circuit-breaker

require "faraday"
require "faraday/retry"

module Http
  class RetryableError < StandardError; end
  class CircuitOpenError < StandardError; end

class CircuitBreaker
  class CircuitOpenError < StandardError; end

  INCREMENT = <<~LUA.freeze
    local n = redis.call('INCR', KEYS[1])
    if n == 1 then redis.call('EXPIRE', KEYS[1], ARGV[1]) end

package deps

import (
  "context"
  "net/http"
  "time"

export type CircuitState = "closed" | "open" | "half-open";

export interface CircuitBreakerOptions {
  failureThreshold: number;
  resetTimeout: number; // ms to wait in "open" before probing
  onStateChange?: (from: CircuitState, to: CircuitState) => void;

package com.example.rates.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.retry.annotation.EnableRetry;
import org.springframework.web.client.RestTemplate;

package com.example.demo.service;

import io.github.resilience4j.circuitbreaker.annotation.CircuitBreaker;
import io.github.resilience4j.ratelimiter.annotation.RateLimiter;
import io.github.resilience4j.retry.annotation.Retry;
import io.github.resilience4j.bulkhead.annotation.Bulkhead;

class CircuitBreaker
  class CircuitOpenError < StandardError; end

  def initialize(name, redis: Redis.current, failure_threshold: 5, failure_window: 60, cooldown: 30)
    @key = "circuit:#{name}"
    @redis = redis