package manager import ( "bytes" "errors" "fmt" "html/template" "log" "net/textproto" "strings" "sync" "time" "github.com/knadh/listmonk/internal/messenger" "github.com/knadh/listmonk/models" ) const ( // BaseTPL is the name of the base template. BaseTPL = "base" // ContentTpl is the name of the compiled message. ContentTpl = "content" ) // DataSource represents a data backend, such as a database, // that provides subscriber and campaign records. type DataSource interface { NextCampaigns(excludeIDs []int64) ([]*models.Campaign, error) NextSubscribers(campID, limit int) ([]models.Subscriber, error) GetCampaign(campID int) (*models.Campaign, error) UpdateCampaignStatus(campID int, status string) error CreateLink(url string) (string, error) } // Manager handles the scheduling, processing, and queuing of campaigns // and message pushes. type Manager struct { cfg Config src DataSource messengers map[string]messenger.Messenger notifCB models.AdminNotifCallback logger *log.Logger // Campaigns that are currently running. camps map[int]*models.Campaign campsMutex sync.RWMutex // Links generated using Track() are cached here so as to not query // the database for the link UUID for every message sent. This has to // be locked as it may be used externally when previewing campaigns. links map[string]string linksMutex sync.RWMutex subFetchQueue chan *models.Campaign campMsgQueue chan CampaignMessage campMsgErrorQueue chan msgError campMsgErrorCounts map[int]int msgQueue chan Message } // CampaignMessage represents an instance of campaign message to be pushed out, // specific to a subscriber, via the campaign's messenger. type CampaignMessage struct { Campaign *models.Campaign Subscriber models.Subscriber from string to string subject string body []byte unsubURL string } // Message represents a generic message to be pushed to a messenger. type Message struct { messenger.Message Subscriber models.Subscriber // Messenger is the messenger backend to use: email|postback. Messenger string } // Config has parameters for configuring the manager. type Config struct { // Number of subscribers to pull from the DB in a single iteration. BatchSize int Concurrency int MessageRate int MaxSendErrors int RequeueOnError bool FromEmail string LinkTrackURL string UnsubURL string OptinURL string MessageURL string ViewTrackURL string UnsubHeader bool } type msgError struct { camp *models.Campaign err error } // New returns a new instance of Mailer. func New(cfg Config, src DataSource, notifCB models.AdminNotifCallback, l *log.Logger) *Manager { if cfg.BatchSize < 1 { cfg.BatchSize = 1000 } if cfg.Concurrency < 1 { cfg.Concurrency = 1 } if cfg.MessageRate < 1 { cfg.MessageRate = 1 } return &Manager{ cfg: cfg, src: src, notifCB: notifCB, logger: l, messengers: make(map[string]messenger.Messenger), camps: make(map[int]*models.Campaign), links: make(map[string]string), subFetchQueue: make(chan *models.Campaign, cfg.Concurrency), campMsgQueue: make(chan CampaignMessage, cfg.Concurrency*2), msgQueue: make(chan Message, cfg.Concurrency), campMsgErrorQueue: make(chan msgError, cfg.MaxSendErrors), campMsgErrorCounts: make(map[int]int), } } // NewCampaignMessage creates and returns a CampaignMessage that is made available // to message templates while they're compiled. It represents a message from // a campaign that's bound to a single Subscriber. func (m *Manager) NewCampaignMessage(c *models.Campaign, s models.Subscriber) CampaignMessage { return CampaignMessage{ Campaign: c, Subscriber: s, subject: c.Subject, from: c.FromEmail, to: s.Email, unsubURL: fmt.Sprintf(m.cfg.UnsubURL, c.UUID, s.UUID), } } // AddMessenger adds a Messenger messaging backend to the manager. func (m *Manager) AddMessenger(msg messenger.Messenger) error { id := msg.Name() if _, ok := m.messengers[id]; ok { return fmt.Errorf("messenger '%s' is already loaded", id) } m.messengers[id] = msg return nil } // PushMessage pushes a Message to be sent out by the workers. func (m *Manager) PushMessage(msg Message) error { t := time.NewTicker(time.Second * 3) defer t.Stop() select { case m.msgQueue <- msg: case <-t.C: m.logger.Println("message push timed out: %'s'", msg.Subject) return errors.New("message push timed out") } return nil } // HasMessenger checks if a given messenger is registered. func (m *Manager) HasMessenger(id string) bool { _, ok := m.messengers[id] return ok } // HasRunningCampaigns checks if there are any active campaigns. func (m *Manager) HasRunningCampaigns() bool { m.campsMutex.Lock() defer m.campsMutex.Unlock() return len(m.camps) > 0 } // Run is a blocking function (that should be invoked as a goroutine) // that scans the data source at regular intervals for pending campaigns, // and queues them for processing. The process queue fetches batches of // subscribers and pushes messages to them for each queued campaign // until all subscribers are exhausted, at which point, a campaign is marked // as "finished". func (m *Manager) Run(tick time.Duration) { go m.scanCampaigns(tick) // Spawn N message workers. for i := 0; i < m.cfg.Concurrency; i++ { go m.messageWorker() } // Fetch the next set of subscribers for a campaign and process them. for c := range m.subFetchQueue { has, err := m.nextSubscribers(c, m.cfg.BatchSize) if err != nil { m.logger.Printf("error processing campaign batch (%s): %v", c.Name, err) continue } if has { // There are more subscribers to fetch. m.subFetchQueue <- c } else if m.isCampaignProcessing(c.ID) { // There are no more subscribers. Either the campaign status // has changed or all subscribers have been processed. newC, err := m.exhaustCampaign(c, "") if err != nil { m.logger.Printf("error exhausting campaign (%s): %v", c.Name, err) continue } m.sendNotif(newC, newC.Status, "") } } } // messageWorker is a blocking function that listens to the message queue // and pushes out incoming messages on it to the messenger. func (m *Manager) messageWorker() { // Counter to keep track of the message / sec rate limit. numMsg := 0 for { select { // Campaign message. case msg, ok := <-m.campMsgQueue: if !ok { return } // Pause on hitting the message rate. if numMsg >= m.cfg.MessageRate { time.Sleep(time.Second) numMsg = 0 } numMsg++ // Outgoing message. out := messenger.Message{ From: msg.from, To: []string{msg.to}, Subject: msg.subject, ContentType: msg.Campaign.ContentType, Body: msg.body, Subscriber: msg.Subscriber, Campaign: msg.Campaign, } // Attach List-Unsubscribe headers? if m.cfg.UnsubHeader { h := textproto.MIMEHeader{} h.Set("List-Unsubscribe-Post", "List-Unsubscribe=One-Click") h.Set("List-Unsubscribe", `<`+msg.unsubURL+`>`) out.Headers = h } if err := m.messengers[msg.Campaign.Messenger].Push(out); err != nil { m.logger.Printf("error sending message in campaign %s: %v", msg.Campaign.Name, err) select { case m.campMsgErrorQueue <- msgError{camp: msg.Campaign, err: err}: default: } } // Arbitrary message. case msg, ok := <-m.msgQueue: if !ok { return } err := m.messengers[msg.Messenger].Push(messenger.Message{ From: msg.From, To: msg.To, Subject: msg.Subject, ContentType: msg.ContentType, Body: msg.Body, Subscriber: msg.Subscriber, Campaign: msg.Campaign, }) if err != nil { m.logger.Printf("error sending message '%s': %v", msg.Subject, err) } } } } // TemplateFuncs returns the template functions to be applied into // compiled campaign templates. func (m *Manager) TemplateFuncs(c *models.Campaign) template.FuncMap { return template.FuncMap{ "TrackLink": func(url string, msg *CampaignMessage) string { return m.trackLink(url, msg.Campaign.UUID, msg.Subscriber.UUID) }, "TrackView": func(msg *CampaignMessage) template.HTML { return template.HTML(fmt.Sprintf(``, fmt.Sprintf(m.cfg.ViewTrackURL, msg.Campaign.UUID, msg.Subscriber.UUID))) }, "UnsubscribeURL": func(msg *CampaignMessage) string { return msg.unsubURL }, "OptinURL": func(msg *CampaignMessage) string { // Add list IDs. // TODO: Show private lists list on optin e-mail return fmt.Sprintf(m.cfg.OptinURL, msg.Subscriber.UUID, "") }, "MessageURL": func(msg *CampaignMessage) string { return fmt.Sprintf(m.cfg.MessageURL, c.UUID, msg.Subscriber.UUID) }, "Date": func(layout string) string { if layout == "" { layout = time.ANSIC } return time.Now().Format(layout) }, } } // Close closes and exits the campaign manager. func (m *Manager) Close() { close(m.subFetchQueue) close(m.campMsgErrorQueue) close(m.msgQueue) } // scanCampaigns is a blocking function that periodically scans the data source // for campaigns to process and dispatches them to the manager. func (m *Manager) scanCampaigns(tick time.Duration) { t := time.NewTicker(tick) for { select { // Periodically scan the data source for campaigns to process. case <-t.C: campaigns, err := m.src.NextCampaigns(m.getPendingCampaignIDs()) if err != nil { m.logger.Printf("error fetching campaigns: %v", err) continue } for _, c := range campaigns { if err := m.addCampaign(c); err != nil { m.logger.Printf("error processing campaign (%s): %v", c.Name, err) continue } m.logger.Printf("start processing campaign (%s)", c.Name) // If subscriber processing is busy, move on. Blocking and waiting // can end up in a race condition where the waiting campaign's // state in the data source has changed. select { case m.subFetchQueue <- c: default: } } // Aggregate errors from sending messages to check against the error threshold // after which a campaign is paused. case e, ok := <-m.campMsgErrorQueue: if !ok { return } if m.cfg.MaxSendErrors < 1 { continue } // If the error threshold is met, pause the campaign. m.campMsgErrorCounts[e.camp.ID]++ if m.campMsgErrorCounts[e.camp.ID] >= m.cfg.MaxSendErrors { m.logger.Printf("error counted exceeded %d. pausing campaign %s", m.cfg.MaxSendErrors, e.camp.Name) if m.isCampaignProcessing(e.camp.ID) { m.exhaustCampaign(e.camp, models.CampaignStatusPaused) } delete(m.campMsgErrorCounts, e.camp.ID) // Notify admins. m.sendNotif(e.camp, models.CampaignStatusPaused, "Too many errors") } } } } // addCampaign adds a campaign to the process queue. func (m *Manager) addCampaign(c *models.Campaign) error { // Validate messenger. if _, ok := m.messengers[c.Messenger]; !ok { m.src.UpdateCampaignStatus(c.ID, models.CampaignStatusCancelled) return fmt.Errorf("unknown messenger %s on campaign %s", c.Messenger, c.Name) } // Load the template. if err := c.CompileTemplate(m.TemplateFuncs(c)); err != nil { return err } // Add the campaign to the active map. m.campsMutex.Lock() m.camps[c.ID] = c m.campsMutex.Unlock() return nil } // getPendingCampaignIDs returns the IDs of campaigns currently being processed. func (m *Manager) getPendingCampaignIDs() []int64 { // Needs to return an empty slice in case there are no campaigns. m.campsMutex.RLock() ids := make([]int64, 0, len(m.camps)) for _, c := range m.camps { ids = append(ids, int64(c.ID)) } m.campsMutex.RUnlock() return ids } // nextSubscribers processes the next batch of subscribers in a given campaign. // If returns a bool indicating whether there any subscribers were processed // in the current batch or not. This can happen when all the subscribers // have been processed, or if a campaign has been paused or cancelled abruptly. func (m *Manager) nextSubscribers(c *models.Campaign, batchSize int) (bool, error) { // Fetch