azure_armclient.go

/*
Copyright 2020 The Kubernetes Authors.

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.
*/

package armclient

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"html"
	"io/ioutil"
	"net/http"
	"net/http/httputil"
	"net/url"
	"strings"
	"sync"
	"time"
	"unicode"

	"sigs.k8s.io/cloud-provider-azure/pkg/azureclients"

	"github.com/Azure/go-autorest/autorest"
	"github.com/Azure/go-autorest/autorest/azure"

	"k8s.io/klog/v2"
	"sigs.k8s.io/cloud-provider-azure/pkg/retry"
	"sigs.k8s.io/cloud-provider-azure/pkg/version"
)

var _ Interface = &Client{}

// Client implements ARM client Interface.
type Client struct {
	client           autorest.Client
	baseURI          string
	apiVersion       string
	regionalEndpoint string
}

// New creates a ARM client
func New(authorizer autorest.Authorizer, clientConfig azureclients.ClientConfig, baseURI, apiVersion string, sendDecoraters ...autorest.SendDecorator) *Client {
	restClient := autorest.NewClientWithUserAgent(clientConfig.UserAgent)
	restClient.Authorizer = authorizer

	if clientConfig.UserAgent == "" {
		restClient.UserAgent = GetUserAgent(restClient)
	}

	if clientConfig.RestClientConfig.PollingDelay == nil {
		restClient.PollingDelay = 5 * time.Second
	} else {
		restClient.PollingDelay = *clientConfig.RestClientConfig.PollingDelay
	}

	if clientConfig.RestClientConfig.RetryAttempts == nil {
		restClient.RetryAttempts = 3
	} else {
		restClient.RetryAttempts = *clientConfig.RestClientConfig.RetryAttempts
	}

	if clientConfig.RestClientConfig.RetryDuration == nil {
		restClient.RetryDuration = 1 * time.Second
	} else {
		restClient.RetryDuration = *clientConfig.RestClientConfig.RetryDuration
	}

	backoff := clientConfig.Backoff
	if backoff == nil {
		backoff = &retry.Backoff{}
	}
	if backoff.Steps == 0 {
		// 1 steps means no retry.
		backoff.Steps = 1
	}

	url, _ := url.Parse(baseURI)

	client := &Client{
		client:           restClient,
		baseURI:          baseURI,
		apiVersion:       apiVersion,
		regionalEndpoint: fmt.Sprintf("%s.%s", clientConfig.Location, url.Host),
	}
	client.client.Sender = autorest.DecorateSender(client.client,
		autorest.DoCloseIfError(),
		retry.DoExponentialBackoffRetry(backoff),
		DoHackRegionalRetryDecorator(client),
	)

	client.client.Sender = autorest.DecorateSender(client.client.Sender, sendDecoraters...)

	return client
}

// GetUserAgent gets the autorest client with a user agent that
// includes "kubernetes" and the full kubernetes git version string
// example:
// Azure-SDK-for-Go/7.0.1 arm-network/2016-09-01; kubernetes-cloudprovider/v1.17.0;
func GetUserAgent(client autorest.Client) string {
	k8sVersion := version.Get().GitVersion
	return fmt.Sprintf("%s; kubernetes-cloudprovider/%s", client.UserAgent, k8sVersion)
}

// NormalizeAzureRegion returns a normalized Azure region with white spaces removed and converted to lower case
func NormalizeAzureRegion(name string) string {
	region := ""
	for _, runeValue := range name {
		if !unicode.IsSpace(runeValue) {
			region += string(runeValue)
		}
	}
	return strings.ToLower(region)
}

