interceptor

README

interceptor

Simple HTTP request interceptor

The concept

• define the interceptor to use for every outgoing request
• create a request
• provide an HTTP client
• send the request with interceptor

Examples

• retry while destination service is unavailable

interceptor.New(
    interceptor.Retry(serviceConfig.Client.MaxRetries),
    interceptor.WithInterval(time.Duration(serviceConfig.Client.RetryInterval)),
    interceptor.WhileFails(func(r *http.Response) error {
        if r.StatusCode == 503 {
            return errors.ServiceUnavailable("service is unavailable")
        }

        return nil
    }),
).Then(http.DefaultClient).Do(req)

• throttle

var (
    ticker = time.NewTicker(duration)
    icp = interceptor.New(interceptor.Throttle(ticker.C)).Then(http.DefaultClient)
)

icp.Do(req)
icp.Do(req)
. . .
icp.Do(req)

Documentation

Index

• type Doer
• type DoerFunc
  • func (fn DoerFunc) Do(req *http.Request) (*http.Response, error)
• type Interceptor
  • func Log(debugfFunc, errorfFunc func(string, ...interface{})) Interceptor
  • func New(interceptors ...Interceptor) Interceptor
  • func Retry(tries int) Interceptor
  • func Throttle(tick <-chan time.Time) Interceptor
  • func UntilStatusCodeIs(status int) Interceptor
  • func WhileFails(checkFunc func(*http.Response) error) Interceptor
  • func WithInterval(duration time.Duration) Interceptor
  • func (icp Interceptor) Then(doer Doer) Doer
  • func (icp Interceptor) Use(interceptors ...Interceptor) Interceptor

Types

type Doer

type Doer interface {
	Do(req *http.Request) (*http.Response, error)
}

type DoerFunc

type DoerFunc func(req *http.Request) (*http.Response, error)

func (DoerFunc) Do

func (fn DoerFunc) Do(req *http.Request) (*http.Response, error)

type Interceptor

type Interceptor func(next Doer) Doer

func Log

func Log(
	debugfFunc, errorfFunc func(string, ...interface{}),
) Interceptor

func New

func New(interceptors ...Interceptor) Interceptor

func Retry

func Retry(tries int) Interceptor

Retry request interceptor, call `Retry(0)` means make a single call with no retry.

func Throttle

func Throttle(tick <-chan time.Time) Interceptor

Throttle provides an interceptor that delays client request waiting for a value from an input channel. Use `time.NewTicker(duration).C` or `time.Tick(duration)` as an input parameter.

Example:

var (
	ticker = time.NewTicker(duration)
	icp = interceptor.New(interceptor.Throttle(ticker.C)).Then(http.DefaultClient)
)

icp.Do(req)
icp.Do(req)
. . .
icp.Do(req)

func UntilStatusCodeIs

func UntilStatusCodeIs(status int) Interceptor

UntilStatusCodeIs returns an error until specified response status code is received.

func WhileFails

func WhileFails(checkFunc func(*http.Response) error) Interceptor

WhileFails is one of the configurable parts of retry strategy. Specify the function to check the response and return descriptive error message if needed.

func WithInterval

func WithInterval(duration time.Duration) Interceptor

func (Interceptor) Then

func (icp Interceptor) Then(doer Doer) Doer

func (Interceptor) Use

func (icp Interceptor) Use(interceptors ...Interceptor) Interceptor