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// Package storage provides clients for Microsoft Azure Storage Services.
package storage
import (
"bufio"
"bytes"
"encoding/base64"
"encoding/json"
"encoding/xml"
"errors"
"fmt"
"io"
"io/ioutil"
"mime"
"mime/multipart"
"net/http"
"net/url"
"regexp"
"runtime"
"strings"
"time"
"github.com/Azure/go-autorest/autorest"
"github.com/Azure/go-autorest/autorest/azure"
)
const (
// DefaultBaseURL is the domain name used for storage requests in the
// public cloud when a default client is created.
DefaultBaseURL = "core.windows.net"
// DefaultAPIVersion is the Azure Storage API version string used when a
// basic client is created.
DefaultAPIVersion = "2016-05-31"
defaultUseHTTPS = true
// StorageEmulatorAccountName is the fixed storage account used by Azure Storage Emulator
StorageEmulatorAccountName = "devstoreaccount1"
// StorageEmulatorAccountKey is the the fixed storage account used by Azure Storage Emulator
StorageEmulatorAccountKey = "Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw=="
blobServiceName = "blob"
tableServiceName = "table"
queueServiceName = "queue"
fileServiceName = "file"
storageEmulatorBlob = "127.0.0.1:10000"
storageEmulatorTable = "127.0.0.1:10002"
storageEmulatorQueue = "127.0.0.1:10001"
userAgentHeader = "User-Agent"
userDefinedMetadataHeaderPrefix = "x-ms-meta-"
)
var (
validStorageAccount = regexp.MustCompile("^[0-9a-z]{3,24}$")
)
// Sender sends a request
type Sender interface {
Send(*Client, *http.Request) (*http.Response, error)
}
// DefaultSender is the default sender for the client. It implements
// an automatic retry strategy.
type DefaultSender struct {
RetryAttempts int
RetryDuration time.Duration
ValidStatusCodes []int
attempts int // used for testing
}
// Send is the default retry strategy in the client
func (ds *DefaultSender) Send(c *Client, req *http.Request) (resp *http.Response, err error) {
rr := autorest.NewRetriableRequest(req)
for attempts := 0; attempts < ds.RetryAttempts; attempts++ {
err = rr.Prepare()
if err != nil {
return resp, err
}
resp, err = c.HTTPClient.Do(rr.Request())
if err != nil || !autorest.ResponseHasStatusCode(resp, ds.ValidStatusCodes...) {
return resp, err
}
autorest.DelayForBackoff(ds.RetryDuration, attempts, req.Cancel)
ds.attempts = attempts
}
ds.attempts++
return resp, err
}
// Client is the object that needs to be constructed to perform
// operations on the storage account.
type Client struct {
// HTTPClient is the http.Client used to initiate API
// requests. http.DefaultClient is used when creating a
// client.
HTTPClient *http.Client
// Sender is an interface that sends the request. Clients are
// created with a DefaultSender. The DefaultSender has an
// automatic retry strategy built in. The Sender can be customized.
Sender Sender
accountName string
accountKey []byte
useHTTPS bool
UseSharedKeyLite bool
baseURL string
apiVersion string
userAgent string
}
type storageResponse struct {
statusCode int
headers http.Header
body io.ReadCloser
}
type odataResponse struct {
storageResponse
odata odataErrorWrapper
}
// AzureStorageServiceError contains fields of the error response from
// Azure Storage Service REST API. See https://msdn.microsoft.com/en-us/library/azure/dd179382.aspx
// Some fields might be specific to certain calls.
type AzureStorageServiceError struct {
Code string `xml:"Code"`
Message string `xml:"Message"`
AuthenticationErrorDetail string `xml:"AuthenticationErrorDetail"`
QueryParameterName string `xml:"QueryParameterName"`
QueryParameterValue string `xml:"QueryParameterValue"`
Reason string `xml:"Reason"`
Lang string
StatusCode int
RequestID string
Date string
APIVersion string
}
type odataErrorMessage struct {
Lang string `json:"lang"`
Value string `json:"value"`
}
type odataError struct {
Code string `json:"code"`
Message odataErrorMessage `json:"message"`
}
type odataErrorWrapper struct {
Err odataError `json:"odata.error"`
}
// UnexpectedStatusCodeError is returned when a storage service responds with neither an error
// nor with an HTTP status code indicating success.
