# README
http_retry
import "github.com/improbable-eng/go-httpwares/retry"
Overview
http_retry is a HTTP client-side Tripperware that allows you to retry requests that are marked as idempotent and safe.
This logic works for requests considered safe and idempotent (configurable) and ones that have no body, or have Request.GetBody either automatically implemented (byte.Buffer, string.Buffer) or specified manually. By default all GET, HEAD and OPTIONS requests are considered idempotent and safe.
The implementation allow retries after client-side errors or returned error codes (by default 5**) according to configurable backoff policies (linear backoff by default). Additionally, requests can be hedged. Hedging works by sending additional requests without waiting for a previous one to return.
Imported Packages
Index
- func DefaultResponseDiscarder(resp *http.Response) bool
- func DefaultRetriableDecider(req *http.Request) bool
- func Enable(req *http.Request) *http.Request
- func EnableContext(ctx context.Context) context.Context
- func Tripperware(opts ...Option) httpwares.Tripperware
- type BackoffFunc
- type Option
- type RequestRetryDeciderFunc
- type ResponseDiscarderFunc
Package files
backoff.go context.go doc.go get_body_go18.go options.go tripperware.go
func DefaultResponseDiscarder
func DefaultResponseDiscarder(resp *http.Response) bool
DefaultResponseDiscarder is the default implementation that discards responses in order to try again.
It is fairly conservative and rejects (and thus retries) responses with 500, 503 and 504 status codes. See https://en.wikipedia.org/wiki/List_of_HTTP_status_codes#5xx_Server_error
func DefaultRetriableDecider
func DefaultRetriableDecider(req *http.Request) bool
DefaultRetriableDecider is the default implementation that retries only indempotent and safe requests (GET, OPTION, HEAD).
It is fairly conservative and heeds the of http://restcookbook.com/HTTP%20Methods/idempotency.
func Enable
func Enable(req *http.Request) *http.Request
Enable turns on the retry logic for a given request, regardless of what the retry decider says.
Please make sure you do not pass around this request's context.
func EnableContext
func EnableContext(ctx context.Context) context.Context
Enable turns on the retry logic for a given request's context, regardless of what the retry decider says.
Please make sure you do not pass around this request's context.
func Tripperware
func Tripperware(opts ...Option) httpwares.Tripperware
Tripperware is client side HTTP ware that retries the requests.
Be default this retries safe and idempotent requests 3 times with a linear delay of 100ms. This behaviour can be customized using With* parameter options.
Requests that have http_retry.Enable set on them will always be retried.
type BackoffFunc
type BackoffFunc func(attempt uint) time.Duration
BackoffFunc denotes a family of functions that controll the backoff duration between call retries.
They are called with an identifier of the attempt, and should return a time the system client should
hold off for. If the time returned is longer than the context.Context.Deadline of the request
the deadline of the request takes precedence and the wait will be interrupted before proceeding
with the next iteration.
func BackoffLinear
func BackoffLinear(waitBetween time.Duration) BackoffFunc
BackoffLinear is very simple: it waits for a fixed period of time between calls.
type Option
type Option func(*options)
func WithBackoff
func WithBackoff(bf BackoffFunc) Option
WithBackoff sets the BackoffFunc used to control time between retries.
func WithDecider
func WithDecider(f RequestRetryDeciderFunc) Option
WithDecider is a function that allows users to customize the logic that decides whether a request is retriable.
func WithMax
func WithMax(maxRetries uint) Option
WithMax sets the maximum number of retries on this call, or this interceptor.
func WithResponseDiscarder
func WithResponseDiscarder(f RequestRetryDeciderFunc) Option
WithResponseDiscarder is a function that decides whether a given response should be discarded and another request attempted.
type RequestRetryDeciderFunc
type RequestRetryDeciderFunc func(req *http.Request) bool
RequestRetryDeciderFunc decides whether the given function is idempotent and safe or to retry.
type ResponseDiscarderFunc
type ResponseDiscarderFunc func(resp *http.Response) bool
ResponseDiscarderFunc decides when to discard a response and retry the request again (on true).
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