traefik/vendor/github.com/Azure/go-autorest/autorest/client.go
2017-04-07 11:52:18 +01:00

235 lines
7.3 KiB
Go

package autorest
import (
"bytes"
"fmt"
"io"
"io/ioutil"
"log"
"net/http"
"net/http/cookiejar"
"runtime"
"time"
)
const (
// DefaultPollingDelay is a reasonable delay between polling requests.
DefaultPollingDelay = 60 * time.Second
// DefaultPollingDuration is a reasonable total polling duration.
DefaultPollingDuration = 15 * time.Minute
// DefaultRetryAttempts is number of attempts for retry status codes (5xx).
DefaultRetryAttempts = 3
)
var (
// defaultUserAgent builds a string containing the Go version, system archityecture and OS,
// and the go-autorest version.
defaultUserAgent = fmt.Sprintf("Go/%s (%s-%s) go-autorest/%s",
runtime.Version(),
runtime.GOARCH,
runtime.GOOS,
Version(),
)
statusCodesForRetry = []int{
http.StatusRequestTimeout, // 408
http.StatusInternalServerError, // 500
http.StatusBadGateway, // 502
http.StatusServiceUnavailable, // 503
http.StatusGatewayTimeout, // 504
}
)
const (
requestFormat = `HTTP Request Begin ===================================================
%s
===================================================== HTTP Request End
`
responseFormat = `HTTP Response Begin ===================================================
%s
===================================================== HTTP Response End
`
)
// Response serves as the base for all responses from generated clients. It provides access to the
// last http.Response.
type Response struct {
*http.Response `json:"-"`
}
// LoggingInspector implements request and response inspectors that log the full request and
// response to a supplied log.
type LoggingInspector struct {
Logger *log.Logger
}
// WithInspection returns a PrepareDecorator that emits the http.Request to the supplied logger. The
// body is restored after being emitted.
//
// Note: Since it reads the entire Body, this decorator should not be used where body streaming is
// important. It is best used to trace JSON or similar body values.
func (li LoggingInspector) WithInspection() PrepareDecorator {
return func(p Preparer) Preparer {
return PreparerFunc(func(r *http.Request) (*http.Request, error) {
var body, b bytes.Buffer
defer r.Body.Close()
r.Body = ioutil.NopCloser(io.TeeReader(r.Body, &body))
if err := r.Write(&b); err != nil {
return nil, fmt.Errorf("Failed to write response: %v", err)
}
li.Logger.Printf(requestFormat, b.String())
r.Body = ioutil.NopCloser(&body)
return p.Prepare(r)
})
}
}
// ByInspecting returns a RespondDecorator that emits the http.Response to the supplied logger. The
// body is restored after being emitted.
//
// Note: Since it reads the entire Body, this decorator should not be used where body streaming is
// important. It is best used to trace JSON or similar body values.
func (li LoggingInspector) ByInspecting() RespondDecorator {
return func(r Responder) Responder {
return ResponderFunc(func(resp *http.Response) error {
var body, b bytes.Buffer
defer resp.Body.Close()
resp.Body = ioutil.NopCloser(io.TeeReader(resp.Body, &body))
if err := resp.Write(&b); err != nil {
return fmt.Errorf("Failed to write response: %v", err)
}
li.Logger.Printf(responseFormat, b.String())
resp.Body = ioutil.NopCloser(&body)
return r.Respond(resp)
})
}
}
// Client is the base for autorest generated clients. It provides default, "do nothing"
// implementations of an Authorizer, RequestInspector, and ResponseInspector. It also returns the
// standard, undecorated http.Client as a default Sender.
//
// Generated clients should also use Error (see NewError and NewErrorWithError) for errors and
// return responses that compose with Response.
//
// Most customization of generated clients is best achieved by supplying a custom Authorizer, custom
// RequestInspector, and / or custom ResponseInspector. Users may log requests, implement circuit
// breakers (see https://msdn.microsoft.com/en-us/library/dn589784.aspx) or otherwise influence
// sending the request by providing a decorated Sender.
type Client struct {
Authorizer Authorizer
Sender Sender
RequestInspector PrepareDecorator
ResponseInspector RespondDecorator
// PollingDelay sets the polling frequency used in absence of a Retry-After HTTP header
PollingDelay time.Duration
// PollingDuration sets the maximum polling time after which an error is returned.
PollingDuration time.Duration
// RetryAttempts sets the default number of retry attempts for client.
RetryAttempts int
// RetryDuration sets the delay duration for retries.
RetryDuration time.Duration
// UserAgent, if not empty, will be set as the HTTP User-Agent header on all requests sent
// through the Do method.
UserAgent string
Jar http.CookieJar
}
// NewClientWithUserAgent returns an instance of a Client with the UserAgent set to the passed
// string.
func NewClientWithUserAgent(ua string) Client {
c := Client{
PollingDelay: DefaultPollingDelay,
PollingDuration: DefaultPollingDuration,
RetryAttempts: DefaultRetryAttempts,
RetryDuration: 30 * time.Second,
UserAgent: defaultUserAgent,
}
c.AddToUserAgent(ua)
return c
}
// AddToUserAgent adds an extension to the current user agent
func (c *Client) AddToUserAgent(extension string) error {
if extension != "" {
c.UserAgent = fmt.Sprintf("%s %s", c.UserAgent, extension)
return nil
}
return fmt.Errorf("Extension was empty, User Agent stayed as %s", c.UserAgent)
}
// Do implements the Sender interface by invoking the active Sender after applying authorization.
// If Sender is not set, it uses a new instance of http.Client. In both cases it will, if UserAgent
// is set, apply set the User-Agent header.
func (c Client) Do(r *http.Request) (*http.Response, error) {
if r.UserAgent() == "" {
r, _ = Prepare(r,
WithUserAgent(c.UserAgent))
}
r, err := Prepare(r,
c.WithInspection(),
c.WithAuthorization())
if err != nil {
return nil, NewErrorWithError(err, "autorest/Client", "Do", nil, "Preparing request failed")
}
resp, err := SendWithSender(c.sender(), r,
DoRetryForStatusCodes(c.RetryAttempts, c.RetryDuration, statusCodesForRetry...))
Respond(resp,
c.ByInspecting())
return resp, err
}
// sender returns the Sender to which to send requests.
func (c Client) sender() Sender {
if c.Sender == nil {
j, _ := cookiejar.New(nil)
return &http.Client{Jar: j}
}
return c.Sender
}
// WithAuthorization is a convenience method that returns the WithAuthorization PrepareDecorator
// from the current Authorizer. If not Authorizer is set, it uses the NullAuthorizer.
func (c Client) WithAuthorization() PrepareDecorator {
return c.authorizer().WithAuthorization()
}
// authorizer returns the Authorizer to use.
func (c Client) authorizer() Authorizer {
if c.Authorizer == nil {
return NullAuthorizer{}
}
return c.Authorizer
}
// WithInspection is a convenience method that passes the request to the supplied RequestInspector,
// if present, or returns the WithNothing PrepareDecorator otherwise.
func (c Client) WithInspection() PrepareDecorator {
if c.RequestInspector == nil {
return WithNothing()
}
return c.RequestInspector
}
// ByInspecting is a convenience method that passes the response to the supplied ResponseInspector,
// if present, or returns the ByIgnoring RespondDecorator otherwise.
func (c Client) ByInspecting() RespondDecorator {
if c.ResponseInspector == nil {
return ByIgnoring()
}
return c.ResponseInspector
}