type UnexpectedStatusCodeError struct {
allowed []int
got int
}
func (e UnexpectedStatusCodeError) Error() string {
s := func(i int) string { return fmt.Sprintf("%d %s", i, http.StatusText(i)) }
got := s(e.got)
expected := []string{}
for _, v := range e.allowed {
expected = append(expected, s(v))
}
return fmt.Sprintf("storage: status code from service response is %s; was expecting %s", got, strings.Join(expected, " or "))
}
// Got is the actual status code returned by Azure.
func (e UnexpectedStatusCodeError) Got() int {
return e.got
}
// NewBasicClient constructs a Client with given storage service name and
// key.
func NewBasicClient(accountName, accountKey string) (Client, error) {
if accountName == StorageEmulatorAccountName {
return NewEmulatorClient()
}
return NewClient(accountName, accountKey, DefaultBaseURL, DefaultAPIVersion, defaultUseHTTPS)
}
// NewBasicClientOnSovereignCloud constructs a Client with given storage service name and
// key in the referenced cloud.
func NewBasicClientOnSovereignCloud(accountName, accountKey string, env azure.Environment) (Client, error) {
if accountName == StorageEmulatorAccountName {
return NewEmulatorClient()
}
return NewClient(accountName, accountKey, env.StorageEndpointSuffix, DefaultAPIVersion, defaultUseHTTPS)
}
//NewEmulatorClient contructs a Client intended to only work with Azure
//Storage Emulator
func NewEmulatorClient() (Client, error) {
return NewClient(StorageEmulatorAccountName, StorageEmulatorAccountKey, DefaultBaseURL, DefaultAPIVersion, false)
}
// NewClient constructs a Client. This should be used if the caller wants
// to specify whether to use HTTPS, a specific REST API version or a custom
// storage endpoint than Azure Public Cloud.
func NewClient(accountName, accountKey, blobServiceBaseURL, apiVersion string, useHTTPS bool) (Client, error) {
var c Client
if !IsValidStorageAccount(accountName) {
return c, fmt.Errorf("azure: account name is not valid: it must be between 3 and 24 characters, and only may contain numbers and lowercase letters: %v", accountName)
} else if accountKey == "" {
return c, fmt.Errorf("azure: account key required")
} else if blobServiceBaseURL == "" {
return c, fmt.Errorf("azure: base storage service url required")
}
key, err := base64.StdEncoding.DecodeString(accountKey)
if err != nil {
return c, fmt.Errorf("azure: malformed storage account key: %v", err)
}
c = Client{
HTTPClient: http.DefaultClient,
accountName: accountName,
accountKey: key,
useHTTPS: useHTTPS,
baseURL: blobServiceBaseURL,
apiVersion: apiVersion,
UseSharedKeyLite: false,
Sender: &DefaultSender{
RetryAttempts: 5,
ValidStatusCodes: []int{
http.StatusRequestTimeout, // 408
http.StatusInternalServerError, // 500
http.StatusBadGateway, // 502
http.StatusServiceUnavailable, // 503
http.StatusGatewayTimeout, // 504
},
RetryDuration: time.Second * 5,
},
}
c.userAgent = c.getDefaultUserAgent()
return c, nil
}
// IsValidStorageAccount checks if the storage account name is valid.
// See https://docs.microsoft.com/en-us/azure/storage/storage-create-storage-account
func IsValidStorageAccount(account string) bool {
return validStorageAccount.MatchString(account)
}
func (c Client) getDefaultUserAgent() string {
return fmt.Sprintf("Go/%s (%s-%s) azure-storage-go/%s api-version/%s",
runtime.Version(),
runtime.GOARCH,
runtime.GOOS,
sdkVersion,
c.apiVersion,
)
}
// 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)
}
// protectUserAgent is used in funcs that include extraheaders as a parameter.
