Model Metadata

Overview

The Model Metadata API provides endpoints to retrieve information about trained demand prediction models, including version, performance metrics, training timestamp, and dataset statistics.

Base URL

https://your-domain.com/v1/ml

Get Latest Model

GET /v1/ml/models/latest

Retrieves metadata for the currently active prediction model. Authentication: Required (JWT or internal service key) Authorization: Configurable permissions (default: requires valid token)

Response

version

string

Model version identifier

trained_at

string

Training completion timestamp (ISO 8601)

metrics

object

Model performance metrics

metrics.mae

number

Mean Absolute Error

metrics.rmse

number

Root Mean Square Error

metrics.mape

number

Mean Absolute Percentage Error

metrics.r2

number

R-squared coefficient

train_samples

integer

Number of training samples

test_samples

integer

Number of test samples

total_samples

integer

Total number of samples in dataset

algorithm

string

Machine learning algorithm used (e.g., “Prophet”, “ARIMA”, “XGBoost”)

features

array

List of feature names used in the model

segments_covered

integer

Number of vehicle segments with sufficient data for predictions

{
  "version": "v1.3.0-20260306",
  "trained_at": "2026-03-06T14:35:22Z",
  "metrics": {
    "mae": 1.32,
    "rmse": 1.95,
    "mape": 0.14,
    "r2": 0.87
  },
  "train_samples": 8540,
  "test_samples": 2135,
  "total_samples": 10675,
  "algorithm": "Prophet",
  "features": [
    "vehicle_type",
    "brand",
    "model",
    "line",
    "month",
    "year",
    "seasonality",
    "trend",
    "lag_1",
    "lag_3",
    "rolling_mean_3"
  ],
  "segments_covered": 245
}

Status Codes

200 OK - Model metadata retrieved successfully
401 Unauthorized - Missing or invalid authentication
403 Forbidden - Insufficient permissions
404 Not Found - No trained model available

Example

curl -X GET https://your-domain.com/v1/ml/models/latest \
  -H "Authorization: Bearer YOUR_TOKEN"

No Model Available Response

If no model has been trained yet, the API returns:

{
  "detail": "No hay modelos disponibles"
}

Status Code: 200 OK (with informational message)

Model Metadata Fields

Version

Unique identifier for the model following semantic versioning with timestamp:

Format: v{major}.{minor}.{patch}-{YYYYMMDD}
Example: v1.3.0-20260306
Purpose: Track model lineage and enable rollback

Trained At

ISO 8601 timestamp indicating when training completed:

Format: YYYY-MM-DDTHH:MM:SSZ
Timezone: UTC
Example: 2026-03-06T14:35:22Z

Metrics

Performance metrics calculated on the test set:

Mean Absolute Error (MAE)

Description: Average absolute prediction error
Units: Number of vehicles
Interpretation: Lower is better
Good value: < 2.0

Root Mean Square Error (RMSE)

Description: Standard deviation of prediction errors
Units: Number of vehicles
Interpretation: Lower is better, penalizes large errors
Good value: < 3.0

Mean Absolute Percentage Error (MAPE)

Description: Average percentage error
Units: Decimal (0-1)
Interpretation: Lower is better
Good value: < 0.20 (20%)

R-squared (R²)

Description: Proportion of variance explained
Range: 0-1 (can be negative)
Interpretation: Higher is better
Good value: > 0.75

Dataset Statistics

Train Samples

Number of data points used for training the model.

Test Samples

Number of data points held out for validation.

Total Samples

Sum of training and test samples. Typical split: 80% train, 20% test

Algorithm

The machine learning or statistical algorithm used:

Prophet - Facebook’s time series forecasting library
ARIMA - Auto-Regressive Integrated Moving Average
XGBoost - Gradient boosting for regression
LSTM - Long Short-Term Memory neural network

Features

List of input variables used by the model: Common features:

vehicle_type - CAR or MOTORCYCLE
brand - Manufacturer
model - Model year
line - Vehicle line/variant
month - Month of year (seasonality)
year - Year (trend)
lag_1, lag_3 - Previous months’ sales
rolling_mean_3 - 3-month moving average

Segments Covered

Number of unique vehicle segments (brand/model/line combinations) with sufficient historical data for predictions.

Higher is better - More coverage means predictions available for more vehicles
Typical range: 100-500 segments

Use Cases

Model Monitoring Dashboard

Display current model status:

fetch('https://your-domain.com/v1/ml/models/latest', {
  headers: { 'Authorization': `Bearer ${token}` }
})
  .then(res => res.json())
  .then(model => {
    console.log(`Current model: ${model.version}`);
    console.log(`Accuracy (MAE): ${model.metrics.mae}`);
    console.log(`Trained: ${new Date(model.trained_at).toLocaleString()}`);
  });

Model Comparison

Compare metrics before and after retraining to assess improvement:

import requests

# Get current model
current = requests.get(
    "https://your-domain.com/v1/ml/models/latest",
    headers={"Authorization": f"Bearer {token}"}
).json()

print(f"Current MAE: {current['metrics']['mae']}")
print(f"Current R²: {current['metrics']['r2']}")

