circuit-breaker-pattern

SKILL.md

Circuit Breaker Pattern

Table of Contents

Overview

When to Use

Quick Start

Reference Guides

Best Practices

Overview

Implement circuit breaker patterns to prevent cascading failures and provide graceful degradation when dependencies fail.

When to Use

External API calls

Microservices communication

Database connections

Third-party service integrations

Preventing cascading failures

Implementing fallback mechanisms

Rate limiting protection

Timeout handling

Quick Start

Minimal working example:

enum CircuitState {
  CLOSED = "CLOSED",
  OPEN = "OPEN",
  HALF_OPEN = "HALF_OPEN",
}

interface CircuitBreakerConfig {
  failureThreshold: number;
  successThreshold: number;
  timeout: number;
  resetTimeout: number;
}

interface CircuitBreakerStats {
  failures: number;
  successes: number;
  consecutiveFailures: number;
  consecutiveSuccesses: number;
  lastFailureTime?: number;
}

class CircuitBreaker {
  private state: CircuitState = CircuitState.CLOSED;
  private stats: CircuitBreakerStats = {
    failures: 0,
// ... (see reference guides for full implementation)

Reference Guides

Detailed implementations in the references/ directory:

Guide
Contents

TypeScript Circuit Breaker
TypeScript Circuit Breaker

Circuit Breaker with Monitoring
Circuit Breaker with Monitoring

Opossum-Style Circuit Breaker (Node.js)
Opossum-Style Circuit Breaker (Node.js)

Python Circuit Breaker
Python Circuit Breaker

Resilience4j-Style (Java)
Resilience4j-Style (Java)

Best Practices

✅ DO

Use appropriate thresholds for your use case

Implement fallback mechanisms

Monitor circuit breaker states

Set reasonable timeouts

Use exponential backoff

Log state transitions

Alert on frequent trips

Test circuit breaker behavior

Use per-dependency breakers

Implement health checks

❌ DON'T

Use same breaker for all dependencies

Set unrealistic thresholds

Skip fallback implementation

Ignore open circuit breakers

Use overly aggressive reset timeouts

Forget to monitor

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