Table of Contents

• Overview
• When to Use
• Core Concepts
• Service Configuration
• Execution Result
• Quick Start
• Register Services
• Execute via Service
• Health Checks
• Service Selection
• Auto-Selection
• Failover Pattern
• Integration Pattern
• Detailed Resources
• Exit Criteria

Service Registry

Overview

A registry pattern for managing connections to external services. Handles configuration, health checking, and execution across multiple service integrations.

When to Use

• Managing multiple external services.
• Need consistent execution interface.
• Want health monitoring across services.
• Building service failover logic.

Core Concepts

Service Configuration

@dataclass
class ServiceConfig:
    name: str
    command: str
    auth_method: str  # "api_key", "oauth", "token"
    auth_env_var: str
    quota_limits: dict
    models: list[str] = field(default_factory=list)

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

Execution Result

@dataclass
class ExecutionResult:
    success: bool
    stdout: str
    stderr: str
    exit_code: int
    duration: float
    tokens_used: int

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

Quick Start

Register Services

from leyline.service_registry import ServiceRegistry

registry = ServiceRegistry()

registry.register("gemini", ServiceConfig(
    name="gemini",
    command="gemini",
    auth_method="api_key",
    auth_env_var="GEMINI_API_KEY",
    quota_limits={"rpm": 60, "daily": 1000}
))

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

Execute via Service

result = registry.execute(
    service="gemini",
    prompt="Analyze this code",
    files=["src/main.py"],
    model="gemini-2.5-pro"
)

if result.success:
    print(result.stdout)

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

Health Checks

# Check single service
status = registry.health_check("gemini")

# Check all services
all_status = registry.health_check_all()
for service, healthy in all_status.items():
    print(f"{service}: {'OK' if healthy else 'FAILED'}")

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

Service Selection

Auto-Selection

# Select best service for task
service = registry.select_service(
    requirements={
        "large_context": True,
        "fast_response": False
    }
)

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

Failover Pattern

def execute_with_failover(prompt: str, files: list) -> ExecutionResult:
    for service in registry.get_healthy_services():
        result = registry.execute(service, prompt, files)
        if result.success:
            return result
    raise AllServicesFailedError()

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

Integration Pattern

# In your skill's frontmatter
dependencies: [leyline:service-registry]

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

Detailed Resources

• Service Config: See modules/service-config.md for configuration options.
• Execution Patterns: See modules/execution-patterns.md for advanced usage.

Exit Criteria

• Services registered with configuration.
• Health checks passing.
• Execution results properly handled.

Troubleshooting

Common Issues

Command not found Ensure all dependencies are installed and in PATH

Permission errors Check file permissions and run with appropriate privileges

Unexpected behavior Enable verbose logging with --verbose flag