Documentation
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Index ¶
- Variables
- func DefaultBackoff() ...
- func DefaultClient() *http.Client
- func DefaultHostSprayingTransport() *http.Transport
- func DefaultRetryPolicy() func(ctx context.Context, resp *http.Response, err error) (bool, error)
- func DefaultReusePooledTransport() *http.Transport
- func DefaultSprayingClient() *http.Client
- func Discard(req *Request, resp *http.Response, RespReadLimit int64)
- func ExponentialJitterBackoff() ...
- func FullJitterBackoff() ...
- func HostSprayRetryPolicy() func(ctx context.Context, resp *http.Response, err error) (bool, error)
- func LinearJitterBackoff() ...
- func PassthroughErrorHandler(resp *http.Response, err error, _ int) (*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 Metrics
- type Options
- type ReaderFunc
- type Request
- type RequestLogHook
- type ResponseLogHook
Constants ¶
This section is empty.
Variables ¶
var DefaultOptionsSingle = Options{ RetryWaitMin: 1 * time.Second, RetryWaitMax: 30 * time.Second, Timeout: 30 * time.Second, RetryMax: 5, RespReadLimit: 4096, KillIdleConn: false, MaxPoolSize: 100, ReqPerSec: 10, }
DefaultOptionsSingle contains the default options for host bruteforce scenarios where lots of requests need to be sent to a single host.
var DefaultOptionsSpraying = Options{ RetryWaitMin: 1 * time.Second, RetryWaitMax: 30 * time.Second, Timeout: 30 * time.Second, RetryMax: 5, RespReadLimit: 4096, KillIdleConn: true, MaxPoolSize: 100, ReqPerSec: 10, }
DefaultOptionsSpraying contains the default options for host spraying scenarios where lots of requests need to be sent to different hosts.
Functions ¶
func DefaultBackoff ¶
func DefaultBackoff() func(min, max time.Duration, attemptNum int, resp *http.Response) time.Duration
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 DefaultClient ¶
DefaultPooledClient returns a new http.Client with similar default values to http.Client, but with a shared Transport. Do not use this function for transient clients as it can leak file descriptors over time. Only use this for clients that will be re-used for the same host(s).
func DefaultHostSprayingTransport ¶
DefaultHostSprayingTransport returns a new http.Transport with similar default values to http.DefaultTransport, but with idle connections and keepalives disabled.
func DefaultRetryPolicy ¶
DefaultRetryPolicy provides a default callback for Client.CheckRetry, which will retry on connection errors and server errors.
func DefaultReusePooledTransport ¶
DefaultReusePooledTransport returns a new http.Transport with similar default values to http.DefaultTransport. Do not use this for transient transports as it can leak file descriptors over time. Only use this for transports that will be re-used for the same host(s).
func DefaultSprayingClient ¶
DefaultClient returns a new http.Client with similar default values to http.Client, but with a non-shared Transport, idle connections disabled, and keepalives disabled.
func Discard ¶
Discard is an helper function that discards the response body and closes the underlying connection
func ExponentialJitterBackoff ¶
func ExponentialJitterBackoff() func(min, max time.Duration, attemptNum int, resp *http.Response) time.Duration
ExponentialJitterBackoff provides a callback for Client.Backoff which will perform en exponential 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.
func FullJitterBackoff ¶
func FullJitterBackoff() func(min, max time.Duration, attemptNum int, resp *http.Response) time.Duration
FullJitterBackoff implements capped exponential backoff with jitter. Algorithm is fast because it does not use floating point arithmetics. It returns a random number between [0...n] https://aws.amazon.com/blogs/architecture/exponential-backoff-and-jitter/
func HostSprayRetryPolicy ¶
HostSprayRetryPolicy provides a callback for Client.CheckRetry, which will retry on connection errors and server errors.
func LinearJitterBackoff ¶
func LinearJitterBackoff() func(min, max time.Duration, attemptNum int, resp *http.Response) time.Duration
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, ...)
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 CheckRetry callback to properly close any response body before returning.
type Client ¶
type Client struct {
// HTTPClient is the internal HTTP client.
HTTPClient *http.Client
// 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
// ErrorHandler specifies the custom error handler to use, if any
ErrorHandler ErrorHandler
// 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
// contains filtered or unexported fields
}
Client is used to make HTTP requests. It adds additional functionality like automatic retries to tolerate minor outages.
func NewWithHTTPClient ¶
NewWithHTTPClient creates a new Client with default settings and provided http.Client
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 Metrics ¶
type Metrics struct {
// Failures is the number of failed requests
Failures int
// Retries is the number of retries for the request
Retries int
// DrainErrors is number of errors occured in draining response body
DrainErrors int
}
Metrics contains the metrics about each request
type Options ¶
type Options struct {
// RetryWaitMin is the minimum time to wait for retry
RetryWaitMin time.Duration
// RetryWaitMax is the maximum time to wait for retry
RetryWaitMax time.Duration
// Timeout is the maximum time to wait for the request
Timeout time.Duration
// RetryMax is the maximum number of retries
RetryMax int
// RespReadLimit is the maximum HTTP response size to read for
// connection being reused.
RespReadLimit int64
// Verbose specifies if debug messages should be printed
Verbose bool
// KillIdleConn specifies if all keep-alive connections gets killed
KillIdleConn bool
MaxPoolSize int
ReqPerSec int
Semaphore chan int
RateLimiter <-chan time.Time
}
Options contains configuration options for the client
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
// Metrics contains the metrics for the request.
Metrics Metrics
// contains filtered or unexported fields
}
Request wraps the metadata needed to create HTTP requests. Request is not threadsafe. A request cannot be used by multiple goroutines concurrently.
func FromRequest ¶
FromRequest wraps an http.Request in a retryablehttp.Request
func FromRequestWithTrace ¶
FromRequestWithTrace wraps an http.Request in a retryablehttp.Request with trace enabled
func NewRequest ¶
NewRequest creates a new wrapped request.
func NewRequestWithContext ¶
func NewRequestWithContext(ctx context.Context, method, url string, body interface{}) (*Request, error)
NewRequestWithContext creates a new wrapped request with context
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