package azure
// Copyright 2017 Microsoft Corporation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
import (
"bytes"
"context"
"encoding/json"
"fmt"
"io/ioutil"
"net/http"
"net/url"
"strings"
"time"
"github.com/Azure/go-autorest/autorest"
"github.com/Azure/go-autorest/tracing"
)
const (
headerAsyncOperation = "Azure-AsyncOperation"
)
const (
operationInProgress string = "InProgress"
operationCanceled string = "Canceled"
operationFailed string = "Failed"
operationSucceeded string = "Succeeded"
)
var pollingCodes = [...]int{http.StatusNoContent, http.StatusAccepted, http.StatusCreated, http.StatusOK}
// Future provides a mechanism to access the status and results of an asynchronous request.
// Since futures are stateful they should be passed by value to avoid race conditions.
type Future struct {
pt pollingTracker
}
// NewFutureFromResponse returns a new Future object initialized
// with the initial response from an asynchronous operation.
func NewFutureFromResponse(resp *http.Response) (Future, error) {
pt, err := createPollingTracker(resp)
return Future{pt: pt}, err
}
// Response returns the last HTTP response.
func (f Future) Response() *http.Response {
if f.pt == nil {
return nil
}
return f.pt.latestResponse()
}
// Status returns the last status message of the operation.
func (f Future) Status() string {
if f.pt == nil {
return ""
}
return f.pt.pollingStatus()
}
// PollingMethod returns the method used to monitor the status of the asynchronous operation.
func (f Future) PollingMethod() PollingMethodType {
if f.pt == nil {
return PollingUnknown
}
return f.pt.pollingMethod()
}
// DoneWithContext queries the service to see if the operation has completed.
func (f *Future) DoneWithContext(ctx context.Context, sender autorest.Sender) (done bool, err error) {
ctx = tracing.StartSpan(ctx, "github.com/Azure/go-autorest/autorest/azure/async.DoneWithContext")
defer func() {
sc := -1
resp := f.Response()
if resp != nil {
sc = resp.StatusCode
}
tracing.EndSpan(ctx, sc, err)
}()
if f.pt == nil {
return false, autorest.NewError("Future", "Done", "future is not initialized")
}
if f.pt.hasTerminated() {
return true, f.pt.pollingError()
}
if err := f.pt.pollForStatus(ctx, sender); err != nil {
return false, err
}
if err := f.pt.checkForErrors(); err != nil {
return f.pt.hasTerminated(), err
}
if err := f.pt.updatePollingState(f.pt.provisioningStateApplicable()); err != nil {
return false, err
}
if err := f.pt.initPollingMethod(); err != nil {
return false, err
}
if err := f.pt.updatePollingMethod(); err != nil {
return false, err
}
return f.pt.hasTerminated(), f.pt.pollingError()
}
// GetPollingDelay returns a duration the application should wait before checking
// the status of the asynchronous request and true; this value is returned from
// the service via the Retry-After response header. If the header wasn't returned
// then the function returns the zero-value time.Duration and false.
func (f Future) GetPollingDelay() (time.Duration, bool) {
if f.pt == nil {
return 0, false
}
resp := f.pt.latestResponse()
if resp == nil {
return 0, false
}
retry := resp.Header.Get(autorest.HeaderRetryAfter)
if retry == "" {
return 0, false
}
d, err := time.ParseDuration(retry + "s")
if err != nil {
panic(err)
}
return d, true
}
// WaitForCompletionRef will return when one of the following conditions is met: the long
// running operation has completed, the provided context is cancelled, or the client's
// polling duration has been exceeded. It will retry failed polling attempts based on
// the retry value defined in the client up to the maximum retry attempts.
// If no deadline is specified in the context then the client.PollingDuration will be
// used to determine if a default deadline should be used.
// If PollingDuration is greater than zero the value will be used as the context's timeout.
