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API Endpoints (Python Inference Service)

Traffic Inference

POST /predict_action

Predict the next optimal green phase for a specific junction.

Request Body: 

{
  "junction_id": "300839359",
  "obs_data": [0.0, 1.0, 1.0, 0.12, 0.33, 0.41, 0.22, 0.55]
}

Response (200): 

{
  "junction_id": "300839359",
  "action": 1,
  "confidence": 0.87
}

Parameters:

  • junction_id (string, required): One of the 5 known junction IDs
  • obs_data (array of floats, required): Local observation vector
  • Smaller observations are automatically zero-padded to 19 floats
  • Maximum size: 19 floats

Errors:

  • 404: Unknown junction ID
  • 400: Observation size exceeds 19 floats
  • 503: Model not loaded

Hidden State Management:

  • Each call updates and persists the GRU hidden state for that junction
  • Call POST /reset_hidden at the start of each new simulation run

POST /reset_hidden

Reset GRU hidden states for all junctions. Call at the start of each new simulation run.

Request Body: (empty)

Response (200): 

{
  "status": "ok",
  "message": "Hidden states reset for all junctions"
}

System Health & Information

GET /health

Service health check.

Response (200): 

{
  "status": "healthy",
  "model_loaded": true,
  "junctions": [
    "joinedS_265580996_300839357",
    "300839359",
    "265580972",
    "1270712555",
    "8541180897"
  ]
}

Status Values:

  • healthy: Model loaded and ready
  • no_model: Service running but model not loaded
  • unhealthy: Service error

GET /model_info

Get detailed information about the loaded MAPPO model.

Response (200): 

{
  "architecture": "RNNAgent (GRU)",
  "input_shape": 24,
  "hidden_dim": 128,
  "n_actions": 4,
  "n_agents": 5,
  "obs_agent_id": true,
  "junctions": {
    "joinedS_265580996_300839357": {
      "agent_index": 0,
      "avail_actions": [1, 1, 1, 1],
      "valid_actions": 4
    },
    "300839359": {
      "agent_index": 1,
      "avail_actions": [1, 1, 0, 0],
      "valid_actions": 2
    }
  }
}

GET /

HTML landing page with links to documentation, status checks, and the API Gateway.

Response: HTML page with navigation links

GET /docs

FastAPI Swagger UI (auto-generated from OpenAPI schema).

Response: Interactive API documentation