190 lines
3.8 KiB
Go
190 lines
3.8 KiB
Go
/*
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* MinIO Cloud Storage, (C) 2019 MinIO, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package target
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import (
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"encoding/json"
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"io/ioutil"
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"os"
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"path/filepath"
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"sort"
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"sync"
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"github.com/minio/minio/pkg/event"
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"github.com/minio/minio/pkg/sys"
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)
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const (
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maxLimit = 10000 // Max store limit.
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eventExt = ".event"
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)
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// QueueStore - Filestore for persisting events.
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type QueueStore struct {
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sync.RWMutex
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directory string
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eC uint64
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limit uint64
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}
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// NewQueueStore - Creates an instance for QueueStore.
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func NewQueueStore(directory string, limit uint64) *QueueStore {
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if limit == 0 {
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limit = maxLimit
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currRlimit, _, err := sys.GetMaxOpenFileLimit()
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if err == nil {
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if currRlimit > limit {
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limit = currRlimit
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}
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}
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}
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queueStore := &QueueStore{
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directory: directory,
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limit: limit,
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}
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return queueStore
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}
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// Open - Creates the directory if not present.
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func (store *QueueStore) Open() error {
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store.Lock()
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defer store.Unlock()
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if terr := os.MkdirAll(store.directory, os.FileMode(0770)); terr != nil {
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return terr
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}
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eCount := uint64(len(store.list()))
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if eCount >= store.limit {
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return errLimitExceeded
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}
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store.eC = eCount
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return nil
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}
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// write - writes event to the directory.
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func (store *QueueStore) write(directory string, key string, e event.Event) error {
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// Marshalls the event.
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eventData, err := json.Marshal(e)
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if err != nil {
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return err
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}
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path := filepath.Join(store.directory, key+eventExt)
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if err := ioutil.WriteFile(path, eventData, os.FileMode(0770)); err != nil {
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return err
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}
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// Increment the event count.
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store.eC++
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return nil
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}
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// Put - puts a event to the store.
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func (store *QueueStore) Put(e event.Event) error {
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store.Lock()
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defer store.Unlock()
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if store.eC >= store.limit {
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return errLimitExceeded
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}
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key, kErr := getNewUUID()
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if kErr != nil {
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return kErr
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}
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return store.write(store.directory, key, e)
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}
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// Get - gets a event from the store.
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func (store *QueueStore) Get(key string) (event.Event, error) {
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store.RLock()
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defer store.RUnlock()
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var event event.Event
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filepath := filepath.Join(store.directory, key+eventExt)
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eventData, rerr := ioutil.ReadFile(filepath)
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if rerr != nil {
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store.del(key)
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return event, rerr
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}
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if len(eventData) == 0 {
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store.del(key)
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}
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uerr := json.Unmarshal(eventData, &event)
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if uerr != nil {
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store.del(key)
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return event, uerr
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}
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return event, nil
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}
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// Del - Deletes an entry from the store.
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func (store *QueueStore) Del(key string) error {
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store.Lock()
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defer store.Unlock()
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return store.del(key)
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}
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// lockless call
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func (store *QueueStore) del(key string) error {
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p := filepath.Join(store.directory, key+eventExt)
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rerr := os.Remove(p)
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if rerr != nil {
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return rerr
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}
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// Decrement the event count.
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store.eC--
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return nil
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}
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// List - lists all files from the directory.
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func (store *QueueStore) List() []string {
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store.RLock()
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defer store.RUnlock()
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return store.list()
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}
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// lockless call.
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func (store *QueueStore) list() []string {
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var names []string
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storeDir, _ := os.Open(store.directory)
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files, _ := storeDir.Readdir(-1)
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// Sort the dentries.
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sort.Slice(files, func(i, j int) bool {
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return files[i].ModTime().Unix() < files[j].ModTime().Unix()
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})
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for _, file := range files {
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names = append(names, file.Name())
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}
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_ = storeDir.Close()
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return names
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}
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