Function fetch_weather

evi/evi-python-function-calling/main.py:170–275

Fetch the weather forecast for all periods for a given location. This asynchronous function retrieves the weather forecast for the specified location using the Geocoding API to obtain geographic coordinates and the Weather.gov API to fetch the weather forecast. It converts the temperatu

(location: str, format: str)

        print(f"Error: {error}")

async def fetch_weather(location: str, format: str) -> str:
    """Fetch the weather forecast for all periods for a given location.

    This asynchronous function retrieves the weather forecast for the specified
    location using the Geocoding API to obtain geographic coordinates and the
    Weather.gov API to fetch the weather forecast. It converts the temperatures
    of all forecast periods into the desired unit and returns the forecast data
    as a JSON-formatted string.

    Args:
        location (str): The name of the location for which to fetch the weather forecast.
            This can be any location recognized by the Geocoding API (e.g., "New York City").
        format (str): The temperature unit for the output. Accepts 'fahrenheit' or 'celsius'.

    Returns:
        str: The JSON-formatted string of all forecast periods with temperatures
             converted to the specified unit.

    Raises:
        Returns an error message string prefixed with "ERROR:" if any step fails, such as
        missing API keys, network errors, or data extraction issues.
    """
    # Retrieve the Geocoding API key from environment variables
    GEOCODING_API_KEY = os.getenv("GEOCODING_API_KEY")
    if not GEOCODING_API_KEY:
        return "ERROR: Geocoding API key is not set."

    # Construct the URL for the Geocoding API request
    location_api_url = f"https://geocode.maps.co/search?q={location}&api_key={GEOCODING_API_KEY}"

    # Create an HTTP client that automatically follows redirects
    async with httpx.AsyncClient(follow_redirects=True) as client:
        try:
            # Step 1: Fetch location data
            location_response = await client.get(location_api_url)
            location_response.raise_for_status()
            location_data = location_response.json()
        except httpx.HTTPError as e:
            return f"ERROR: Failed to fetch location data. {str(e)}"

        if not location_data:
            return "ERROR: No location data found."

        try:
            # Extract latitude and longitude from the location data
            lat = location_data[0]['lat']
            lon = location_data[0]['lon']
        except (IndexError, KeyError):
            return "ERROR: Unable to extract latitude and longitude."

        # Construct the URL for the Weather.gov API points endpoint
        point_metadata_endpoint = f"https://api.weather.gov/points/{float(lat):.4f},{float(lon):.4f}"

        try:
            # Step 2: Fetch point metadata
            point_metadata_response = await client.get(point_metadata_endpoint)
            point_metadata_response.raise_for_status()
            point_metadata = point_metadata_response.json()