import CircuitBreaker from 'opossum';

function asyncFunctionThatCouldFail(x, y) {
    return new Promise((resolve, reject) => {
        // Do something, maybe on the network or a disk
    });
}

const options = {
    timeout: 3000, // If our function takes longer than 3 seconds, trigger a failure
    errorThresholdPercentage: 50, // When 50% of requests fail, trip the circuit
    resetTimeout: 30000, // After 30 seconds, try again.
};
const breaker = new CircuitBreaker(asyncFunctionThatCouldFail, options);

breaker.fire(x, y).then(console.log).catch(console.error);

import CircuitBreaker from 'opossum';

function asyncFunctionThatCouldFail(x, y) {
    return new Promise((resolve, reject) => {
        // Do something, maybe on the network or a disk
    });
}

const options = {
    timeout: 3000, // If our function takes longer than 3 seconds, trigger a failure
    errorThresholdPercentage: 50, // When 50% of requests fail, trip the circuit
    resetTimeout: 30000, // After 30 seconds, try again.
};
const breaker = new CircuitBreaker(asyncFunctionThatCouldFail, options)
    .fallback(() => 'do something else');    

breaker.fire(x, y).then(console.log).catch(console.error);

    # Calls category
    getCategory(categoryUrl: $categoryUrl) {
      id
      howto
      # Calls content service
      ... on ContentCategory {
        content {
          id
          title
          body
        }
      }
      # Calls product service
      ... on ProductCategory {
        productCollection {
          items {
            ... on Product {
              ...productForList
            }
            # Calls estimated delivery service
            ... on BonusSet {
              estimatedDeliveries {
                ...productEstimatedDeliveryFragment
              }
            }
            # Calls banners service
            ... on SectionBannerSlideImage {
              ...sectionBannerSlide
            }
          }
        }
      }
    }
  

// 👉 every resolver has unique name - Query:category, Category:productCollection
const resolvers = {
    Query: {
        category: resolveCategory,
    },
    Category: {
        productCollection: resolveProductCollection,
    },
};

// 🌍 global configuration of specific resolvers
export const resolverConfig: Map<string, ResolverConfig> = new Map<string, ResolverConfig>()
    .set('Query:category', { timeout: 3000 })
    .set('Category:productCollection', { timeout: 3000, fallback: () => [] });

// 👷 Usage of high order function. Resolver is wrapped by circuit breaker
const resolversWithCircuitBreakers = mapResolvers(
    resolvers,
    // 
    ({ resolver, name }: CreateResolverInput): IFieldResolver<unknown, unknown, unknown> => {
        const { ...breakerDefaultConfig } = resolverConfig.get(name) ?? {};
        const config = { name, ...breakerDefaultConfig };
        const breaker = createCircuitBreaker(config, resolver);

        return async (...params: ResolverParams): Promise<unknown> => breaker.fire(...params);
    },
);