// DoExponentialBackoffRetry returns an autorest.SendDecorator which performs retry with customizable backoff policy.
func DoHackRegionalRetryDecorator(c *Client) autorest.SendDecorator {
	return func(s autorest.Sender) autorest.Sender {
		return autorest.SenderFunc(func(request *http.Request) (*http.Response, error) {
			response, rerr := s.Do(request)
			if response == nil {
				klog.V(2).Infof("response is empty")
				return response, rerr
			}
			if rerr == nil || response.StatusCode == http.StatusNotFound || c.regionalEndpoint == "" {
				return response, rerr
			}
			// Hack: retry the regional ARM endpoint in case of ARM traffic split and arm resource group replication is too slow
			bodyBytes, _ := ioutil.ReadAll(response.Body)
			defer func() {
				response.Body = ioutil.NopCloser(bytes.NewBuffer(bodyBytes))
			}()

			bodyString := string(bodyBytes)
			var body map[string]interface{}
			if e := json.Unmarshal(bodyBytes, &body); e != nil {
				klog.Errorf("Send.sendRequest: error in parsing response body string: %s, Skip retrying regional host", e.Error())
				return response, rerr
			}
			klog.V(5).Infof("Send.sendRequest original response: %s", bodyString)

			if err, ok := body["error"].(map[string]interface{}); !ok ||
				err["code"] == nil ||
				!strings.EqualFold(err["code"].(string), "ResourceGroupNotFound") {
				klog.V(5).Infof("Send.sendRequest: response body does not contain ResourceGroupNotFound error code. Skip retrying regional host")
				return response, rerr
			}

			currentHost := request.URL.Host
			if request.Host != "" {
				currentHost = request.Host
			}

			if strings.HasPrefix(strings.ToLower(currentHost), c.regionalEndpoint) {
				klog.V(5).Infof("Send.sendRequest: current host %s is regional host. Skip retrying regional host.", html.EscapeString(currentHost))
				return response, rerr
			}

			request.Host = c.regionalEndpoint
			request.URL.Host = c.regionalEndpoint
			klog.V(5).Infof("Send.sendRegionalRequest on ResourceGroupNotFound error. Retrying regional host: %s", html.EscapeString(request.Host))

			regionalResponse, regionalError := s.Do(request)
			// only use the result if the regional request actually goes through and returns 2xx status code, for two reasons:
			// 1. the retry on regional ARM host approach is a hack.
			// 2. the concatenated regional uri could be wrong as the rule is not officially declared by ARM.
			if regionalResponse == nil || regionalResponse.StatusCode > 299 {
				regionalErrStr := ""
				if regionalError != nil {
					regionalErrStr = regionalError.Error()
				}

				klog.V(5).Infof("Send.sendRegionalRequest failed to get response from regional host, error: '%s'. Ignoring the result.", regionalErrStr)
				return response, rerr
			}
			return regionalResponse, regionalError
		})
	}
}

// Send sends a http request to ARM service with possible retry to regional ARM endpoint.
func (c *Client) Send(ctx context.Context, request *http.Request, decorators ...autorest.SendDecorator) (*http.Response, *retry.Error) {
	response, err := autorest.SendWithSender(
		c.client,
		request,
		decorators...,
	)

	if response == nil && err == nil {
		return response, retry.NewError(false, fmt.Errorf("Empty response and no HTTP code"))
	}

	return response, retry.GetError(response, err)
}

func dumpRequest(req *http.Request, v klog.Level) {
	requestDump, err := httputil.DumpRequest(req, true)
	if err != nil {
		klog.Errorf("Failed to dump request: %v", err)
	} else {
		klog.V(v).Infof("Dumping request: %s", string(requestDump))
	}
}

// PreparePutRequest prepares put request
func (c *Client) PreparePutRequest(ctx context.Context, decorators ...autorest.PrepareDecorator) (*http.Request, error) {
	decorators = append(
		[]autorest.PrepareDecorator{
			autorest.AsContentType("application/json; charset=utf-8"),
			autorest.AsPut(),
			autorest.WithBaseURL(c.baseURI)},
		decorators...)
	return c.prepareRequest(ctx, decorators...)
}

