How to Set Up Authentication for FastFuels SDK

This guide shows you how to configure API authentication for the FastFuels SDK in different environments.

How to Configure Authentication Using Environment Variables

For production environments, set your API key as an environment variable:

# Linux/MacOS
export FASTFUELS_API_KEY="your-api-key-here"

# Windows (Command Prompt)
set FASTFUELS_API_KEY=your-api-key-here

# Windows (PowerShell)
$env:FASTFUELS_API_KEY="your-api-key-here"

Then import and use the SDK - it will automatically use the environment variable:

from fastfuels_sdk import api
from fastfuels_sdk.domains import Domain

# SDK automatically uses FASTFUELS_API_KEY environment variable
domain = Domain.from_id("your-domain-id")

How to Configure Authentication Programmatically

For development or testing environments, set the API key in your code:

from fastfuels_sdk import api

# Configure the API key
api.set_api_key("your-api-key-here")

# SDK will now use this key for all operations

How to Handle Missing Authentication

Add error handling for cases where authentication isn't properly configured:

from fastfuels_sdk import api
from fastfuels_sdk.client_library.exceptions import UnauthorizedException

try:
    # Will raise UnauthorizedException if no API key is configured
    from fastfuels_sdk.domains import Domain
    domain = Domain.from_id("your-domain-id")
except UnauthorizedException as e:
    print(f"Authentication error: {e}")
    # Add your error handling logic here

How to Update Authentication at Runtime

If you need to switch API keys during execution:

from fastfuels_sdk import api

def switch_auth_key(new_key: str) -> None:
    """Update authentication to use a new API key."""
    api.set_api_key(new_key)

# Usage
switch_auth_key("new-api-key")

Remember: The API client is maintained as a singleton, so setting a new API key affects all subsequent operations in your application.