a batch of subscribers. subs, err := m.src.NextSubscribers(c.ID, batchSize) if err != nil { return false, fmt.Errorf("error fetching campaign subscribers (%s): %v", c.Name, err) } // There are no subscribers. if len(subs) == 0 { return false, nil } // Push messages. for _, s := range subs { msg := m.NewCampaignMessage(c, s) if err := msg.Render(); err != nil { m.logger.Printf("error rendering message (%s) (%s): %v", c.Name, s.Email, err) continue } // Push the message to the queue while blocking and waiting until // the queue is drained. m.campMsgQueue <- msg } return true, nil } // isCampaignProcessing checks if the campaign is bing processed. func (m *Manager) isCampaignProcessing(id int) bool { m.campsMutex.RLock() _, ok := m.camps[id] m.campsMutex.RUnlock() return ok } func (m *Manager) exhaustCampaign(c *models.Campaign, status string) (*models.Campaign, error) { m.campsMutex.Lock() delete(m.camps, c.ID) m.campsMutex.Unlock() // A status has been passed. Change the campaign's status // without further checks. if status != "" { if err := m.src.UpdateCampaignStatus(c.ID, status); err != nil { m.logger.Printf("error updating campaign (%s) status to %s: %v", c.Name, status, err) } else { m.logger.Printf("set campaign (%s) to %s", c.Name, status) } return c, nil } // Fetch the up-to-date campaign status from the source. cm, err := m.src.GetCampaign(c.ID) if err != nil { return nil, err } // If a running campaign has exhausted subscribers, it's finished. if cm.Status == models.CampaignStatusRunning { cm.Status = models.CampaignStatusFinished if err := m.src.UpdateCampaignStatus(c.ID, models.CampaignStatusFinished); err != nil { m.logger.Printf("error finishing campaign (%s): %v", c.Name, err) } else { m.logger.Printf("campaign (%s) finished", c.Name) } } else { m.logger.Printf("stop processing campaign (%s)", c.Name) } return cm, nil } // trackLink register a URL and return its UUID to be used in message templates // for tracking links. func (m *Manager) trackLink(url, campUUID, subUUID string) string { m.linksMutex.RLock() if uu, ok := m.links[url]; ok { m.linksMutex.RUnlock() return fmt.Sprintf(m.cfg.LinkTrackURL, uu, campUUID, subUUID) } m.linksMutex.RUnlock() // Register link. uu, err := m.src.CreateLink(url) if err != nil { m.logger.Printf("error registering tracking for link '%s': %v", url, err) // If the registration fails, fail over to the original URL. return url } m.linksMutex.Lock() m.links[url] = uu m.linksMutex.Unlock() return fmt.Sprintf(m.cfg.LinkTrackURL, uu, campUUID, subUUID) } // sendNotif sends a notification to registered admin e-mails. func (m *Manager) sendNotif(c *models.Campaign, status, reason string) error { var ( subject = fmt.Sprintf("%s: %s", strings.Title(status), c.Name) data = map[string]interface{}{ "ID": c.ID, "Name": c.Name, "Status": status, "Sent": c.Sent, "ToSend": c.ToSend, "Reason": reason, } ) return m.notifCB(subject, data) } // Render takes a Message, executes its pre-compiled Campaign.Tpl // and applies the resultant bytes to Message.body to be used in messages. func (m *CampaignMessage) Render() error { out := bytes.Buffer{} // Render the subject if it's a template. if m.Campaign.SubjectTpl != nil { if err := m.Campaign.SubjectTpl.ExecuteTemplate(&out, models.ContentTpl, m); err != nil { return err } m.subject = out.String() out.Reset() } if err := m.Campaign.Tpl.ExecuteTemplate(&out, models.BaseTpl, m); err != nil { return err } m.body = out.Bytes() return nil } // Subject returns a copy of the message subject func (m *CampaignMessage) Subject() string { return m.subject } // Body returns a copy of the message body. func (m *CampaignMessage) Body() []byte { out := make([]byte, len(m.body)) copy(out, m.body) return out }