// It prevents the User-Agent header to be overwritten, instead if it happens to
// be present, it gets added to the current User-Agent. Use it before getStandardHeaders
func (c *Client) protectUserAgent(extraheaders map[string]string) map[string]string {
if v, ok := extraheaders[userAgentHeader]; ok {
c.AddToUserAgent(v)
delete(extraheaders, userAgentHeader)
}
return extraheaders
}
func (c Client) getBaseURL(service string) *url.URL {
scheme := "http"
if c.useHTTPS {
scheme = "https"
}
host := ""
if c.accountName == StorageEmulatorAccountName {
switch service {
case blobServiceName:
host = storageEmulatorBlob
case tableServiceName:
host = storageEmulatorTable
case queueServiceName:
host = storageEmulatorQueue
}
} else {
host = fmt.Sprintf("%s.%s.%s", c.accountName, service, c.baseURL)
}
return &url.URL{
Scheme: scheme,
Host: host,
}
}
func (c Client) getEndpoint(service, path string, params url.Values) string {
u := c.getBaseURL(service)
// API doesn't accept path segments not starting with '/'
if !strings.HasPrefix(path, "/") {
path = fmt.Sprintf("/%v", path)
}
if c.accountName == StorageEmulatorAccountName {
path = fmt.Sprintf("/%v%v", StorageEmulatorAccountName, path)
}
u.Path = path
u.RawQuery = params.Encode()
return u.String()
}
// GetBlobService returns a BlobStorageClient which can operate on the blob
// service of the storage account.
func (c Client) GetBlobService() BlobStorageClient {
b := BlobStorageClient{
client: c,
}
b.client.AddToUserAgent(blobServiceName)
b.auth = sharedKey
if c.UseSharedKeyLite {
b.auth = sharedKeyLite
}
return b
}
// GetQueueService returns a QueueServiceClient which can operate on the queue
// service of the storage account.
func (c Client) GetQueueService() QueueServiceClient {
q := QueueServiceClient{
client: c,
}
q.client.AddToUserAgent(queueServiceName)
q.auth = sharedKey
if c.UseSharedKeyLite {
q.auth = sharedKeyLite
}
return q
}
// GetTableService returns a TableServiceClient which can operate on the table
// service of the storage account.
func (c Client) GetTableService() TableServiceClient {
t := TableServiceClient{
client: c,
}
t.client.AddToUserAgent(tableServiceName)
t.auth = sharedKeyForTable
if c.UseSharedKeyLite {
t.auth = sharedKeyLiteForTable
}
return t
}
// GetFileService returns a FileServiceClient which can operate on the file
// service of the storage account.
func (c Client) GetFileService() FileServiceClient {
f := FileServiceClient{
client: c,
}
f.client.AddToUserAgent(fileServiceName)
f.auth = sharedKey
if c.UseSharedKeyLite {
f.auth = sharedKeyLite
}
return f
}
func (c Client) getStandardHeaders() map[string]string {
return map[string]string{
userAgentHeader: c.userAgent,
"x-ms-version": c.apiVersion,
"x-ms-date": currentTimeRfc1123Formatted(),
}
}
func (c Client) exec(verb, url string, headers map[string]string, body io.Reader, auth authentication) (*storageResponse, error) {
headers, err := c.addAuthorizationHeader(verb, url, headers, auth)
if err != nil {
return nil, err
}
req, err := http.NewRequest(verb, url, body)
if err != nil {
return nil, errors.New("azure/storage: error creating request: " + err.Error())
}
// if a body was provided ensure that the content length was set.