// If PollingDuration is zero then no default deadline will be used.
func (f *Future) WaitForCompletionRef(ctx context.Context, client autorest.Client) (err error) {
ctx = tracing.StartSpan(ctx, "github.com/Azure/go-autorest/autorest/azure/async.WaitForCompletionRef")
defer func() {
sc := -1
resp := f.Response()
if resp != nil {
sc = resp.StatusCode
}
tracing.EndSpan(ctx, sc, err)
}()
cancelCtx := ctx
// if the provided context already has a deadline don't override it
_, hasDeadline := ctx.Deadline()
if d := client.PollingDuration; !hasDeadline && d != 0 {
var cancel context.CancelFunc
cancelCtx, cancel = context.WithTimeout(ctx, d)
defer cancel()
}
done, err := f.DoneWithContext(ctx, client)
for attempts := 0; !done; done, err = f.DoneWithContext(ctx, client) {
if attempts >= client.RetryAttempts {
return autorest.NewErrorWithError(err, "Future", "WaitForCompletion", f.pt.latestResponse(), "the number of retries has been exceeded")
}
// we want delayAttempt to be zero in the non-error case so
// that DelayForBackoff doesn't perform exponential back-off
var delayAttempt int
var delay time.Duration
if err == nil {
// check for Retry-After delay, if not present use the client's polling delay
var ok bool
delay, ok = f.GetPollingDelay()
if !ok {
delay = client.PollingDelay
}
} else {
// there was an error polling for status so perform exponential
// back-off based on the number of attempts using the client's retry
// duration. update attempts after delayAttempt to avoid off-by-one.
delayAttempt = attempts
delay = client.RetryDuration
attempts++
}
// wait until the delay elapses or the context is cancelled
delayElapsed := autorest.DelayForBackoff(delay, delayAttempt, cancelCtx.Done())
if !delayElapsed {
return autorest.NewErrorWithError(cancelCtx.Err(), "Future", "WaitForCompletion", f.pt.latestResponse(), "context has been cancelled")
}
}
return
}
// MarshalJSON implements the json.Marshaler interface.
func (f Future) MarshalJSON() ([]byte, error) {
return json.Marshal(f.pt)
}
// UnmarshalJSON implements the json.Unmarshaler interface.
func (f *Future) UnmarshalJSON(data []byte) error {
// unmarshal into JSON object to determine the tracker type
obj := map[string]interface{}{}
err := json.Unmarshal(data, &obj)
if err != nil {
return err
}
if obj["method"] == nil {
return autorest.NewError("Future", "UnmarshalJSON", "missing 'method' property")
}
method := obj["method"].(string)
switch strings.ToUpper(method) {
case http.MethodDelete:
f.pt = &pollingTrackerDelete{}
case http.MethodPatch:
f.pt = &pollingTrackerPatch{}
case http.MethodPost:
f.pt = &pollingTrackerPost{}
case http.MethodPut:
f.pt = &pollingTrackerPut{}
default:
return autorest.NewError("Future", "UnmarshalJSON", "unsupoorted method '%s'", method)
}
// now unmarshal into the tracker
return json.Unmarshal(data, &f.pt)
}
// PollingURL returns the URL used for retrieving the status of the long-running operation.
func (f Future) PollingURL() string {
if f.pt == nil {
return ""
}
return f.pt.pollingURL()
}
// GetResult should be called once polling has completed successfully.
// It makes the final GET call to retrieve the resultant payload.
func (f Future) GetResult(sender autorest.Sender) (*http.Response, error) {
if f.pt.finalGetURL() == "" {
// we can end up in this situation if the async operation returns a 200
// with no polling URLs. in that case return the response which should
// contain the JSON payload (only do this for successful terminal cases).
if lr := f.pt.latestResponse(); lr != nil && f.pt.hasSucceeded() {
return lr, nil
}
return nil, autorest.NewError("Future", "GetResult", "missing URL for retrieving result")
}
req, err := http.NewRequest(http.MethodGet, f.pt.finalGetURL(), nil)
if err != nil {
return nil, err
}
resp, err := sender.Do(req)
if err == nil && resp.Body != nil {
// copy the body and close it so callers don't have to
defer resp.Body.Close()
b, err := ioutil.ReadAll(resp.Body)
if err != nil {
return resp, err
}
resp.Body = ioutil.NopCloser(bytes.NewReader(b))
}
return resp, err
}
type pollingTracker interface {
// these methods can differ per tracker
// checks the response headers and status code to determine the polling mechanism
updatePollingMethod() error
// checks the response for tracker-specific error conditions
checkForErrors() error
// returns true if provisioning state should be checked
provisioningStateApplicable() bool
// methods common to all trackers
// initializes a tracker's polling URL and method, called for each iteration.