// PreparePatchRequest prepares patch request
func (c *Client) PreparePatchRequest(ctx context.Context, decorators ...autorest.PrepareDecorator) (*http.Request, error) {
	decorators = append(
		[]autorest.PrepareDecorator{
			autorest.AsContentType("application/json; charset=utf-8"),
			autorest.AsPatch(),
			autorest.WithBaseURL(c.baseURI)},
		decorators...)
	return c.prepareRequest(ctx, decorators...)
}

// PreparePostRequest prepares post request
func (c *Client) PreparePostRequest(ctx context.Context, decorators ...autorest.PrepareDecorator) (*http.Request, error) {
	decorators = append(
		[]autorest.PrepareDecorator{
			autorest.AsContentType("application/json; charset=utf-8"),
			autorest.AsPost(),
			autorest.WithBaseURL(c.baseURI)},
		decorators...)
	return c.prepareRequest(ctx, decorators...)
}

// PrepareGetRequest prepares get request
func (c *Client) PrepareGetRequest(ctx context.Context, decorators ...autorest.PrepareDecorator) (*http.Request, error) {
	decorators = append(
		[]autorest.PrepareDecorator{
			autorest.AsGet(),
			autorest.WithBaseURL(c.baseURI)},
		decorators...)
	return c.prepareRequest(ctx, decorators...)
}

// PrepareDeleteRequest preparse delete request
func (c *Client) PrepareDeleteRequest(ctx context.Context, decorators ...autorest.PrepareDecorator) (*http.Request, error) {
	decorators = append(
		[]autorest.PrepareDecorator{
			autorest.AsDelete(),
			autorest.WithBaseURL(c.baseURI)},
		decorators...)
	return c.prepareRequest(ctx, decorators...)
}

// PrepareHeadRequest prepares head request
func (c *Client) PrepareHeadRequest(ctx context.Context, decorators ...autorest.PrepareDecorator) (*http.Request, error) {
	decorators = append(
		[]autorest.PrepareDecorator{
			autorest.AsHead(),
			autorest.WithBaseURL(c.baseURI)},
		decorators...)
	return c.prepareRequest(ctx, decorators...)
}

// WaitForAsyncOperationCompletion waits for an operation completion
func (c *Client) WaitForAsyncOperationCompletion(ctx context.Context, future *azure.Future, asyncOperationName string) error {
	err := future.WaitForCompletionRef(ctx, c.client)
	if err != nil {
		klog.V(5).Infof("Received error in WaitForCompletionRef: '%v'", err)
		return err
	}

	var done bool
	done, err = future.DoneWithContext(ctx, c.client)
	if err != nil {
		klog.V(5).Infof("Received error in DoneWithContext: '%v'", err)
		return autorest.NewErrorWithError(err, asyncOperationName, "Result", future.Response(), "Polling failure")
	}
	if !done {
		return azure.NewAsyncOpIncompleteError(asyncOperationName)
	}

	return nil
}

// WaitForAsyncOperationResult waits for an operation result.
func (c *Client) WaitForAsyncOperationResult(ctx context.Context, future *azure.Future, asyncOperationName string) (*http.Response, error) {
	err := c.WaitForAsyncOperationCompletion(ctx, future, asyncOperationName)
	if err != nil {
		klog.V(5).Infof("Received error in WaitForAsyncOperationCompletion: '%v'", err)
		return nil, err
	}
	return future.GetResult(c.client)
}

