resilience

export interface RetryOptions {
  retries: number;
  baseMs: number;
  maxMs: number;
  signal?: AbortSignal;
  onRetry?: (attempt: number, delay: number, err: unknown) => void;

import React from "react";

type FallbackProps = {
  error: Error;
  reset: () => void;
};

class FeatureFlag < ApplicationRecord
  validates :key, presence: true, uniqueness: true
  validates :percentage, inclusion: { in: 0..100 }

  after_commit :expire_cache

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

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;

import { ApplicationConfig } from '@angular/core';
import {
  provideHttpClient,
  withInterceptors,
} from '@angular/common/http';
import { retryInterceptor } from './retry.interceptor';

package com.example.fx.config;

import com.github.benmanes.caffeine.cache.Caffeine;
import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cache.caffeine.CaffeineCacheManager;

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;

public class ProductAggregator implements AutoCloseable {

    private final RemoteServices services;
    private final ExecutorService pool = Executors.newFixedThreadPool(8);

    public ProductAggregator(RemoteServices services) {

module Retryable
  module_function

  def with_retries(tries: 3, base: 0.3, cap: 5.0, on: [StandardError])
    attempt = 0
    begin

module ConnectionHealth
  extend ActiveSupport::Concern

  def with_fresh_connection
    conn = ActiveRecord::Base.connection
    conn.verify! # pings and reconnects if the socket is dead