Circuit breaker around flaky dependencies

                  package deps

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

  "github.com/sony/gobreaker"
)

type Client struct {
  http *http.Client
  cb   *gobreaker.CircuitBreaker
}

func NewClient(httpClient *http.Client) *Client {
  st := gobreaker.Settings{
    Name:        "billing-api",
    MaxRequests: 5,
    Interval:    30 * time.Second,
    Timeout:     10 * time.Second,
    ReadyToTrip: func(c gobreaker.Counts) bool { return c.ConsecutiveFailures >= 5 },
  }
  return &Client{http: httpClient, cb: gobreaker.NewCircuitBreaker(st)}
}

func (c *Client) Do(ctx context.Context, req *http.Request) (*http.Response, error) {
  v, err := c.cb.Execute(func() (any, error) {
    return c.http.Do(req.WithContext(ctx))
  })
  if err != nil {
    return nil, err
  }
  return v.(*http.Response), nil
}