Documentation
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Index ¶
- func DefaultBackoff(min, max time.Duration, attemptNum int, resp *http.Response) time.Duration
- func DefaultRetryPolicy(ctx context.Context, resp *http.Response, err error) (bool, error)
- func Get(url string) (*http.Response, error)
- func Head(url string) (*http.Response, error)
- func LinearJitterBackoff(min, max time.Duration, attemptNum int, resp *http.Response) time.Duration
- func PassthroughErrorHandler(resp *http.Response, err error, _ int) (*http.Response, error)
- func Post(url, bodyType string, body interface{}) (*http.Response, error)
- func PostForm(url string, data url.Values) (*http.Response, error)
- type Backoff
- type CheckRetry
- type Client
- func (c *Client) Do(req *Request) (*http.Response, error)
- func (c *Client) Get(url string) (*http.Response, error)
- func (c *Client) Head(url string) (*http.Response, error)
- func (c *Client) Post(url, bodyType string, body interface{}) (*http.Response, error)
- func (c *Client) PostForm(url string, data url.Values) (*http.Response, error)
- type ErrorHandler
- type LenReader
- type Logger
- type ReaderFunc
- type Request
- type RequestLogHook
- type ResponseLogHook
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func DefaultBackoff ¶
DefaultBackoff provides a default callback for Client.Backoff which will perform exponential backoff based on the attempt number and limited by the provided minimum and maximum durations.
func DefaultRetryPolicy ¶
DefaultRetryPolicy provides a default callback for Client.CheckRetry, which will retry on connection errors and server errors.
func LinearJitterBackoff ¶
LinearJitterBackoff provides a callback for Client.Backoff which will perform linear backoff based on the attempt number and with jitter to prevent a thundering herd.
min and max here are *not* absolute values. The number to be multipled by the attempt number will be chosen at random from between them, thus they are bounding the jitter.
For instance: * To get strictly linear backoff of one second increasing each retry, set both to one second (1s, 2s, 3s, 4s, ...) * To get a small amount of jitter centered around one second increasing each retry, set to around one second, such as a min of 800ms and max of 1200ms (892ms, 2102ms, 2945ms, 4312ms, ...) * To get extreme jitter, set to a very wide spread, such as a min of 100ms and a max of 20s (15382ms, 292ms, 51321ms, 35234ms, ...)
func PassthroughErrorHandler ¶
PassthroughErrorHandler is an ErrorHandler that directly passes through the values from the net/http library for the final request. The body is not closed.
Types ¶
type Backoff ¶
Backoff specifies a policy for how long to wait between retries. It is called after a failing request to determine the amount of time that should pass before trying again.
type CheckRetry ¶
CheckRetry specifies a policy for handling retries. It is called following each request with the response and error values returned by the http.Client. If CheckRetry returns false, the Client stops retrying and returns the response to the caller. If CheckRetry returns an error, that error value is returned in lieu of the error from the request. The Client will close any response body when retrying, but if the retry is aborted it is up to the CheckResponse callback to properly close any response body before returning.
type Client ¶
type Client struct {
HTTPClient *http.Client // Internal HTTP client.
Logger Logger // Customer logger instance.
RetryWaitMin time.Duration // Minimum time to wait
RetryWaitMax time.Duration // Maximum time to wait
RetryMax int // Maximum number of retries
// RequestLogHook allows a user-supplied function to be called
// before each retry.
RequestLogHook RequestLogHook
// ResponseLogHook allows a user-supplied function to be called
// with the response from each HTTP request executed.
ResponseLogHook ResponseLogHook
// CheckRetry specifies the policy for handling retries, and is called
// after each request. The default policy is DefaultRetryPolicy.
CheckRetry CheckRetry
// Backoff specifies the policy for how long to wait between retries
Backoff Backoff
// ErrorHandler specifies the custom error handler to use, if any
ErrorHandler ErrorHandler
}
Client is used to make HTTP requests. It adds additional functionality like automatic retries to tolerate minor outages.
type ErrorHandler ¶
ErrorHandler is called if retries are expired, containing the last status from the http library. If not specified, default behavior for the library is to close the body and return an error indicating how many tries were attempted. If overriding this, be sure to close the body if needed.
type LenReader ¶
type LenReader interface {
Len() int
}
LenReader is an interface implemented by many in-memory io.Reader's. Used for automatically sending the right Content-Length header when possible.
type Logger ¶
type Logger interface {
Printf(string, ...interface{})
}
Logger interface allows to use other loggers than standard log.Logger.
type ReaderFunc ¶
ReaderFunc is the type of function that can be given natively to NewRequest
type Request ¶
type Request struct {
// Embed an HTTP request directly. This makes a *Request act exactly
// like an *http.Request so that all meta methods are supported.
*http.Request
// contains filtered or unexported fields
}
Request wraps the metadata needed to create HTTP requests.
func NewRequest ¶
NewRequest creates a new wrapped request.
func (*Request) BodyBytes ¶
BodyBytes allows accessing the request body. It is an analogue to http.Request's Body variable, but it returns a copy of the underlying data rather than consuming it.
This function is not thread-safe; do not call it at the same time as another call, or at the same time this request is being used with Client.Do.
type RequestLogHook ¶
RequestLogHook allows a function to run before each retry. The HTTP request which will be made, and the retry number (0 for the initial request) are available to users. The internal logger is exposed to consumers.
type ResponseLogHook ¶
ResponseLogHook is like RequestLogHook, but allows running a function on each HTTP response. This function will be invoked at the end of every HTTP request executed, regardless of whether a subsequent retry needs to be performed or not. If the response body is read or closed from this method, this will affect the response returned from Do().
Source Files