// these values can be overridden by each polling tracker as required.
initPollingMethod() error
// initializes the tracker's internal state, call this when the tracker is created
initializeState() error
// makes an HTTP request to check the status of the LRO
pollForStatus(ctx context.Context, sender autorest.Sender) error
// updates internal tracker state, call this after each call to pollForStatus
updatePollingState(provStateApl bool) error
// returns the error response from the service, can be nil
pollingError() error
// returns the polling method being used
pollingMethod() PollingMethodType
// returns the state of the LRO as returned from the service
pollingStatus() string
// returns the URL used for polling status
pollingURL() string
// returns the URL used for the final GET to retrieve the resource
finalGetURL() string
// returns true if the LRO is in a terminal state
hasTerminated() bool
// returns true if the LRO is in a failed terminal state
hasFailed() bool
// returns true if the LRO is in a successful terminal state
hasSucceeded() bool
// returns the cached HTTP response after a call to pollForStatus(), can be nil
latestResponse() *http.Response
}
type pollingTrackerBase struct {
// resp is the last response, either from the submission of the LRO or from polling
resp *http.Response
// method is the HTTP verb, this is needed for deserialization
Method string `json:"method"`
// rawBody is the raw JSON response body
rawBody map[string]interface{}
// denotes if polling is using async-operation or location header
Pm PollingMethodType `json:"pollingMethod"`
// the URL to poll for status
URI string `json:"pollingURI"`
// the state of the LRO as returned from the service
State string `json:"lroState"`
// the URL to GET for the final result
FinalGetURI string `json:"resultURI"`
// used to hold an error object returned from the service
Err *ServiceError `json:"error,omitempty"`
}
func (pt *pollingTrackerBase) initializeState() error {
// determine the initial polling state based on response body and/or HTTP status
// code. this is applicable to the initial LRO response, not polling responses!
pt.Method = pt.resp.Request.Method
if err := pt.updateRawBody(); err != nil {
return err
}
switch pt.resp.StatusCode {
case http.StatusOK:
if ps := pt.getProvisioningState(); ps != nil {
pt.State = *ps
if pt.hasFailed() {
pt.updateErrorFromResponse()
return pt.pollingError()
}
} else {
pt.State = operationSucceeded
}
case http.StatusCreated:
if ps := pt.getProvisioningState(); ps != nil {
pt.State = *ps
} else {
pt.State = operationInProgress
}
case http.StatusAccepted:
pt.State = operationInProgress
case http.StatusNoContent:
pt.State = operationSucceeded
default:
pt.State = operationFailed
pt.updateErrorFromResponse()
return pt.pollingError()
}
return pt.initPollingMethod()
}
func (pt pollingTrackerBase) getProvisioningState() *string {
if pt.rawBody != nil && pt.rawBody["properties"] != nil {
p := pt.rawBody["properties"].(map[string]interface{})
if ps := p["provisioningState"]; ps != nil {
s := ps.(string)
return &s
}
}
return nil
}
func (pt *pollingTrackerBase) updateRawBody() error {
pt.rawBody = map[string]interface{}{}
if pt.resp.ContentLength != 0 {
defer pt.resp.Body.Close()
b, err := ioutil.ReadAll(pt.resp.Body)
if err != nil {
return autorest.NewErrorWithError(err, "pollingTrackerBase", "updateRawBody", nil, "failed to read response body")
}
// observed in 204 responses over HTTP/2.0; the content length is -1 but body is empty
if len(b) == 0 {
return nil
}
// put the body back so it's available to other callers
pt.resp.Body = ioutil.NopCloser(bytes.NewReader(b))
if err = json.Unmarshal(b, &pt.rawBody); err != nil {
return autorest.NewErrorWithError(err, "pollingTrackerBase", "updateRawBody", nil, "failed to unmarshal response body")
}
}
return nil
}
func (pt *pollingTrackerBase) pollForStatus(ctx context.Context, sender autorest.Sender) error {
req, err := http.NewRequest(http.MethodGet, pt.URI, nil)
if err != nil {
return autorest.NewErrorWithError(err, "pollingTrackerBase", "pollForStatus", nil, "failed to create HTTP request")
}
req = req.WithContext(ctx)
preparer := autorest.CreatePreparer(autorest.GetPrepareDecorators(ctx)...)
