vendor: add packages needed for azure support

vendor/github.com/PaulARoy/azurestoragecache/azurestoragecache.go

@@ -0,0 +1,136 @@
+// Copyright 2017 Paul Roy All rights reserved.
+//
+// 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 azurestoragecache provides an implementation of httpcache.Cache that
+// stores and retrieves data using Azure Storage.
+package azurestoragecache // import "github.com/PaulARoy/azurestoragecache"
+
+import (
+	"bytes"
+	"crypto/md5"
+	"encoding/hex"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+	"strconv"
+
+	"github.com/Azure/azure-sdk-for-go/storage"
+)
+
+// Cache stores and retrieves data using Azure Storage.
+type Cache struct {
+	// The Azure Blob Storage Client
+	client storage.BlobStorageClient
+
+	// container name to use to store blobs
+	container string
+}
+
+var noLogErrors, _ = strconv.ParseBool(os.Getenv("NO_LOG_AZUREBSCACHE_ERRORS"))
+
+func keyToFilename(key string) string {
+	h := md5.New()
+	io.WriteString(h, key)
+	return hex.EncodeToString(h.Sum(nil))
+}
+
+// blob retrieves a storage.Blob reference for the specified key.
+func (c *Cache) blob(key string) *storage.Blob {
+	return c.client.GetContainerReference(c.container).GetBlobReference(key)
+}
+
+// Get the cached value with the specified key.
+func (c *Cache) Get(key string) (resp []byte, ok bool) {
+	key = keyToFilename(key)
+	rdr, err := c.blob(key).Get(nil)
+	if err != nil {
+		return []byte{}, false
+	}
+
+	resp, err = ioutil.ReadAll(rdr)
+	if err != nil {
+		if !noLogErrors {
+			log.Printf("azurestoragecache.Get failed: %s", err)
+		}
+	}
+
+	rdr.Close()
+	return resp, err == nil
+}
+
+// Set the cached value with the specified key.
+func (c *Cache) Set(key string, value []byte) {
+	key = keyToFilename(key)
+	err := c.blob(key).CreateBlockBlobFromReader(bytes.NewReader(value), nil)
+	if err != nil {
+		if !noLogErrors {
+			log.Printf("azurestoragecache.Set failed: %s", err)
+		}
+		return
+	}
+}
+
+// Delete the cached value with the specified key.
+func (c *Cache) Delete(key string) {
+	key = keyToFilename(key)
+	res, err := c.blob(key).DeleteIfExists(nil)
+	if !noLogErrors {
+		log.Printf("azurestoragecache.Delete result: %s", res)
+	}
+	if err != nil {
+		if !noLogErrors {
+			log.Printf("azurestoragecache.Delete failed: %s", err)
+		}
+	}
+}
+
+// New returns a new Cache with underlying client for Azure Storage.
+//
+// accountName and accountKey are the Azure Storage credentials.  If either are
+// empty, the contents of the environment variables AZURESTORAGE_ACCOUNT_NAME
+// and AZURESTORAGE_ACCESS_KEY will be used.
+//
+// containerName is the container name in which cached values will be stored.
+// If not specified, "cache" will be used.
+func New(accountName string, accountKey string, containerName string) (*Cache, error) {
+	if accountName == "" {
+		accountName = os.Getenv("AZURESTORAGE_ACCOUNT_NAME")
+	}
+
+	if accountKey == "" {
+		accountKey = os.Getenv("AZURESTORAGE_ACCESS_KEY")
+	}
+
+	if containerName == "" {
+		containerName = "cache"
+	}
+
+	client, err := storage.NewBasicClient(accountName, accountKey)
+	if err != nil {
+		return nil, err
+	}
+
+	cache := Cache{
+		client:    client.GetBlobService(),
+		container: containerName,
+	}
+
+	_, err = cache.client.GetContainerReference(cache.container).CreateIfNotExists(&storage.CreateContainerOptions{Access: storage.ContainerAccessTypeBlob})
+	if err != nil {
+		return nil, err
+	}
+
+	return &cache, nil
+}