// SendAsync send a request and return a future object representing the async result as well as the origin http response
func (c *Client) SendAsync(ctx context.Context, request *http.Request) (*azure.Future, *http.Response, *retry.Error) {
	asyncResponse, rerr := c.Send(ctx, request)
	if rerr != nil {
		klog.V(5).Infof("Received error in %s: resourceID: %s, error: %s", "sendAsync.send", request.URL.String(), rerr.Error())
		return nil, nil, rerr
	}

	future, err := azure.NewFutureFromResponse(asyncResponse)
	if err != nil {
		klog.V(5).Infof("Received error in %s: resourceID: %s, error: %s", "sendAsync.respond", request.URL.String(), err)
		return nil, asyncResponse, retry.GetError(asyncResponse, err)
	}

	return &future, asyncResponse, nil
}

// GetResource get a resource by resource ID
func (c *Client) GetResourceWithExpandQuery(ctx context.Context, resourceID, expand string) (*http.Response, *retry.Error) {
	var decorators []autorest.PrepareDecorator
	if expand != "" {
		queryParameters := map[string]interface{}{
			"$expand": autorest.Encode("query", expand),
		}
		decorators = append(decorators, autorest.WithQueryParameters(queryParameters))
	}
	return c.GetResource(ctx, resourceID, decorators...)
}

// GetResourceWithDecorators get a resource with decorators by resource ID
func (c *Client) GetResource(ctx context.Context, resourceID string, decorators ...autorest.PrepareDecorator) (*http.Response, *retry.Error) {
	getDecorators := append([]autorest.PrepareDecorator{
		autorest.WithPathParameters("{resourceID}", map[string]interface{}{"resourceID": resourceID}),
	}, decorators...)
	request, err := c.PrepareGetRequest(ctx, getDecorators...)
	if err != nil {
		klog.V(5).Infof("Received error in %s: resourceID: %s, error: %s", "get.prepare", resourceID, err)
		return nil, retry.NewError(false, err)
	}

	return c.Send(ctx, request)
}

// PutResource puts a resource by resource ID
func (c *Client) PutResource(ctx context.Context, resourceID string, parameters interface{}) (*http.Response, *retry.Error) {
	putDecorators := []autorest.PrepareDecorator{
		autorest.WithPathParameters("{resourceID}", map[string]interface{}{"resourceID": resourceID}),
		autorest.WithJSON(parameters),
	}
	return c.PutResourceWithDecorators(ctx, resourceID, parameters, putDecorators)
}

func (c *Client) waitAsync(ctx context.Context, futures map[string]*azure.Future, previousResponses map[string]*PutResourcesResponse) {
	wg := sync.WaitGroup{}
	var responseLock sync.Mutex
	for resourceID, future := range futures {
		wg.Add(1)
		go func(resourceID string, future *azure.Future) {
			defer wg.Done()
			response, err := c.WaitForAsyncOperationResult(ctx, future, "armclient.PutResource")
			if err != nil {
				if response != nil {
					klog.V(5).Infof("Received error in WaitForAsyncOperationResult: '%s', response code %d", err.Error(), response.StatusCode)
				} else {
					klog.V(5).Infof("Received error in WaitForAsyncOperationResult: '%s', no response", err.Error())
				}

				retriableErr := retry.GetError(response, err)
				if !retriableErr.Retriable &&
					strings.Contains(strings.ToUpper(err.Error()), strings.ToUpper("InternalServerError")) {
					klog.V(5).Infof("Received InternalServerError in WaitForAsyncOperationResult: '%s', setting error retriable", err.Error())
					retriableErr.Retriable = true
				}

				responseLock.Lock()
				previousResponses[resourceID] = &PutResourcesResponse{
					Error: retriableErr,
				}
				responseLock.Unlock()
				return
			}
		}(resourceID, future)
	}
	wg.Wait()
}

// PutResources puts a list of resources from resources map[resourceID]parameters.
// Those resources sync requests are sequential while async requests are concurrent. It's especially
// useful when the ARM API doesn't support concurrent requests.
func (c *Client) PutResources(ctx context.Context, resources map[string]interface{}) map[string]*PutResourcesResponse {
	if len(resources) == 0 {
		return nil
	}