req, err = preparer.Prepare(req)
if err != nil {
return autorest.NewErrorWithError(err, "pollingTrackerBase", "pollForStatus", nil, "failed preparing HTTP request")
}
pt.resp, err = sender.Do(req)
if err != nil {
return autorest.NewErrorWithError(err, "pollingTrackerBase", "pollForStatus", nil, "failed to send HTTP request")
}
if autorest.ResponseHasStatusCode(pt.resp, pollingCodes[:]...) {
// reset the service error on success case
pt.Err = nil
err = pt.updateRawBody()
} else {
// check response body for error content
pt.updateErrorFromResponse()
err = pt.pollingError()
}
return err
}
// attempts to unmarshal a ServiceError type from the response body.
// if that fails then make a best attempt at creating something meaningful.
// NOTE: this assumes that the async operation has failed.
func (pt *pollingTrackerBase) updateErrorFromResponse() {
var err error
if pt.resp.ContentLength != 0 {
type respErr struct {
ServiceError *ServiceError `json:"error"`
}
re := respErr{}
defer pt.resp.Body.Close()
var b []byte
if b, err = ioutil.ReadAll(pt.resp.Body); err != nil || len(b) == 0 {
goto Default
}
if err = json.Unmarshal(b, &re); err != nil {
goto Default
}
// unmarshalling the error didn't yield anything, try unwrapped error
if re.ServiceError == nil {
err = json.Unmarshal(b, &re.ServiceError)
if err != nil {
goto Default
}
}
// the unmarshaller will ensure re.ServiceError is non-nil
// even if there was no content unmarshalled so check the code.
if re.ServiceError.Code != "" {
pt.Err = re.ServiceError
return
}
}
Default:
se := &ServiceError{
Code: pt.pollingStatus(),
Message: "The async operation failed.",
}
if err != nil {
se.InnerError = make(map[string]interface{})
se.InnerError["unmarshalError"] = err.Error()
}
// stick the response body into the error object in hopes
// it contains something useful to help diagnose the failure.
if len(pt.rawBody) > 0 {
se.AdditionalInfo = []map[string]interface{}{
pt.rawBody,
}
}
pt.Err = se
}
func (pt *pollingTrackerBase) updatePollingState(provStateApl bool) error {
if pt.Pm == PollingAsyncOperation && pt.rawBody["status"] != nil {
pt.State = pt.rawBody["status"].(string)
} else {
if pt.resp.StatusCode == http.StatusAccepted {
pt.State = operationInProgress
} else if provStateApl {
if ps := pt.getProvisioningState(); ps != nil {
pt.State = *ps
} else {
pt.State = operationSucceeded
}
} else {
return autorest.NewError("pollingTrackerBase", "updatePollingState", "the response from the async operation has an invalid status code")
}
}
// if the operation has failed update the error state
if pt.hasFailed() {
pt.updateErrorFromResponse()
}
return nil
}
func (pt pollingTrackerBase) pollingError() error {
if pt.Err == nil {
return nil
}
return pt.Err
}
func (pt pollingTrackerBase) pollingMethod() PollingMethodType {
return pt.Pm
}
func (pt pollingTrackerBase) pollingStatus() string {
return pt.State
}
func (pt pollingTrackerBase) pollingURL() string {
return pt.URI
}
func (pt pollingTrackerBase) finalGetURL() string {
return pt.FinalGetURI
}
func (pt pollingTrackerBase) hasTerminated() bool {
return strings.EqualFold(pt.State, operationCanceled) || strings.EqualFold(pt.State, operationFailed) || strings.EqualFold(pt.State, operationSucceeded)
}
func (pt pollingTrackerBase) hasFailed() bool {
return strings.EqualFold(pt.State, operationCanceled) || strings.EqualFold(pt.State, operationFailed)
}
func (pt pollingTrackerBase) hasSucceeded() bool {
return strings.EqualFold(pt.State, operationSucceeded)
}
func (pt pollingTrackerBase) latestResponse() *http.Response {
return pt.resp
}
// error checking common to all trackers
func (pt pollingTrackerBase) baseCheckForErrors() error {
// for Azure-AsyncOperations the response body cannot be nil or empty
if pt.Pm == PollingAsyncOperation {
if pt.resp.Body == nil || pt.resp.ContentLength == 0 {
return autorest.NewError("pollingTrackerBase", "baseCheckForErrors", "for Azure-AsyncOperation response body cannot be nil")
}
if pt.rawBody["status"] == nil {
return autorest.NewError("pollingTrackerBase", "baseCheckForErrors", "missing status property in Azure-AsyncOperation response body")
}
}
return nil
}
// default initialization of polling URL/method. each verb tracker will update this as required.