# Retrain
retrain_response = requests.post(
    "https://your-domain.com/v1/ml/retrain",
    headers={"Authorization": f"Bearer {token}"},
    json={}
)

new_model = retrain_response.json()
print(f"New MAE: {new_model['metrics']['mae']}")
print(f"New R²: {new_model['metrics']['r2']}")

# Compare
mae_improvement = current['metrics']['mae'] - new_model['metrics']['mae']
print(f"MAE improvement: {mae_improvement:.2f}")

Health Check

Verify that a model is available before making predictions:

def is_model_available():
    response = requests.get(
        "https://your-domain.com/v1/ml/models/latest",
        headers={"Authorization": f"Bearer {token}"}
    )
    
    if response.status_code != 200:
        return False
    
    data = response.json()
    return "version" in data

if is_model_available():
    # Make predictions
    predict(...)
else:
    print("No model available. Please train a model first.")

Model Staleness Detection

Check if the model needs retraining:

from datetime import datetime, timedelta

def is_model_stale(max_age_days=30):
    response = requests.get(
        "https://your-domain.com/v1/ml/models/latest",
        headers={"Authorization": f"Bearer {token}"}
    ).json()
    
    if "detail" in response:  # No model
        return True
    
    trained_at = datetime.fromisoformat(
        response["trained_at"].replace("Z", "+00:00")
    )
    age = datetime.now(trained_at.tzinfo) - trained_at
    
    return age.days > max_age_days

if is_model_stale():
    print("Model is stale. Triggering retraining...")
    requests.post(
        "https://your-domain.com/v1/ml/retrain",
        headers={"Authorization": f"Bearer {token}"},
        json={}
    )

Model Quality Assessment

def assess_model_quality(metrics):
    mae = metrics['mae']
    rmse = metrics['rmse']
    mape = metrics['mape']
    r2 = metrics['r2']
    
    if mae < 1.0 and mape < 0.10 and r2 > 0.90:
        return "Excellent"
    elif mae < 2.0 and mape < 0.20 and r2 > 0.75:
        return "Good"
    elif mae < 3.0 and mape < 0.30 and r2 > 0.60:
        return "Fair"
    else:
        return "Poor"

model = requests.get(
    "https://your-domain.com/v1/ml/models/latest",
    headers={"Authorization": f"Bearer {token}"}
).json()

quality = assess_model_quality(model['metrics'])
print(f"Model quality: {quality}")

if quality == "Poor":
    print("Consider investigating data quality or algorithm choice")

API Documentation Link

For interactive API documentation, visit:

https://your-domain.com/docs

The ML service uses FastAPI and provides automatic OpenAPI documentation.

Error Responses

401 Unauthorized

{
  "detail": "Not authenticated"
}

403 Forbidden

{
  "detail": "User does not have required permission: ml:models"
}

404 Not Found (No Model)

{
  "detail": "No hay modelos disponibles"
}

Health Check Endpoint

The ML service also provides a health check endpoint:

GET /actuator/health

Alternative: /health Authentication: None (public endpoint)

Response

{
  "status": "healthy",
  "service": "sgivu-ml",
  "version": "1.0.0",
  "model_available": true
}

Example

curl -X GET https://your-domain.com/health

Integration with Gateway

In production, ML endpoints are typically accessed through the API gateway:

Gateway: https://your-domain.com/v1/ml/**
  → Routes to: http://sgivu-ml:8000/v1/ml/**

The gateway handles:

JWT token validation
Request routing
Rate limiting
Logging and monitoring

Authentication

User Management

Vehicle Management

Client Management

Purchase & Sales

Machine Learning

​Overview

​Base URL

​Get Latest Model

​Response

​Status Codes

​Example

​No Model Available Response

​Model Metadata Fields

​Version

​Trained At

​Metrics

​Mean Absolute Error (MAE)

​Root Mean Square Error (RMSE)

​Mean Absolute Percentage Error (MAPE)

​R-squared (R²)

​Dataset Statistics

​Train Samples

​Test Samples

​Total Samples

​Algorithm

​Features

​Segments Covered

​Use Cases

​Model Monitoring Dashboard

​Model Comparison

​Health Check

​Model Staleness Detection

​Model Quality Assessment

​API Documentation Link

​Error Responses

​401 Unauthorized

​403 Forbidden

​404 Not Found (No Model)

​Health Check Endpoint

​Response

​Example

​Integration with Gateway

Overview

Base URL

Get Latest Model

Response

Status Codes

Example

No Model Available Response

Model Metadata Fields

Version

Trained At

Metrics

Mean Absolute Error (MAE)

Root Mean Square Error (RMSE)

Mean Absolute Percentage Error (MAPE)

R-squared (R²)

Dataset Statistics

Train Samples

Test Samples

Total Samples

Algorithm

Features

Segments Covered

Use Cases

Model Monitoring Dashboard

Model Comparison

Health Check

Model Staleness Detection

Model Quality Assessment

API Documentation Link

Error Responses

401 Unauthorized

403 Forbidden

404 Not Found (No Model)

Health Check Endpoint

Response

Example

Integration with Gateway