75bd409ba0
Backend support for subscribing/unsubscribing to blocks, typically cards and boards. Notifies subscribers when changes are made to cards they are subscribed to.
132 lines
3.4 KiB
Go
132 lines
3.4 KiB
Go
// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
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// See LICENSE.txt for license information.
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package notify
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import (
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"sync"
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"github.com/mattermost/focalboard/server/model"
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"github.com/wiggin77/merror"
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"github.com/mattermost/mattermost-server/v6/shared/mlog"
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)
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type Action string
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const (
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Add Action = "add"
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Update Action = "update"
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Delete Action = "delete"
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)
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type BlockChangeEvent struct {
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Action Action
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Workspace string
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Board *model.Block
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Card *model.Block
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BlockChanged *model.Block
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BlockOld *model.Block
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ModifiedByID string
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}
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type SubscriptionChangeNotifier interface {
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BroadcastSubscriptionChange(workspaceID string, subscription *model.Subscription)
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}
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// Backend provides an interface for sending notifications.
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type Backend interface {
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Start() error
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ShutDown() error
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BlockChanged(evt BlockChangeEvent) error
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Name() string
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}
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// Service is a service that sends notifications based on block activity using one or more backends.
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type Service struct {
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mux sync.RWMutex
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backends []Backend
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logger *mlog.Logger
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}
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// New creates a notification service with one or more Backends capable of sending notifications.
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func New(logger *mlog.Logger, backends ...Backend) (*Service, error) {
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notify := &Service{
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backends: make([]Backend, 0, len(backends)),
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logger: logger,
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}
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merr := merror.New()
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for _, backend := range backends {
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if err := notify.AddBackend(backend); err != nil {
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merr.Append(err)
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} else {
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logger.Info("Initialized notification backend", mlog.String("name", backend.Name()))
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}
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}
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return notify, merr.ErrorOrNil()
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}
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// AddBackend adds a backend to the list that will be informed of any block changes.
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func (s *Service) AddBackend(backend Backend) error {
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if err := backend.Start(); err != nil {
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return err
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}
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s.mux.Lock()
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defer s.mux.Unlock()
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s.backends = append(s.backends, backend)
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return nil
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}
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// Shutdown calls shutdown for all backends.
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func (s *Service) Shutdown() error {
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s.mux.Lock()
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defer s.mux.Unlock()
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merr := merror.New()
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for _, backend := range s.backends {
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if err := backend.ShutDown(); err != nil {
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merr.Append(err)
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}
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}
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s.backends = nil
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return merr.ErrorOrNil()
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}
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// BlockChanged should be called whenever a block is added/updated/deleted.
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// All backends are informed of the event.
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func (s *Service) BlockChanged(evt BlockChangeEvent) {
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s.mux.RLock()
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defer s.mux.RUnlock()
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for _, backend := range s.backends {
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if err := backend.BlockChanged(evt); err != nil {
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s.logger.Error("Error delivering notification",
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mlog.String("backend", backend.Name()),
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mlog.String("action", string(evt.Action)),
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mlog.String("block_id", evt.BlockChanged.ID),
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mlog.Err(err),
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)
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}
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}
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}
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// BroadcastSubscriptionChange sends a websocket message with details of the changed subscription to all
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// connected users in the workspace.
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func (s *Service) BroadcastSubscriptionChange(workspaceID string, subscription *model.Subscription) {
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s.mux.RLock()
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backends := make([]Backend, len(s.backends))
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copy(backends, s.backends)
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s.mux.RUnlock()
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for _, backend := range backends {
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if scn, ok := backend.(SubscriptionChangeNotifier); ok {
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s.logger.Debug("Delivering subscription change notification",
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mlog.String("workspace_id", workspaceID),
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mlog.String("block_id", subscription.BlockID),
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mlog.String("subscriber_id", subscription.SubscriberID),
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)
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scn.BroadcastSubscriptionChange(workspaceID, subscription)
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}
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}
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}
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