func (pt *pollingTrackerBase) initPollingMethod() error {
if ao, err := getURLFromAsyncOpHeader(pt.resp); err != nil {
return err
} else if ao != "" {
pt.URI = ao
pt.Pm = PollingAsyncOperation
return nil
}
if lh, err := getURLFromLocationHeader(pt.resp); err != nil {
return err
} else if lh != "" {
pt.URI = lh
pt.Pm = PollingLocation
return nil
}
// it's ok if we didn't find a polling header, this will be handled elsewhere
return nil
}
// DELETE
type pollingTrackerDelete struct {
pollingTrackerBase
}
func (pt *pollingTrackerDelete) updatePollingMethod() error {
// for 201 the Location header is required
if pt.resp.StatusCode == http.StatusCreated {
if lh, err := getURLFromLocationHeader(pt.resp); err != nil {
return err
} else if lh == "" {
return autorest.NewError("pollingTrackerDelete", "updateHeaders", "missing Location header in 201 response")
} else {
pt.URI = lh
}
pt.Pm = PollingLocation
pt.FinalGetURI = pt.URI
}
// for 202 prefer the Azure-AsyncOperation header but fall back to Location if necessary
if pt.resp.StatusCode == http.StatusAccepted {
ao, err := getURLFromAsyncOpHeader(pt.resp)
if err != nil {
return err
} else if ao != "" {
pt.URI = ao
pt.Pm = PollingAsyncOperation
}
// if the Location header is invalid and we already have a polling URL
// then we don't care if the Location header URL is malformed.
if lh, err := getURLFromLocationHeader(pt.resp); err != nil && pt.URI == "" {
return err
} else if lh != "" {
if ao == "" {
pt.URI = lh
pt.Pm = PollingLocation
}
// when both headers are returned we use the value in the Location header for the final GET
pt.FinalGetURI = lh
}
// make sure a polling URL was found
if pt.URI == "" {
return autorest.NewError("pollingTrackerPost", "updateHeaders", "didn't get any suitable polling URLs in 202 response")
}
}
return nil
}
func (pt pollingTrackerDelete) checkForErrors() error {
return pt.baseCheckForErrors()
}
func (pt pollingTrackerDelete) provisioningStateApplicable() bool {
return pt.resp.StatusCode == http.StatusOK || pt.resp.StatusCode == http.StatusNoContent
}
// PATCH
type pollingTrackerPatch struct {
pollingTrackerBase
}
func (pt *pollingTrackerPatch) updatePollingMethod() error {
// by default we can use the original URL for polling and final GET
if pt.URI == "" {
pt.URI = pt.resp.Request.URL.String()
}
if pt.FinalGetURI == "" {
pt.FinalGetURI = pt.resp.Request.URL.String()
}
if pt.Pm == PollingUnknown {
pt.Pm = PollingRequestURI
}
// for 201 it's permissible for no headers to be returned
if pt.resp.StatusCode == http.StatusCreated {
if ao, err := getURLFromAsyncOpHeader(pt.resp); err != nil {
return err
} else if ao != "" {
pt.URI = ao
pt.Pm = PollingAsyncOperation
}
}
// for 202 prefer the Azure-AsyncOperation header but fall back to Location if necessary
// note the absence of the "final GET" mechanism for PATCH
if pt.resp.StatusCode == http.StatusAccepted {
ao, err := getURLFromAsyncOpHeader(pt.resp)
if err != nil {
return err
} else if ao != "" {
pt.URI = ao
pt.Pm = PollingAsyncOperation
}
if ao == "" {
if lh, err := getURLFromLocationHeader(pt.resp); err != nil {
