http

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 Go to latest Published: Nov 30, 2021 License: MIT Imports: 19 Imported by: 0

Documentation

Index

Constants

This section is empty.

Variables

View Source 
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.

View Source 
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 

func DefaultClient() *http.Client

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 

func DefaultHostSprayingTransport() *http.Transport

DefaultHostSprayingTransport returns a new http.Transport with similar default values to http.DefaultTransport, but with idle connections and keepalives disabled.

func DefaultRetryPolicy 

func DefaultRetryPolicy() func(ctx context.Context, resp *http.Response, err error) (bool, error)

DefaultRetryPolicy provides a default callback for Client.CheckRetry, which will retry on connection errors and server errors.

func DefaultReusePooledTransport 

func DefaultReusePooledTransport() *http.Transport

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 

func DefaultSprayingClient() *http.Client

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 

func Discard(req *Request, resp *http.Response, RespReadLimit int64)

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 

func HostSprayRetryPolicy() func(ctx context.Context, resp *http.Response, err error) (bool, error)

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, ...)

func PassthroughErrorHandler 

func PassthroughErrorHandler(resp *http.Response, err error, _ int) (*http.Response, error)

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 

type Backoff func(min, max time.Duration, attemptNum int, resp *http.Response) time.Duration

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 

type CheckRetry func(ctx context.Context, resp *http.Response, err error) (bool, error)

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 NewClient 

func NewClient(options Options) *Client

NewClient creates a new Client with default settings.

func NewWithHTTPClient 

func NewWithHTTPClient(client *http.Client, options Options) *Client

NewWithHTTPClient creates a new Client with default settings and provided http.Client

func (*Client) Do 

func (c *Client) Do(req *Request) (*http.Response, error)

Do wraps calling an HTTP method with retries.

func (*Client) Get 

func (c *Client) Get(url string) (*http.Response, error)

Get is a convenience helper for doing simple GET requests.

func (*Client) Head 

func (c *Client) Head(url string) (*http.Response, error)

Head is a convenience method for doing simple HEAD requests.

func (*Client) Post 

func (c *Client) Post(url, bodyType string, body interface{}) (*http.Response, error)

Post is a convenience method for doing simple POST requests.

func (*Client) PostForm 

func (c *Client) PostForm(url string, data url.Values) (*http.Response, error)

PostForm is a convenience method for doing simple POST operations using pre-filled url.Values form data.

type ErrorHandler 

type ErrorHandler func(resp *http.Response, err error, numTries int) (*http.Response, error)

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 

type ReaderFunc func() (io.Reader, error)

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 

func FromRequest(r *http.Request) (*Request, error)

FromRequest wraps an http.Request in a retryablehttp.Request

func FromRequestWithTrace 

func FromRequestWithTrace(r *http.Request) (*Request, error)

FromRequestWithTrace wraps an http.Request in a retryablehttp.Request with trace enabled

func NewRequest 

func NewRequest(method, url string, body interface{}) (*Request, error)

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 

func (r *Request) BodyBytes() ([]byte, error)

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.

func (*Request) WithContext 

func (r *Request) WithContext(ctx context.Context) *Request

WithContext returns wrapped Request with a shallow copy of underlying *http.Request with its context changed to ctx. The provided ctx must be non-nil.

type RequestLogHook 

type RequestLogHook func(*http.Request, int)

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 

type ResponseLogHook func(*http.Response)

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

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