	// Sequential sync requests.
	futures := make(map[string]*azure.Future)
	responses := make(map[string]*PutResourcesResponse)
	for resourceID, parameters := range resources {
		future, rerr := c.PutResourceAsync(ctx, resourceID, parameters)
		if rerr != nil {
			responses[resourceID] = &PutResourcesResponse{
				Error: rerr,
			}
			continue
		}
		futures[resourceID] = future
	}

	c.waitAsync(ctx, futures, responses)

	return responses
}

// PutResourcesInBatches is similar with PutResources, but it sends sync request concurrently in batches.
func (c *Client) PutResourcesInBatches(ctx context.Context, resources map[string]interface{}, batchSize int) map[string]*PutResourcesResponse {
	if len(resources) == 0 {
		return nil
	}

	if batchSize <= 0 {
		klog.V(4).Infof("PutResourcesInBatches: batch size %d, put resources in sequence", batchSize)
		return c.PutResources(ctx, resources)
	}

	if batchSize > len(resources) {
		klog.V(4).Infof("PutResourcesInBatches: batch size %d, but the number of the resources is %d", batchSize, resources)
		batchSize = len(resources)
	}
	klog.V(4).Infof("PutResourcesInBatches: send sync requests in parallel with the batch size %d", batchSize)

	// Convert map to slice because it is more straightforward to
	// loop over slice in batches than map.
	type resourcesMeta struct {
		resourceID string
		parameters interface{}
	}
	resourcesList := make([]resourcesMeta, 0)
	for resourceID, parameters := range resources {
		resourcesList = append(resourcesList, resourcesMeta{
			resourceID: resourceID,
			parameters: parameters,
		})
	}

	// Concurrent sync requests in batches.
	futures := make(map[string]*azure.Future)
	responses := make(map[string]*PutResourcesResponse)
	wg := sync.WaitGroup{}
	var responseLock, futuresLock sync.Mutex
	for i := 0; i < len(resourcesList); i += batchSize {
		j := i + batchSize
		if j > len(resourcesList) {
			j = len(resourcesList)
		}

		for k := i; k < j; k++ {
			wg.Add(1)
			go func(resourceID string, parameters interface{}) {
				defer wg.Done()
				future, rerr := c.PutResourceAsync(ctx, resourceID, parameters)
				if rerr != nil {
					responseLock.Lock()
					responses[resourceID] = &PutResourcesResponse{
						Error: rerr,
					}
					responseLock.Unlock()
					return
				}

				futuresLock.Lock()
				futures[resourceID] = future
				futuresLock.Unlock()
			}(resourcesList[k].resourceID, resourcesList[k].parameters)
		}
		wg.Wait()
	}

	// Concurrent async requests.
	c.waitAsync(ctx, futures, responses)

	return responses
}

// PutResourceWithDecorators puts a resource by resource ID
func (c *Client) PutResourceWithDecorators(ctx context.Context, resourceID string, parameters interface{}, decorators []autorest.PrepareDecorator) (*http.Response, *retry.Error) {
	request, err := c.PreparePutRequest(ctx, decorators...)
	if err != nil {
		klog.V(5).Infof("Received error in %s: resourceID: %s, error: %s", "put.prepare", resourceID, err)
		return nil, retry.NewError(false, err)
	}
	dumpRequest(request, 10)

	future, resp, clientErr := c.SendAsync(ctx, request)
	defer c.CloseResponse(ctx, resp)
	if clientErr != nil {
		klog.V(5).Infof("Received error in %s: resourceID: %s, error: %s", "put.send", resourceID, clientErr.Error())
		return nil, clientErr
	}

	response, err := c.WaitForAsyncOperationResult(ctx, future, "armclient.PutResource")
	if err != nil {
		if response != nil {
			klog.V(5).Infof("Received error in WaitForAsyncOperationResult: '%s', response code %d", err.Error(), response.StatusCode)
		} else {
			klog.V(5).Infof("Received error in WaitForAsyncOperationResult: '%s', no response", err.Error())
		}