return err
} else if lh == "" {
return autorest.NewError("pollingTrackerPatch", "updateHeaders", "didn't get any suitable polling URLs in 202 response")
} else {
pt.URI = lh
pt.Pm = PollingLocation
}
}
}
return nil
}
func (pt pollingTrackerPatch) checkForErrors() error {
return pt.baseCheckForErrors()
}
func (pt pollingTrackerPatch) provisioningStateApplicable() bool {
return pt.resp.StatusCode == http.StatusOK || pt.resp.StatusCode == http.StatusCreated
}
// POST
type pollingTrackerPost struct {
pollingTrackerBase
}
func (pt *pollingTrackerPost) updatePollingMethod() error {
// 201 requires Location header
if pt.resp.StatusCode == http.StatusCreated {
if lh, err := getURLFromLocationHeader(pt.resp); err != nil {
return err
} else if lh == "" {
return autorest.NewError("pollingTrackerPost", "updateHeaders", "missing Location header in 201 response")
} else {
pt.URI = lh
pt.FinalGetURI = lh
pt.Pm = PollingLocation
}
}
// for 202 prefer the Azure-AsyncOperation header but fall back to Location if necessary
if pt.resp.StatusCode == http.StatusAccepted {
ao, err := getURLFromAsyncOpHeader(pt.resp)
if err != nil {
return err
} else if ao != "" {
pt.URI = ao
pt.Pm = PollingAsyncOperation
}
// if the Location header is invalid and we already have a polling URL
// then we don't care if the Location header URL is malformed.
if lh, err := getURLFromLocationHeader(pt.resp); err != nil && pt.URI == "" {
return err
} else if lh != "" {
if ao == "" {
pt.URI = lh
pt.Pm = PollingLocation
}
// when both headers are returned we use the value in the Location header for the final GET
pt.FinalGetURI = lh
}
// make sure a polling URL was found
if pt.URI == "" {
return autorest.NewError("pollingTrackerPost", "updateHeaders", "didn't get any suitable polling URLs in 202 response")
}
}
return nil
}
func (pt pollingTrackerPost) checkForErrors() error {
return pt.baseCheckForErrors()
}
func (pt pollingTrackerPost) provisioningStateApplicable() bool {
return pt.resp.StatusCode == http.StatusOK || pt.resp.StatusCode == http.StatusNoContent
}
// PUT
type pollingTrackerPut struct {
pollingTrackerBase
}
func (pt *pollingTrackerPut) updatePollingMethod() error {
// by default we can use the original URL for polling and final GET
if pt.URI == "" {
pt.URI = pt.resp.Request.URL.String()
}
if pt.FinalGetURI == "" {
pt.FinalGetURI = pt.resp.Request.URL.String()
}
if pt.Pm == PollingUnknown {
pt.Pm = PollingRequestURI
}
// for 201 it's permissible for no headers to be returned
if pt.resp.StatusCode == http.StatusCreated {
if ao, err := getURLFromAsyncOpHeader(pt.resp); err != nil {
return err
} else if ao != "" {
pt.URI = ao
pt.Pm = PollingAsyncOperation
}
}
// for 202 prefer the Azure-AsyncOperation header but fall back to Location if necessary
if pt.resp.StatusCode == http.StatusAccepted {
ao, err := getURLFromAsyncOpHeader(pt.resp)
if err != nil {
return err
} else if ao != "" {
pt.URI = ao
pt.Pm = PollingAsyncOperation
}
// if the Location header is invalid and we already have a polling URL
// then we don't care if the Location header URL is malformed.
