Authentication Patterns

Overview

Common authentication patterns for integrating with external services. Provides consistent approaches to credential management, verification, and error handling.

When To Use

• Integrating with external APIs
• Need credential verification
• Managing multiple auth methods
• Handling auth failures gracefully

When NOT To Use

• Project doesn't use the leyline infrastructure patterns
• Simple scripts without service architecture needs

Authentication Methods

Method	Best For	Environment Variable
API Key	Simple integrations	{SERVICE}_API_KEY
OAuth	User-authenticated	Browser-based flow
Token	Session-based	{SERVICE}_TOKEN
None	Public APIs	N/A

Quick Start

Verify Authentication

from leyline.auth import verify_auth, AuthMethod

# API Key verification
status = verify_auth(
    service="gemini", method=AuthMethod.API_KEY, env_var="GEMINI_API_KEY"
)

if not status.authenticated:
    print(f"Auth failed: {status.message}")
    print(f"Action: {status.suggested_action}")

Verification: Run the command with --help flag to verify availability.

Smoke Test

def verify_with_smoke_test(service: str) -> bool:
    """Verify auth with simple request."""
    result = execute_simple_request(service, "ping")
    return result.success

Verification: Run pytest -v to verify tests pass.

Standard Flow

Step 1: Check Environment

def check_credentials(service: str, env_var: str) -> bool:
    value = os.getenv(env_var)
    if not value:
        print(f"Missing {env_var}")
        return False
    return True

Verification: Run the command with --help flag to verify availability.

Step 2: Verify with Service

def verify_with_service(service: str) -> AuthStatus:
    result = subprocess.run([service, "auth", "status"], capture_output=True)
    return AuthStatus(
        authenticated=(result.returncode == 0), message=result.stdout.decode()
    )

Verification: Run the command with --help flag to verify availability.

Step 3: Handle Failures

def handle_auth_failure(service: str, method: AuthMethod) -> str:
    actions = {
        AuthMethod.API_KEY: f"Set {service.upper()}_API_KEY environment variable",
        AuthMethod.OAUTH: f"Run '{service} auth login' for browser auth",
        AuthMethod.TOKEN: f"Refresh token with '{service} token refresh'",
    }
    return actions[method]

Verification: Run the command with --help flag to verify availability.

Integration Pattern

# In your skill's frontmatter
dependencies: [leyline:authentication-patterns]

Verification: Run the command with --help flag to verify availability.

Interactive Authentication (Shell)

For workflows requiring interactive authentication with token caching and session management:

# Source the interactive auth script
source plugins/leyline/scripts/interactive_auth.sh

# Ensure authentication before proceeding
ensure_auth github || exit 1
ensure_auth gitlab || exit 1
ensure_auth aws || exit 1

# Continue with authenticated operations
gh pr view 123
glab issue list
aws s3 ls

Features:

• ✅ Interactive OAuth flows for GitHub, GitLab, AWS, and more
• ✅ Token caching (5-minute TTL)
• ✅ Session persistence (24-hour TTL)
• ✅ CI/CD compatible (auto-detects non-interactive environments)
• ✅ Multi-service support

See modules/interactive-auth.md for complete documentation.

Detailed Resources

• Auth Methods: See modules/auth-methods.md for method details
• Verification: See modules/verification-patterns.md for testing patterns
• Interactive: See modules/interactive-auth.md for shell-based auth flows

Exit Criteria

• Credentials verified or clear failure message
• Suggested action for auth failures
• Smoke test confirms working auth