Retryable HTTP client in Go
The
retryablehttppackage provides a familiar HTTP client interface with automatic retries and exponential backoff. It is a thin wrapper over the standard
net/httpclient library and exposes nearly the same public API. This makes
retryablehttpvery easy to drop into existing programs.
retryablehttpperforms automatic retries under certain conditions. Mainly, if an error is returned by the client (connection errors, etc.), or if a 500-range response code is received (except 501), then a retry is invoked after a wait period. Otherwise, the response is returned and left to the caller to interpret.
The main difference from
net/httpis that requests which take a request body (POST/PUT et. al) can have the body provided in a number of ways (some more or less efficient) that allow "rewinding" the request body if the initial request fails so that the full request can be attempted again. See the godoc for more details.
Version 0.6.0 and before are compatible with Go prior to 1.12. From 0.6.1 onward, Go 1.12+ is required. From 0.6.7 onward, Go 1.13+ is required.
Using this library should look almost identical to what you would do with
net/http. The most simple example of a GET request is shown below:
resp, err := retryablehttp.Get("/foo") if err != nil { panic(err) }
The returned response object is an
*http.Response, the same thing you would usually get from
net/http. Had the request failed one or more times, the above call would block and retry with exponential backoff.
*http.Clientwith retries
It's possible to convert a
*retryablehttp.Clientdirectly to a
*http.Client. This makes use of retryablehttp broadly applicable with minimal effort. Simply configure a
*retryablehttp.Clientas you wish, and then call
StandardClient():
retryClient := retryablehttp.NewClient() retryClient.RetryMax = 10standardClient := retryClient.StandardClient() // *http.Client
For more usage and examples see the godoc.