if lh, err := getURLFromLocationHeader(pt.resp); err != nil && pt.URI == "" {
return err
} else if lh != "" {
if ao == "" {
pt.URI = lh
pt.Pm = PollingLocation
}
}
// make sure a polling URL was found
if pt.URI == "" {
return autorest.NewError("pollingTrackerPut", "updateHeaders", "didn't get any suitable polling URLs in 202 response")
}
}
return nil
}
func (pt pollingTrackerPut) checkForErrors() error {
err := pt.baseCheckForErrors()
if err != nil {
return err
}
// if there are no LRO headers then the body cannot be empty
ao, err := getURLFromAsyncOpHeader(pt.resp)
if err != nil {
return err
}
lh, err := getURLFromLocationHeader(pt.resp)
if err != nil {
return err
}
if ao == "" && lh == "" && len(pt.rawBody) == 0 {
return autorest.NewError("pollingTrackerPut", "checkForErrors", "the response did not contain a body")
}
return nil
}
func (pt pollingTrackerPut) provisioningStateApplicable() bool {
return pt.resp.StatusCode == http.StatusOK || pt.resp.StatusCode == http.StatusCreated
}
// creates a polling tracker based on the verb of the original request
func createPollingTracker(resp *http.Response) (pollingTracker, error) {
var pt pollingTracker
switch strings.ToUpper(resp.Request.Method) {
case http.MethodDelete:
pt = &pollingTrackerDelete{pollingTrackerBase: pollingTrackerBase{resp: resp}}
case http.MethodPatch:
pt = &pollingTrackerPatch{pollingTrackerBase: pollingTrackerBase{resp: resp}}
case http.MethodPost:
pt = &pollingTrackerPost{pollingTrackerBase: pollingTrackerBase{resp: resp}}
case http.MethodPut:
pt = &pollingTrackerPut{pollingTrackerBase: pollingTrackerBase{resp: resp}}
default:
return nil, autorest.NewError("azure", "createPollingTracker", "unsupported HTTP method %s", resp.Request.Method)
}
if err := pt.initializeState(); err != nil {
return pt, err
}
// this initializes the polling header values, we do this during creation in case the
// initial response send us invalid values; this way the API call will return a non-nil
// error (not doing this means the error shows up in Future.Done)
return pt, pt.updatePollingMethod()
}
// gets the polling URL from the Azure-AsyncOperation header.
// ensures the URL is well-formed and absolute.
func getURLFromAsyncOpHeader(resp *http.Response) (string, error) {
s := resp.Header.Get(http.CanonicalHeaderKey(headerAsyncOperation))
if s == "" {
return "", nil
}
if !isValidURL(s) {
return "", autorest.NewError("azure", "getURLFromAsyncOpHeader", "invalid polling URL '%s'", s)
}
return s, nil
}
// gets the polling URL from the Location header.
// ensures the URL is well-formed and absolute.
func getURLFromLocationHeader(resp *http.Response) (string, error) {
s := resp.Header.Get(http.CanonicalHeaderKey(autorest.HeaderLocation))
if s == "" {
return "", nil
}
if !isValidURL(s) {
return "", autorest.NewError("azure", "getURLFromLocationHeader", "invalid polling URL '%s'", s)
}
return s, nil
}
// verify that the URL is valid and absolute
func isValidURL(s string) bool {
u, err := url.Parse(s)
return err == nil && u.IsAbs()
}
// PollingMethodType defines a type used for enumerating polling mechanisms.
type PollingMethodType string
const (
// PollingAsyncOperation indicates the polling method uses the Azure-AsyncOperation header.
PollingAsyncOperation PollingMethodType = "AsyncOperation"
// PollingLocation indicates the polling method uses the Location header.
PollingLocation PollingMethodType = "Location"
// PollingRequestURI indicates the polling method uses the original request URI.
PollingRequestURI PollingMethodType = "RequestURI"
// PollingUnknown indicates an unknown polling method and is the default value.
PollingUnknown PollingMethodType = ""
)
// AsyncOpIncompleteError is the type that's returned from a future that has not completed.
type AsyncOpIncompleteError struct {
// FutureType is the name of the type composed of a azure.Future.
FutureType string
}
// Error returns an error message including the originating type name of the error.
func (e AsyncOpIncompleteError) Error() string {
return fmt.Sprintf("%s: asynchronous operation has not completed", e.FutureType)
}
// NewAsyncOpIncompleteError creates a new AsyncOpIncompleteError with the specified parameters.
func NewAsyncOpIncompleteError(futureType string) AsyncOpIncompleteError {
return AsyncOpIncompleteError{
FutureType: futureType,
}
}