		retriableErr := retry.GetError(response, err)
		if !retriableErr.Retriable &&
			strings.Contains(strings.ToUpper(err.Error()), strings.ToUpper("InternalServerError")) {
			klog.V(5).Infof("Received InternalServerError in WaitForAsyncOperationResult: '%s', setting error retriable", err.Error())
			retriableErr.Retriable = true
		}
		return nil, retriableErr
	}

	return response, nil
}

// PatchResource patches a resource by resource ID
func (c *Client) PatchResource(ctx context.Context, resourceID string, parameters interface{}) (*http.Response, *retry.Error) {
	decorators := []autorest.PrepareDecorator{
		autorest.WithPathParameters("{resourceID}", map[string]interface{}{"resourceID": resourceID}),
		autorest.WithJSON(parameters),
	}

	request, err := c.PreparePatchRequest(ctx, decorators...)
	if err != nil {
		klog.V(5).Infof("Received error in %s: resourceID: %s, error: %s", "patch.prepare", resourceID, err)
		return nil, retry.NewError(false, err)
	}

	future, resp, clientErr := c.SendAsync(ctx, request)
	defer c.CloseResponse(ctx, resp)
	if clientErr != nil {
		klog.V(5).Infof("Received error in %s: resourceID: %s, error: %s", "patch.send", resourceID, clientErr.Error())
		return nil, clientErr
	}

	response, err := c.WaitForAsyncOperationResult(ctx, future, "armclient.PatchResource")
	if err != nil {
		if response != nil {
			klog.V(5).Infof("Received error in WaitForAsyncOperationResult: '%s', response code %d", err.Error(), response.StatusCode)
		} else {
			klog.V(5).Infof("Received error in WaitForAsyncOperationResult: '%s', no response", err.Error())
		}

		retriableErr := retry.GetError(response, err)
		if !retriableErr.Retriable &&
			strings.Contains(strings.ToUpper(err.Error()), strings.ToUpper("InternalServerError")) {
			klog.V(5).Infof("Received InternalServerError in WaitForAsyncOperationResult: '%s', setting error retriable", err.Error())
			retriableErr.Retriable = true
		}
		return nil, retriableErr
	}

	return response, nil
}

// PatchResourceAsync patches a resource by resource ID asynchronously
func (c *Client) PatchResourceAsync(ctx context.Context, resourceID string, parameters interface{}) (*azure.Future, *retry.Error) {
	decorators := []autorest.PrepareDecorator{
		autorest.WithPathParameters("{resourceID}", map[string]interface{}{"resourceID": resourceID}),
		autorest.WithJSON(parameters),
	}

	request, err := c.PreparePatchRequest(ctx, decorators...)
	if err != nil {
		klog.V(5).Infof("Received error in %s: resourceID: %s, error: %s", "patch.prepare", resourceID, err)
		return nil, retry.NewError(false, err)
	}

	future, resp, clientErr := c.SendAsync(ctx, request)
	defer c.CloseResponse(ctx, resp)
	if clientErr != nil {
		klog.V(5).Infof("Received error in %s: resourceID: %s, error: %s", "patch.send", resourceID, clientErr.Error())
		return nil, clientErr
	}
	return future, clientErr
}

// PutResourceAsync puts a resource by resource ID in async mode
func (c *Client) PutResourceAsync(ctx context.Context, resourceID string, parameters interface{}) (*azure.Future, *retry.Error) {
	decorators := []autorest.PrepareDecorator{
		autorest.WithPathParameters("{resourceID}", map[string]interface{}{"resourceID": resourceID}),
		autorest.WithJSON(parameters),
	}

	request, err := c.PreparePutRequest(ctx, decorators...)
	if err != nil {
		klog.V(5).Infof("Received error in %s: resourceID: %s, error: %s", "put.prepare", resourceID, err)
		return nil, retry.NewError(false, err)
	}
	dumpRequest(request, 10)