// http.NewRequest() will automatically do this for a handful of types
// and for those that it doesn't we will handle here.
if body != nil && req.ContentLength < 1 {
if lr, ok := body.(*io.LimitedReader); ok {
setContentLengthFromLimitedReader(req, lr)
}
}
for k, v := range headers {
req.Header[k] = append(req.Header[k], v) // Must bypass case munging present in `Add` by using map functions directly. See https://github.com/Azure/azure-sdk-for-go/issues/645
}
resp, err := c.Sender.Send(&c, req)
if err != nil {
return nil, err
}
if resp.StatusCode >= 400 && resp.StatusCode <= 505 {
var respBody []byte
respBody, err = readAndCloseBody(resp.Body)
if err != nil {
return nil, err
}
requestID, date, version := getDebugHeaders(resp.Header)
if len(respBody) == 0 {
// no error in response body, might happen in HEAD requests
err = serviceErrFromStatusCode(resp.StatusCode, resp.Status, requestID, date, version)
} else {
storageErr := AzureStorageServiceError{
StatusCode: resp.StatusCode,
RequestID: requestID,
Date: date,
APIVersion: version,
}
// response contains storage service error object, unmarshal
if resp.Header.Get("Content-Type") == "application/xml" {
errIn := serviceErrFromXML(respBody, &storageErr)
if err != nil { // error unmarshaling the error response
err = errIn
}
} else {
errIn := serviceErrFromJSON(respBody, &storageErr)
if err != nil { // error unmarshaling the error response
err = errIn
}
}
err = storageErr
}
return &storageResponse{
statusCode: resp.StatusCode,
headers: resp.Header,
body: ioutil.NopCloser(bytes.NewReader(respBody)), /* restore the body */
}, err
}
return &storageResponse{
statusCode: resp.StatusCode,
headers: resp.Header,
body: resp.Body}, nil
}
func (c Client) execInternalJSONCommon(verb, url string, headers map[string]string, body io.Reader, auth authentication) (*odataResponse, *http.Request, *http.Response, error) {
headers, err := c.addAuthorizationHeader(verb, url, headers, auth)
if err != nil {
return nil, nil, nil, err
}
req, err := http.NewRequest(verb, url, body)
for k, v := range headers {
req.Header.Add(k, v)
}
resp, err := c.Sender.Send(&c, req)
if err != nil {
return nil, nil, nil, err
}
respToRet := &odataResponse{}
respToRet.body = resp.Body
respToRet.statusCode = resp.StatusCode
respToRet.headers = resp.Header
statusCode := resp.StatusCode
if statusCode >= 400 && statusCode <= 505 {
var respBody []byte
respBody, err = readAndCloseBody(resp.Body)
if err != nil {
return nil, nil, nil, err
}
requestID, date, version := getDebugHeaders(resp.Header)
if len(respBody) == 0 {
// no error in response body, might happen in HEAD requests
err = serviceErrFromStatusCode(resp.StatusCode, resp.Status, requestID, date, version)
return respToRet, req, resp, err
}
// try unmarshal as odata.error json
err = json.Unmarshal(respBody, &respToRet.odata)
}
return respToRet, req, resp, err
}
func (c Client) execInternalJSON(verb, url string, headers map[string]string, body io.Reader, auth authentication) (*odataResponse, error) {
respToRet, _, _, err := c.execInternalJSONCommon(verb, url, headers, body, auth)
return respToRet, err
}
func (c Client) execBatchOperationJSON(verb, url string, headers map[string]string, body io.Reader, auth authentication) (*odataResponse, error) {
// execute common query, get back generated request, response etc... for more processing.
respToRet, req, resp, err := c.execInternalJSONCommon(verb, url, headers, body, auth)
if err != nil {
return nil, err
}
// return the OData in the case of executing batch commands.
// In this case we need to read the outer batch boundary and contents.
// Then we read the changeset information within the batch
var respBody []byte
respBody, err = readAndCloseBody(resp.Body)
if err != nil {
return nil, err
}
// outer multipart body
_, batchHeader, err := mime.ParseMediaType(resp.Header["Content-Type"][0])
if err != nil {
return nil, err
}
// batch details.
batchBoundary := batchHeader["boundary"]
batchPartBuf, changesetBoundary, err := genBatchReader(batchBoundary, respBody)
if err != nil {
return nil, err
}
// changeset details.
