diff options
Diffstat (limited to 'vendor/github.com/hashicorp/go-retryablehttp/client.go')
| -rw-r--r-- | vendor/github.com/hashicorp/go-retryablehttp/client.go | 500 |
1 files changed, 0 insertions, 500 deletions
diff --git a/vendor/github.com/hashicorp/go-retryablehttp/client.go b/vendor/github.com/hashicorp/go-retryablehttp/client.go deleted file mode 100644 index 21f45e5..0000000 --- a/vendor/github.com/hashicorp/go-retryablehttp/client.go +++ /dev/null @@ -1,500 +0,0 @@ -// The retryablehttp package provides a familiar HTTP client interface with -// automatic retries and exponential backoff. It is a thin wrapper over the -// standard net/http client library and exposes nearly the same public API. -// This makes retryablehttp very easy to drop into existing programs. -// -// retryablehttp performs automatic retries under certain conditions. Mainly, if -// an error is returned by the client (connection errors etc), or if a 500-range -// response is received, then a retry is invoked. Otherwise, the response is -// returned and left to the caller to interpret. -// -// Requests which take a request body should provide a non-nil function -// parameter. The best choice is to provide either a function satisfying -// ReaderFunc which provides multiple io.Readers in an efficient manner, a -// *bytes.Buffer (the underlying raw byte slice will be used) or a raw byte -// slice. As it is a reference type, and we will wrap it as needed by readers, -// we can efficiently re-use the request body without needing to copy it. If an -// io.Reader (such as a *bytes.Reader) is provided, the full body will be read -// prior to the first request, and will be efficiently re-used for any retries. -// ReadSeeker can be used, but some users have observed occasional data races -// between the net/http library and the Seek functionality of some -// implementations of ReadSeeker, so should be avoided if possible. -package retryablehttp - -import ( - "bytes" - "context" - "fmt" - "io" - "io/ioutil" - "log" - "math" - "math/rand" - "net/http" - "net/url" - "os" - "strings" - "time" - - "github.com/hashicorp/go-cleanhttp" -) - -var ( - // Default retry configuration - defaultRetryWaitMin = 1 * time.Second - defaultRetryWaitMax = 30 * time.Second - defaultRetryMax = 4 - - // defaultClient is used for performing requests without explicitly making - // a new client. It is purposely private to avoid modifications. - defaultClient = NewClient() - - // We need to consume response bodies to maintain http connections, but - // limit the size we consume to respReadLimit. - respReadLimit = int64(4096) -) - -// ReaderFunc is the type of function that can be given natively to NewRequest -type ReaderFunc func() (io.Reader, error) - -// LenReader is an interface implemented by many in-memory io.Reader's. Used -// for automatically sending the right Content-Length header when possible. -type LenReader interface { - Len() int -} - -// Request wraps the metadata needed to create HTTP requests. -type Request struct { - // body is a seekable reader over the request body payload. This is - // used to rewind the request data in between retries. - body ReaderFunc - - // Embed an HTTP request directly. This makes a *Request act exactly - // like an *http.Request so that all meta methods are supported. - *http.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. -func (r *Request) WithContext(ctx context.Context) *Request { - r.Request = r.Request.WithContext(ctx) - return r -} - -// NewRequest creates a new wrapped request. -func NewRequest(method, url string, rawBody interface{}) (*Request, error) { - var err error - var body ReaderFunc - var contentLength int64 - - if rawBody != nil { - switch rawBody.(type) { - // If they gave us a function already, great! Use it. - case ReaderFunc: - body = rawBody.(ReaderFunc) - tmp, err := body() - if err != nil { - return nil, err - } - if lr, ok := tmp.(LenReader); ok { - contentLength = int64(lr.Len()) - } - if c, ok := tmp.(io.Closer); ok { - c.Close() - } - - case func() (io.Reader, error): - body = rawBody.(func() (io.Reader, error)) - tmp, err := body() - if err != nil { - return nil, err - } - if lr, ok := tmp.(LenReader); ok { - contentLength = int64(lr.Len()) - } - if c, ok := tmp.(io.Closer); ok { - c.Close() - } - - // If a regular byte slice, we can read it over and over via new - // readers - case []byte: - buf := rawBody.([]byte) - body = func() (io.Reader, error) { - return bytes.NewReader(buf), nil - } - contentLength = int64(len(buf)) - - // If a bytes.Buffer we can read the underlying byte slice over and - // over - case *bytes.Buffer: - buf := rawBody.