minio/cmd/object-api-common.go
poornas a3e806ed61 Add disk based edge caching support. (#5182)
This PR adds disk based edge caching support for minio server.

Cache settings can be configured in config.json to take list of disk drives,
cache expiry in days and file patterns to exclude from cache or via environment
variables MINIO_CACHE_DRIVES, MINIO_CACHE_EXCLUDE and MINIO_CACHE_EXPIRY

Design assumes that Atime support is enabled and the list of cache drives is
fixed.
 - Objects are cached on both GET and PUT/POST operations.
 - Expiry is used as hint to evict older entries from cache, or if 80% of cache
   capacity is filled.
 - When object storage backend is down, GET, LIST and HEAD operations fetch
   object seamlessly from cache.

Current Limitations
 - Bucket policies are not cached, so anonymous operations are not supported in
   offline mode.
 - Objects are distributed using deterministic hashing among list of cache
   drives specified.If one or more drives go offline, or cache drive
   configuration is altered - performance could degrade to linear lookup.

Fixes #4026
2018-03-28 14:14:06 -07:00

161 lines
4.7 KiB
Go

/*
* Minio Cloud Storage, (C) 2016, 2017, 2018 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 cmd
import (
"context"
"path"
"sync"
humanize "github.com/dustin/go-humanize"
"github.com/minio/minio/pkg/errors"
)
const (
// Block size used for all internal operations version 1.
blockSizeV1 = 10 * humanize.MiByte
// Staging buffer read size for all internal operations version 1.
readSizeV1 = 1 * humanize.MiByte
// Buckets meta prefix.
bucketMetaPrefix = "buckets"
// ETag (hex encoded md5sum) of empty string.
emptyETag = "d41d8cd98f00b204e9800998ecf8427e"
)
// Global object layer mutex, used for safely updating object layer.
var globalObjLayerMutex *sync.RWMutex
// Global object layer, only accessed by newObjectLayerFn().
var globalObjectAPI ObjectLayer
//Global cacheObjects, only accessed by newCacheObjectsFn().
var globalCacheObjectAPI CacheObjectLayer
func init() {
// Initialize this once per server initialization.
globalObjLayerMutex = &sync.RWMutex{}
}
// Checks if the object is a directory, this logic uses
// if size == 0 and object ends with slashSeparator then
// returns true.
func isObjectDir(object string, size int64) bool {
return hasSuffix(object, slashSeparator) && size == 0
}
// Converts just bucket, object metadata into ObjectInfo datatype.
func dirObjectInfo(bucket, object string, size int64, metadata map[string]string) ObjectInfo {
// This is a special case with size as '0' and object ends with
// a slash separator, we treat it like a valid operation and
// return success.
etag := metadata["etag"]
delete(metadata, "etag")
if etag == "" {
etag = emptyETag
}
return ObjectInfo{
Bucket: bucket,
Name: object,
ModTime: UTCNow(),
ContentType: "application/octet-stream",
IsDir: true,
Size: size,
ETag: etag,
UserDefined: metadata,
}
}
func deleteBucketMetadata(bucket string, objAPI ObjectLayer) {
// Delete bucket access policy, if present - ignore any errors.
_ = removeBucketPolicy(bucket, objAPI)
// Delete notification config, if present - ignore any errors.
_ = removeNotificationConfig(objAPI, bucket)
// Delete listener config, if present - ignore any errors.
_ = removeListenerConfig(objAPI, bucket)
}
// Depending on the disk type network or local, initialize storage API.
func newStorageAPI(endpoint Endpoint) (storage StorageAPI, err error) {
if endpoint.IsLocal {
return newPosix(endpoint.Path)
}
return newStorageRPC(endpoint), nil
}
// Cleanup a directory recursively.
func cleanupDir(storage StorageAPI, volume, dirPath string) error {
var delFunc func(string) error
// Function to delete entries recursively.
delFunc = func(entryPath string) error {
if !hasSuffix(entryPath, slashSeparator) {
// Delete the file entry.
return errors.Trace(storage.DeleteFile(volume, entryPath))
}
// If it's a directory, list and call delFunc() for each entry.
entries, err := storage.ListDir(volume, entryPath)
// If entryPath prefix never existed, safe to ignore.
if err == errFileNotFound {
return nil
} else if err != nil { // For any other errors fail.
return errors.Trace(err)
} // else on success..
// Entry path is empty, just delete it.
if len(entries) == 0 {
return errors.Trace(storage.DeleteFile(volume, path.Clean(entryPath)))
}
// Recurse and delete all other entries.
for _, entry := range entries {
if err = delFunc(pathJoin(entryPath, entry)); err != nil {
return err
}
}
return nil
}
err := delFunc(retainSlash(pathJoin(dirPath)))
return err
}
// Removes notification.xml for a given bucket, only used during DeleteBucket.
func removeNotificationConfig(objAPI ObjectLayer, bucket string) error {
// Verify bucket is valid.
if !IsValidBucketName(bucket) {
return BucketNameInvalid{Bucket: bucket}
}
ncPath := path.Join(bucketConfigPrefix, bucket, bucketNotificationConfig)
return objAPI.DeleteObject(context.Background(), minioMetaBucket, ncPath)
}
// Remove listener configuration from storage layer. Used when a bucket is deleted.
func removeListenerConfig(objAPI ObjectLayer, bucket string) error {
// make the path
lcPath := path.Join(bucketConfigPrefix, bucket, bucketListenerConfig)
return objAPI.DeleteObject(context.Background(), minioMetaBucket, lcPath)
}