- Avoids code duplication across the other targets. By having a centralized function call. - Reduce the room for race.
152 lines
3.2 KiB
Go
152 lines
3.2 KiB
Go
/*
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* MinIO Cloud Storage, (C) 2018 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 event
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import (
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"fmt"
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"sync"
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)
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// Target - event target interface
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type Target interface {
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ID() TargetID
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Save(Event) error
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Send(string) error
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Close() error
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}
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// TargetList - holds list of targets indexed by target ID.
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type TargetList struct {
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sync.RWMutex
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targets map[TargetID]Target
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}
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// Add - adds unique target to target list.
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func (list *TargetList) Add(target Target) error {
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list.Lock()
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defer list.Unlock()
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if _, ok := list.targets[target.ID()]; ok {
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return fmt.Errorf("target %v already exists", target.ID())
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}
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list.targets[target.ID()] = target
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return nil
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}
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// Exists - checks whether target by target ID exists or not.
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func (list *TargetList) Exists(id TargetID) bool {
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list.RLock()
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defer list.RUnlock()
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_, found := list.targets[id]
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return found
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}
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// TargetIDErr returns error associated for a targetID
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type TargetIDErr struct {
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// ID where the remove or send were initiated.
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ID TargetID
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// Stores any error while removing a target or while sending an event.
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Err error
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}
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// Remove - closes and removes targets by given target IDs.
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func (list *TargetList) Remove(targetids ...TargetID) <-chan TargetIDErr {
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errCh := make(chan TargetIDErr)
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go func() {
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defer close(errCh)
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var wg sync.WaitGroup
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for _, id := range targetids {
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list.RLock()
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target, ok := list.targets[id]
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list.RUnlock()
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if ok {
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wg.Add(1)
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go func(id TargetID, target Target) {
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defer wg.Done()
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if err := target.Close(); err != nil {
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errCh <- TargetIDErr{
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ID: id,
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Err: err,
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}
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}
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}(id, target)
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}
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}
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wg.Wait()
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list.Lock()
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for _, id := range targetids {
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delete(list.targets, id)
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}
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list.Unlock()
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}()
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return errCh
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}
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// List - returns available target IDs.
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func (list *TargetList) List() []TargetID {
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list.RLock()
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defer list.RUnlock()
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keys := []TargetID{}
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for k := range list.targets {
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keys = append(keys, k)
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}
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return keys
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}
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// Send - sends events to targets identified by target IDs.
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func (list *TargetList) Send(event Event, targetIDs ...TargetID) <-chan TargetIDErr {
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errCh := make(chan TargetIDErr)
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go func() {
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defer close(errCh)
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var wg sync.WaitGroup
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for _, id := range targetIDs {
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list.RLock()
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target, ok := list.targets[id]
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list.RUnlock()
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if ok {
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wg.Add(1)
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go func(id TargetID, target Target) {
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defer wg.Done()
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if err := target.Save(event); err != nil {
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errCh <- TargetIDErr{
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ID: id,
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Err: err,
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}
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}
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}(id, target)
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}
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}
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wg.Wait()
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}()
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return errCh
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}
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// NewTargetList - creates TargetList.
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func NewTargetList() *TargetList {
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return &TargetList{targets: make(map[TargetID]Target)}
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}
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