(*bytes.Buffer) - body = func() (io.Reader, error) { - return bytes.NewReader(buf.Bytes()), nil - } - contentLength = int64(buf.Len()) - - // We prioritize *bytes.Reader here because we don't really want to - // deal with it seeking so want it to match here instead of the - // io.ReadSeeker case. - case *bytes.Reader: - buf, err := ioutil.ReadAll(rawBody.(*bytes.Reader)) - if err != nil { - return nil, err - } - body = func() (io.Reader, error) { - return bytes.NewReader(buf), nil - } - contentLength = int64(len(buf)) - - // Compat case - case io.ReadSeeker: - raw := rawBody.(io.ReadSeeker) - body = func() (io.Reader, error) { - raw.Seek(0, 0) - return ioutil.NopCloser(raw), nil - } - if lr, ok := raw.(LenReader); ok { - contentLength = int64(lr.Len()) - } - - // Read all in so we can reset - case io.Reader: - buf, err := ioutil.ReadAll(rawBody.(io.Reader)) - if err != nil { - return nil, err - } - body = func() (io.Reader, error) { - return bytes.NewReader(buf), nil - } - contentLength = int64(len(buf)) - - default: - return nil, fmt.Errorf("cannot handle type %T", rawBody) - } - } - - httpReq, err := http.NewRequest(method, url, nil) - if err != nil { - return nil, err - } - httpReq.ContentLength = contentLength - - return &Request{body, httpReq}, nil -} - -// 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 RequestLogHook func(*log.Logger, *http.Request, int) - -// 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(). -type ResponseLogHook func(*log.Logger, *http.Response) - -// 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 CheckRetry func(ctx context.Context, resp *http.Response, err error) (bool, error) - -// 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 Backoff func(min, max time.Duration, attemptNum int, resp *http.Response) time.Duration - -// 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 ErrorHandler func(resp *http.Response, err error, numTries int) (*http.Response, error) - -// Client is used to make HTTP requests. It adds additional functionality -// like automatic retries to tolerate minor outages. -type Client struct { - HTTPClient *http.Client // Internal HTTP client. - Logger *log.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 -} - -// NewClient creates a new Client with default settings. -func NewClient() *Client { - return &Client{ - HTTPClient: cleanhttp.DefaultClient(), - Logger: log.New(os.Stderr, "", log.LstdFlags), - RetryWaitMin: defaultRetryWaitMin, - RetryWaitMax: defaultRetryWaitMax, - RetryMax: defaultRetryMax, - CheckRetry: DefaultRetryPolicy, - Backoff: DefaultBackoff, - } -} - -// DefaultRetryPolicy provides a default callback for Client.CheckRetry, which -// will retry on connection errors and server errors. -func DefaultRetryPolicy(ctx context.Context, resp *http.Response, err error) (bool, error) { - // do not retry on context.Canceled or context.DeadlineExceeded - if ctx.Err() != nil { - return false, ctx.Err() - } - - if err != nil { - return true, err - } - // Check the response code. We retry on 500-range responses to allow - // the server time to recover, as 500's are typically not permanent - // errors and may relate to outages on the server side. This will catch - // invalid response codes as well, like 0 and 999. - if resp.StatusCode == 0 || (resp.StatusCode >= 500 && resp.StatusCode != 501) { - return true, nil - } - - return false, nil -} - -// 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 DefaultBackoff(min, max time.Duration, attemptNum int, resp *http.Response) time.Duration { - mult := math.Pow(2, float64(attemptNum)) * float64(min) - sleep := time.Duration(mult) - if float64(sleep) != mult || sleep > max { - sleep = max - } - return sleep -} - -// 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 LinearJitterBackoff(min, max time.Duration, attemptNum int, resp *http.Response) time.Duration { - // attemptNum always starts at zero but we want to start at 1 for multiplication - attemptNum++ - - if max <= min { - // Unclear what to do here, or they are the same, so return min * - // attemptNum - return min * time.Duration(attemptNum) - } - - // Seed rand; doing this every time is fine - rand := rand.New(rand.NewSource(int64(time.Now().Nanosecond()))) - - // Pick a random number that lies somewhere between the min and max and - // multiply by the attemptNum. attemptNum starts at zero so we always - // increment here. We first get a random percentage, then apply that to the - // difference between min and max, and add to min. - jitter := rand.Float64() * float64(max-min) - jitterMin := int64(jitter) + int64(min) - return time.Duration(jitterMin * int64(attemptNum)) -} - -// PassthroughErrorHandler is an ErrorHandler that directly passes through the -// values from the net/http library for the final request. The body is not -// closed. -func PassthroughErrorHandler(resp *http.Response, err error, _ int) (*http.Response, error) { - return resp, err -} - -// Do wraps calling an HTTP method with retries. -func (c *Client) Do(req *Request) (*http.Response, error) { - if c.Logger != nil { - c.Logger.Printf("[DEBUG] %s %s", req.Method, req.URL) - } - - var resp *http.Response - var err error - - for i := 0; ; i++ { - var code int // HTTP response code - - // Always rewind the request body when non-nil. - if req.body != nil { - body, err := req.body() - if err != nil { - return resp, err - } - if c, ok := body.