	future, resp, rErr := c.SendAsync(ctx, request)
	defer c.CloseResponse(ctx, resp)
	if rErr != nil {
		klog.V(5).Infof("Received error in %s: resourceID: %s, error: %s", "put.send", resourceID, err)
		return nil, rErr
	}

	return future, nil
}

// PostResource posts a resource by resource ID
func (c *Client) PostResource(ctx context.Context, resourceID, action string, parameters interface{}, queryParameters map[string]interface{}) (*http.Response, *retry.Error) {
	pathParameters := map[string]interface{}{
		"resourceID": resourceID,
		"action":     action,
	}

	decorators := []autorest.PrepareDecorator{
		autorest.WithPathParameters("{resourceID}/{action}", pathParameters),
		autorest.WithJSON(parameters),
	}
	if len(queryParameters) > 0 {
		decorators = append(decorators, autorest.WithQueryParameters(queryParameters))
	}

	request, err := c.PreparePostRequest(ctx, decorators...)
	if err != nil {
		klog.V(5).Infof("Received error in %s: resourceID: %s, error: %s", "post.prepare", resourceID, err)
		return nil, retry.NewError(false, err)
	}

	return c.Send(ctx, request)
}

// DeleteResource deletes a resource by resource ID
func (c *Client) DeleteResource(ctx context.Context, resourceID, ifMatch string) *retry.Error {
	future, clientErr := c.DeleteResourceAsync(ctx, resourceID, ifMatch)
	if clientErr != nil {
		klog.V(5).Infof("Received error in %s: resourceID: %s, error: %s", "delete.request", resourceID, clientErr.Error())
		return clientErr
	}

	if future == nil {
		return nil
	}

	if err := c.WaitForAsyncOperationCompletion(ctx, future, "armclient.DeleteResource"); err != nil {
		klog.V(5).Infof("Received error in %s: resourceID: %s, error: %s", "delete.wait", resourceID, clientErr.Error())
		return retry.NewError(true, err)
	}

	return nil
}

// HeadResource heads a resource by resource ID
func (c *Client) HeadResource(ctx context.Context, resourceID string) (*http.Response, *retry.Error) {
	decorators := []autorest.PrepareDecorator{
		autorest.WithPathParameters("{resourceID}", map[string]interface{}{"resourceID": resourceID}),
	}
	request, err := c.PrepareHeadRequest(ctx, decorators...)
	if err != nil {
		klog.V(5).Infof("Received error in %s: resourceID: %s, error: %s", "head.prepare", resourceID, err)
		return nil, retry.NewError(false, err)
	}

	return c.Send(ctx, request)
}

// DeleteResourceAsync delete a resource by resource ID and returns a future representing the async result
func (c *Client) DeleteResourceAsync(ctx context.Context, resourceID, ifMatch string) (*azure.Future, *retry.Error) {
	decorators := []autorest.PrepareDecorator{
		autorest.WithPathParameters("{resourceID}", map[string]interface{}{"resourceID": resourceID}),
	}
	if len(ifMatch) > 0 {
		decorators = append(decorators, autorest.WithHeader("If-Match", autorest.String(ifMatch)))
	}

	deleteRequest, err := c.PrepareDeleteRequest(ctx, decorators...)
	if err != nil {
		klog.V(5).Infof("Received error in %s: resourceID: %s, error: %s", "deleteAsync.prepare", resourceID, err)
		return nil, retry.NewError(false, err)
	}

	resp, rerr := c.Send(ctx, deleteRequest)
	defer c.CloseResponse(ctx, resp)
	if rerr != nil {
		klog.V(5).Infof("Received error in %s: resourceID: %s, error: %s", "deleteAsync.send", resourceID, rerr.Error())
		return nil, rerr
	}

