fix Context issue

Signed-off-by: Shawn Chen <chen8132@gmail.com>

vendor/github.com/denverdino/aliyungo/cdn/auth/random_uuid.go

@@ -0,0 +1,97 @@
+package auth
+
+import (
+	"crypto/rand"
+	"fmt"
+	"io"
+	"os"
+	"syscall"
+	"time"
+)
+
+const (
+	// Bits is the number of bits in a UUID
+	Bits = 128
+
+	// Size is the number of bytes in a UUID
+	Size = Bits / 8
+
+	format = "%08x%04x%04x%04x%012x"
+)
+
+var (
+	// Loggerf can be used to override the default logging destination. Such
+	// log messages in this library should be logged at warning or higher.
+	Loggerf = func(format string, args ...interface{}) {}
+)
+
+// UUID represents a UUID value. UUIDs can be compared and set to other values
+// and accessed by byte.
+type UUID [Size]byte
+
+// GenerateUUID creates a new, version 4 uuid.
+func GenerateUUID() (u UUID) {
+	const (
+		// ensures we backoff for less than 450ms total. Use the following to
+		// select new value, in units of 10ms:
+		// 	n*(n+1)/2 = d -> n^2 + n - 2d -> n = (sqrt(8d + 1) - 1)/2
+		maxretries = 9
+		backoff    = time.Millisecond * 10
+	)
+
+	var (
+		totalBackoff time.Duration
+		count        int
+		retries      int
+	)
+
+	for {
+		// This should never block but the read may fail. Because of this,
+		// we just try to read the random number generator until we get
+		// something. This is a very rare condition but may happen.
+		b := time.Duration(retries) * backoff
+		time.Sleep(b)
+		totalBackoff += b
+
+		n, err := io.ReadFull(rand.Reader, u[count:])
+		if err != nil {
+			if retryOnError(err) && retries < maxretries {
+				count += n
+				retries++
+				Loggerf("error generating version 4 uuid, retrying: %v", err)
+				continue
+			}
+
+			// Any other errors represent a system problem. What did someone
+			// do to /dev/urandom?
+			panic(fmt.Errorf("error reading random number generator, retried for %v: %v", totalBackoff.String(), err))
+		}
+
+		break
+	}
+
+	u[6] = (u[6] & 0x0f) | 0x40 // set version byte
+	u[8] = (u[8] & 0x3f) | 0x80 // set high order byte 0b10{8,9,a,b}
+
+	return u
+}
+
+func (u UUID) String() string {
+	return fmt.Sprintf(format, u[:4], u[4:6], u[6:8], u[8:10], u[10:])
+}
+
+// retryOnError tries to detect whether or not retrying would be fruitful.
+func retryOnError(err error) bool {
+	switch err := err.(type) {
+	case *os.PathError:
+		return retryOnError(err.Err) // unpack the target error
+	case syscall.Errno:
+		if err == syscall.EPERM {
+			// EPERM represents an entropy pool exhaustion, a condition under
+			// which we backoff and retry.
+			return true
+		}
+	}
+
+	return false
+}

vendor/github.com/denverdino/aliyungo/cdn/auth/sign_url.go

@@ -0,0 +1,80 @@
+package auth
+
+import (
+	"crypto/md5"
+	"fmt"
+	"net/url"
+	"time"
+)
+
+// An URLSigner provides URL signing utilities to sign URLs for Aliyun CDN
+// resources.
+// authentication document: https://help.aliyun.com/document_detail/85117.html
+type URLSigner struct {
+	authType string
+	privKey  string
+}
+
+// NewURLSigner returns a new signer object.
+func NewURLSigner(authType string, privKey string) *URLSigner {
+	return &URLSigner{
+		authType: authType,
+		privKey:  privKey,
+	}
+}
+
+// Sign returns a signed aliyuncdn url based on authentication type
+func (s URLSigner) Sign(uri string, expires time.Time) (string, error) {
+	r, err := url.Parse(uri)
+	if err != nil {
+		return "", fmt.Errorf("unable to parse url: %s", uri)
+	}
+
+	switch s.authType {
+	case "a":
+		return aTypeSign(r, s.privKey, expires), nil
+	case "b":
+		return bTypeSign(r, s.privKey, expires), nil
+	case "c":
+		return cTypeSign(r, s.privKey, expires), nil
+	default:
+		return "", fmt.Errorf("invalid authentication type")
+	}
+}
+
+// sign by A type authentication method.
+// authentication document: https://help.aliyun.com/document_detail/85113.html
+func aTypeSign(r *url.URL, privateKey string, expires time.Time) string {
+	//rand is a random uuid without "-"
+	rand := GenerateUUID().String()
+	// not use, "0" by default
+	uid := "0"
+	secret := fmt.Sprintf("%s-%d-%s-%s-%s", r.Path, expires.Unix(), rand, uid, privateKey)
+	hashValue := md5.Sum([]byte(secret))
+	authKey := fmt.Sprintf("%d-%s-%s-%x", expires.Unix(), rand, uid, hashValue)
+	if r.RawQuery == "" {
+		return fmt.Sprintf("%s?auth_key=%s", r.String(), authKey)
+	}
+	return fmt.Sprintf("%s&auth_key=%s", r.String(), authKey)
+
+}
+
+// sign by B type authentication method.
+// authentication document: https://help.aliyun.com/document_detail/85114.html
+func bTypeSign(r *url.URL, privateKey string, expires time.Time) string {
+	formatExp := expires.Format("200601021504")
+	secret := privateKey + formatExp + r.Path
+	hashValue := md5.Sum([]byte(secret))
+	signURL := fmt.Sprintf("%s://%s/%s/%x%s?%s", r.Scheme, r.Host, formatExp, hashValue, r.Path, r.RawQuery)
+	return signURL
+}
+
+// sign by C type authentication method.
+// authentication document: https://help.aliyun.com/document_detail/85115.html
+func cTypeSign(r *url.URL, privateKey string, expires time.Time) string {
+	hexExp := fmt.Sprintf("%x", expires.Unix())
+	secret := privateKey + r.Path + hexExp
+	hashValue := md5.Sum([]byte(secret))
+	signURL := fmt.Sprintf("%s://%s/%x/%s%s?%s", r.Scheme, r.Host, hashValue, hexExp, r.Path, r.RawQuery)
+	return signURL
+}