(io.ReadCloser); ok { - req.Request.Body = c - } else { - req.Request.Body = ioutil.NopCloser(body) - } - } - - if c.RequestLogHook != nil { - c.RequestLogHook(c.Logger, req.Request, i) - } - - // Attempt the request - resp, err = c.HTTPClient.Do(req.Request) - if resp != nil { - code = resp.StatusCode - } - - // Check if we should continue with retries. - checkOK, checkErr := c.CheckRetry(req.Request.Context(), resp, err) - - if err != nil { - if c.Logger != nil { - c.Logger.Printf("[ERR] %s %s request failed: %v", req.Method, req.URL, err) - } - } else { - // Call this here to maintain the behavior of logging all requests, - // even if CheckRetry signals to stop. - if c.ResponseLogHook != nil { - // Call the response logger function if provided. - c.ResponseLogHook(c.Logger, resp) - } - } - - // Now decide if we should continue. - if !checkOK { - if checkErr != nil { - err = checkErr - } - return resp, err - } - - // We do this before drainBody beause there's no need for the I/O if - // we're breaking out - remain := c.RetryMax - i - if remain <= 0 { - break - } - - // We're going to retry, consume any response to reuse the connection. - if err == nil && resp != nil { - c.drainBody(resp.Body) - } - - wait := c.Backoff(c.RetryWaitMin, c.RetryWaitMax, i, resp) - desc := fmt.Sprintf("%s %s", req.Method, req.URL) - if code > 0 { - desc = fmt.Sprintf("%s (status: %d)", desc, code) - } - if c.Logger != nil { - c.Logger.Printf("[DEBUG] %s: retrying in %s (%d left)", desc, wait, remain) - } - time.Sleep(wait) - } - - if c.ErrorHandler != nil { - return c.ErrorHandler(resp, err, c.RetryMax+1) - } - - // By default, we close the response body and return an error without - // returning the response - if resp != nil { - resp.Body.Close() - } - return nil, fmt.Errorf("%s %s giving up after %d attempts", - req.Method, req.URL, c.RetryMax+1) -} - -// Try to read the response body so we can reuse this connection. -func (c *Client) drainBody(body io.ReadCloser) { - defer body.Close() - _, err := io.Copy(ioutil.Discard, io.LimitReader(body, respReadLimit)) - if err != nil { - if c.Logger != nil { - c.Logger.Printf("[ERR] error reading response body: %v", err) - } - } -} - -// Get is a shortcut for doing a GET request without making a new client. -func Get(url string) (*http.Response, error) { - return defaultClient.Get(url) -} - -// Get is a convenience helper for doing simple GET requests. -func (c *Client) Get(url string) (*http.Response, error) { - req, err := NewRequest("GET", url, nil) - if err != nil { - return nil, err - } - return c.Do(req) -} - -// Head is a shortcut for doing a HEAD request without making a new client. -func Head(url string) (*http.Response, error) { - return defaultClient.Head(url) -} - -// Head is a convenience method for doing simple HEAD requests. -func (c *Client) Head(url string) (*http.Response, error) { - req, err := NewRequest("HEAD", url, nil) - if err != nil { - return nil, err - } - return c.Do(req) -} - -// Post is a shortcut for doing a POST request without making a new client. -func Post(url, bodyType string, body interface{}) (*http.Response, error) { - return defaultClient.Post(url, bodyType, body) -} - -// Post is a convenience method for doing simple POST requests. -func (c *Client) Post(url, bodyType string, body interface{}) (*http.Response, error) { - req, err := NewRequest("POST", url, body) - if err != nil { - return nil, err - } - req.Header.Set("Content-Type", bodyType) - return c.Do(req) -} - -// PostForm is a shortcut to perform a POST with form data without creating -// a new client. -func PostForm(url string, data url.Values) (*http.Response, error) { - return defaultClient.PostForm(url, data) -} - -// PostForm is a convenience method for doing simple POST operations using -// pre-filled url.Values form data. -func (c *Client) PostForm(url string, data url.Values) (*http.Response, error) { - return c.Post(url, "application/x-www-form-urlencoded", strings.NewReader(data.Encode())) -} |