/
bucket-cache.go
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/
bucket-cache.go
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/*
* Minio Go Library for Amazon S3 Compatible Cloud Storage (C) 2015 Minio, Inc.
*
* 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 minio
import (
"encoding/hex"
"net/http"
"net/url"
"path/filepath"
"sync"
)
// bucketLocationCache - Provides simple mechansim to hold bucket
// locations in memory.
type bucketLocationCache struct {
// mutex is used for handling the concurrent
// read/write requests for cache.
sync.RWMutex
// items holds the cached bucket locations.
items map[string]string
}
// newBucketLocationCache - Provides a new bucket location cache to be
// used internally with the client object.
func newBucketLocationCache() *bucketLocationCache {
return &bucketLocationCache{
items: make(map[string]string),
}
}
// Get - Returns a value of a given key if it exists.
func (r *bucketLocationCache) Get(bucketName string) (location string, ok bool) {
r.RLock()
defer r.RUnlock()
location, ok = r.items[bucketName]
return
}
// Set - Will persist a value into cache.
func (r *bucketLocationCache) Set(bucketName string, location string) {
r.Lock()
defer r.Unlock()
r.items[bucketName] = location
}
// Delete - Deletes a bucket name from cache.
func (r *bucketLocationCache) Delete(bucketName string) {
r.Lock()
defer r.Unlock()
delete(r.items, bucketName)
}
// getBucketLocation - Get location for the bucketName from location map cache.
func (c Client) getBucketLocation(bucketName string) (string, error) {
// For anonymous requests, default to "us-east-1" and let other calls
// move forward.
if c.anonymous {
return "us-east-1", nil
}
if location, ok := c.bucketLocCache.Get(bucketName); ok {
return location, nil
}
// Initialize a new request.
req, err := c.getBucketLocationRequest(bucketName)
if err != nil {
return "", err
}
// Initiate the request.
resp, err := c.do(req)
defer closeResponse(resp)
if err != nil {
return "", err
}
if resp != nil {
if resp.StatusCode != http.StatusOK {
return "", httpRespToErrorResponse(resp, bucketName, "")
}
}
// Extract location.
var locationConstraint string
err = xmlDecoder(resp.Body, &locationConstraint)
if err != nil {
return "", err
}
location := locationConstraint
// Location is empty will be 'us-east-1'.
if location == "" {
location = "us-east-1"
}
// Location can be 'EU' convert it to meaningful 'eu-west-1'.
if location == "EU" {
location = "eu-west-1"
}
// Save the location into cache.
c.bucketLocCache.Set(bucketName, location)
// Return.
return location, nil
}
// getBucketLocationRequest - Wrapper creates a new getBucketLocation request.
func (c Client) getBucketLocationRequest(bucketName string) (*http.Request, error) {
// Set location query.
urlValues := make(url.Values)
urlValues.Set("location", "")
// Set get bucket location always as path style.
targetURL := c.endpointURL
targetURL.Path = filepath.Join(bucketName, "") + "/"
targetURL.RawQuery = urlValues.Encode()
// Get a new HTTP request for the method.
req, err := http.NewRequest("GET", targetURL.String(), nil)
if err != nil {
return nil, err
}
// Set UserAgent for the request.
c.setUserAgent(req)
// Set sha256 sum for signature calculation only with signature version '4'.
if c.signature.isV4() {
req.Header.Set("X-Amz-Content-Sha256", hex.EncodeToString(sum256([]byte{})))
}
// Sign the request.
if c.signature.isV4() {
req = signV4(*req, c.accessKeyID, c.secretAccessKey, "us-east-1")
} else if c.signature.isV2() {
req = signV2(*req, c.accessKeyID, c.secretAccessKey)
}
return req, nil
}