	err = autorest.Respond(
		resp,
		azure.WithErrorUnlessStatusCode(http.StatusOK, http.StatusAccepted, http.StatusNoContent, http.StatusNotFound))
	if err != nil {
		klog.V(5).Infof("Received error in %s: resourceID: %s, error: %s", "deleteAsync.respond", resourceID, err)
		return nil, retry.GetError(resp, err)
	}

	if resp.StatusCode == http.StatusNotFound {
		return nil, nil
	}

	future, err := azure.NewFutureFromResponse(resp)
	if err != nil {
		klog.V(5).Infof("Received error in %s: resourceID: %s, error: %s", "deleteAsync.future", resourceID, err)
		return nil, retry.GetError(resp, err)
	}

	return &future, nil
}

// CloseResponse closes a response
func (c *Client) CloseResponse(ctx context.Context, response *http.Response) {
	if response != nil && response.Body != nil {
		if err := response.Body.Close(); err != nil {
			klog.Errorf("Error closing the response body: %v", err)
		}
	}
}

func (c *Client) prepareRequest(ctx context.Context, decorators ...autorest.PrepareDecorator) (*http.Request, error) {
	decorators = append(
		decorators,
		withAPIVersion(c.apiVersion))
	preparer := autorest.CreatePreparer(decorators...)
	return preparer.Prepare((&http.Request{}).WithContext(ctx))
}

func withAPIVersion(apiVersion string) autorest.PrepareDecorator {
	const apiVersionKey = "api-version"
	return func(p autorest.Preparer) autorest.Preparer {
		return autorest.PreparerFunc(func(r *http.Request) (*http.Request, error) {
			r, err := p.Prepare(r)
			if err == nil {
				if r.URL == nil {
					return r, fmt.Errorf("Error in withAPIVersion: Invoked with a nil URL")
				}

				v := r.URL.Query()
				if len(v.Get(apiVersionKey)) > 0 {
					return r, nil
				}

				v.Add(apiVersionKey, apiVersion)
				r.URL.RawQuery = v.Encode()
			}
			return r, err
		})
	}
}

// GetResourceID gets Azure resource ID
func GetResourceID(subscriptionID, resourceGroupName, resourceType, resourceName string) string {
	return fmt.Sprintf("/subscriptions/%s/resourceGroups/%s/providers/%s/%s",
		autorest.Encode("path", subscriptionID),
		autorest.Encode("path", resourceGroupName),
		resourceType,
		autorest.Encode("path", resourceName))
}

// GetChildResourceID gets Azure child resource ID
func GetChildResourceID(subscriptionID, resourceGroupName, resourceType, resourceName, childResourceType, childResourceName string) string {
	return fmt.Sprintf("/subscriptions/%s/resourceGroups/%s/providers/%s/%s/%s/%s",
		autorest.Encode("path", subscriptionID),
		autorest.Encode("path", resourceGroupName),
		resourceType,
		autorest.Encode("path", resourceName),
		childResourceType,
		autorest.Encode("path", childResourceName))
}

// GetChildResourcesListID gets Azure child resources list ID
func GetChildResourcesListID(subscriptionID, resourceGroupName, resourceType, resourceName, childResourceType string) string {
	return fmt.Sprintf("/subscriptions/%s/resourceGroups/%s/providers/%s/%s/%s",
		autorest.Encode("path", subscriptionID),
		autorest.Encode("path", resourceGroupName),
		resourceType,
		autorest.Encode("path", resourceName),
		childResourceType)
}

// GetProviderResourceID gets Azure RP resource ID
func GetProviderResourceID(subscriptionID, providerNamespace string) string {
	return fmt.Sprintf("/subscriptions/%s/providers/%s",
		autorest.Encode("path", subscriptionID),
		providerNamespace)
}

// GetProviderResourcesListID gets Azure RP resources list ID
func GetProviderResourcesListID(subscriptionID string) string {
	return fmt.Sprintf("/subscriptions/%s/providers", autorest.Encode("path", subscriptionID))
}