err = genChangesetReader(req, respToRet, batchPartBuf, changesetBoundary)
if err != nil {
return nil, err
}
return respToRet, nil
}
func genChangesetReader(req *http.Request, respToRet *odataResponse, batchPartBuf io.Reader, changesetBoundary string) error {
changesetMultiReader := multipart.NewReader(batchPartBuf, changesetBoundary)
changesetPart, err := changesetMultiReader.NextPart()
if err != nil {
return err
}
changesetPartBufioReader := bufio.NewReader(changesetPart)
changesetResp, err := http.ReadResponse(changesetPartBufioReader, req)
if err != nil {
return err
}
if changesetResp.StatusCode != http.StatusNoContent {
changesetBody, err := readAndCloseBody(changesetResp.Body)
err = json.Unmarshal(changesetBody, &respToRet.odata)
if err != nil {
return err
}
respToRet.statusCode = changesetResp.StatusCode
}
return nil
}
func genBatchReader(batchBoundary string, respBody []byte) (io.Reader, string, error) {
respBodyString := string(respBody)
respBodyReader := strings.NewReader(respBodyString)
// reading batchresponse
batchMultiReader := multipart.NewReader(respBodyReader, batchBoundary)
batchPart, err := batchMultiReader.NextPart()
if err != nil {
return nil, "", err
}
batchPartBufioReader := bufio.NewReader(batchPart)
_, changesetHeader, err := mime.ParseMediaType(batchPart.Header.Get("Content-Type"))
if err != nil {
return nil, "", err
}
changesetBoundary := changesetHeader["boundary"]
return batchPartBufioReader, changesetBoundary, nil
}
func readAndCloseBody(body io.ReadCloser) ([]byte, error) {
defer body.Close()
out, err := ioutil.ReadAll(body)
if err == io.EOF {
err = nil
}
return out, err
}
func serviceErrFromXML(body []byte, storageErr *AzureStorageServiceError) error {
if err := xml.Unmarshal(body, storageErr); err != nil {
storageErr.Message = fmt.Sprintf("Response body could no be unmarshaled: %v. Body: %v.", err, string(body))
return err
}
return nil
}
func serviceErrFromJSON(body []byte, storageErr *AzureStorageServiceError) error {
odataError := odataErrorWrapper{}
if err := json.Unmarshal(body, &odataError); err != nil {
storageErr.Message = fmt.Sprintf("Response body could no be unmarshaled: %v. Body: %v.", err, string(body))
return err
}
storageErr.Code = odataError.Err.Code
storageErr.Message = odataError.Err.Message.Value
storageErr.Lang = odataError.Err.Message.Lang
return nil
}
func serviceErrFromStatusCode(code int, status string, requestID, date, version string) AzureStorageServiceError {
return AzureStorageServiceError{
StatusCode: code,
Code: status,
RequestID: requestID,
Date: date,
APIVersion: version,
Message: "no response body was available for error status code",
}
}
func (e AzureStorageServiceError) Error() string {
return fmt.Sprintf("storage: service returned error: StatusCode=%d, ErrorCode=%s, ErrorMessage=%s, RequestInitiated=%s, RequestId=%s, API Version=%s, QueryParameterName=%s, QueryParameterValue=%s",
e.StatusCode, e.Code, e.Message, e.Date, e.RequestID, e.APIVersion, e.QueryParameterName, e.QueryParameterValue)
}
// checkRespCode returns UnexpectedStatusError if the given response code is not
// one of the allowed status codes; otherwise nil.
func checkRespCode(respCode int, allowed []int) error {
for _, v := range allowed {
if respCode == v {
return nil
}
}
return UnexpectedStatusCodeError{allowed, respCode}
}
func (c Client) addMetadataToHeaders(h map[string]string, metadata map[string]string) map[string]string {
metadata = c.protectUserAgent(metadata)
for k, v := range metadata {
h[userDefinedMetadataHeaderPrefix+k] = v
}
return h
}
func getDebugHeaders(h http.Header) (requestID, date, version string) {
requestID = h.Get("x-ms-request-id")
version = h.Get("x-ms-version")
date = h.Get("Date")
return
}
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