: the igrac_api Django app acts as an authenticated gateway, and istSOS 2 (running as a separate container) handles the actual SOS protocol.

istSOS 2 (submodule)

Source: github.com/meomancer/istsos2 — branch igrac

istSOS is an open-source Python implementation of the OGC Sensor Observation Service. GGIS uses a fork pinned to the igrac branch that contains IGRAC-specific patches.

istSOS runs as its own Docker container (istsos service) with pre-configured service definitions located in deployment/istsos/services/. It is not exposed directly to the public — all traffic is routed through igrac_api.

Supported SOS operations

Operation Description
GetCapabilities Returns service metadata and available offerings
DescribeSensor Returns SensorML description for a given procedure
GetObservation Returns time-series measurements for a procedure
InsertObservation Inserts new observation records

igrac_api Django App

igrac_api is the Django app that sits in front of istSOS. Its responsibilities:

  • Authentication — validates the api-key query parameter on every SOS request before forwarding to istSOS. Unauthenticated requests are rejected.
  • Request proxying — forwards valid SOS requests to the istSOS container and returns the XML response unchanged.
  • Download API — additional REST endpoints for bulk data downloads that do not go through istSOS (these return data directly from the gwml2 database).
  • Celery tasks — background jobs for generating download files asynchronously.

Example API calls

GetCapabilities 

GET /istsos?service=SOS&request=GetCapabilities&api-key=<api-key>

DescribeSensor 

GET /istsos?service=SOS&version=1.0.0&request=DescribeSensor
    &procedure=<procedure-id>
    &outputFormat=text/xml;subtype="sensorML/1.0.1"
    &api-key=<api-key>

Directory Structure

igrac_api/
├── api/          # DRF viewsets — SOS proxy and download endpoints
├── serializer/   # DRF serializers
├── tasks/        # Celery tasks (async download generation)
├── forms/        # API key and filter forms
├── models/       # API key model
├── migrations/   # Database migrations
└── urls.py       # URL routing

deployment/istsos/
├── Dockerfile    # istSOS container image
└── services/     # Pre-configured istSOS service definitions