[FIX] Email inbox memory leak on connection failure (#26850)

Co-authored-by: Kevin Aleman <11577696+KevLehman@users.noreply.github.com>

apps/meteor/app/models/server/models/LivechatRooms.js

@@ -209,7 +209,10 @@ export class LivechatRooms extends Base {
 		const query = {
 			't': 'l',
 			'v.token': visitorToken,
-			'$or': [{ 'email.thread': { $elemMatch: { $in: emailThread } } }, { 'email.thread': new RegExp(emailThread.join('|')) }],
+			'$or': [
+				{ 'email.thread': { $elemMatch: { $in: emailThread } } },
+				{ 'email.thread': new RegExp(emailThread.map((t) => `"${t}"`).join('|')) },
+			],
 			...(departmentId && { departmentId }),
 		};
 

apps/meteor/server/email/IMAPInterceptor.ts

@@ -1,9 +1,10 @@
 import { EventEmitter } from 'events';
 
+import type { ImapMessage, ImapMessageBodyInfo } from 'imap';
 import IMAP from 'imap';
-import type Connection from 'imap';
 import type { ParsedMail } from 'mailparser';
 import { simpleParser } from 'mailparser';
+import { EmailInbox } from '@rocket.chat/models';
 
 import { logger } from '../features/EmailInbox/logger';
 
@@ -24,12 +25,14 @@ export class IMAPInterceptor extends EventEmitter {
 
 	private config: IMAP.Config;
 
-	private initialBackoffDurationMS = 30000;
+	private backoffDurationMS = 3000;
 
 	private backoff: NodeJS.Timeout;
 
 	private retries = 0;
 
+	private inboxId: string;
+
 	constructor(
 		imapConfig: IMAP.Config,
 		private options: IMAPOptions = {
@@ -38,6 +41,7 @@ export class IMAPInterceptor extends EventEmitter {
 			markSeen: true,
 			maxRetries: 10,
 		},
+		id: string,
 	) {
 		super();
 
@@ -49,132 +53,178 @@ export class IMAPInterceptor extends EventEmitter {
 			...(imapConfig.tls && { tlsOptions: { servername: imapConfig.host } }),
 			...imapConfig,
 		});
+		this.retries = 0;
+		this.inboxId = id;
+		this.start();
+	}
+
+	openInbox(): Promise<IMAP.Box> {
+		return new Promise((resolve, reject) => {
+			const cb = (err: Error, mailbox: IMAP.Box) => {
+				if (err) {
+					reject(err);
+				} else {
+					resolve(mailbox);
+				}
+			};
+			this.imap.openBox('INBOX', false, cb);
+		});
+	}
 
+	async start(): Promise<void> {
 		// On successfully connected.
-		this.imap.on('ready', () => {
-			if (this.imap.state !== 'disconnected') {
+		this.imap.on('ready', async () => {
+			if (this.isActive()) {
+				logger.info(`IMAP connected to ${this.config.user}`);
 				clearTimeout(this.backoff);
 				this.retries = 0;
-				this.openInbox((err) => {
-					if (err) {
-						logger.error(`Error occurred during imap on inbox ${this.config.user}: `, err);
-						throw err;
-					}
-					// fetch new emails & wait [IDLE]
-					this.getEmails();
-
-					// If new message arrived, fetch them
-					this.imap.on('mail', () => {
-						this.getEmails();
-					});
-				});
+				this.backoffDurationMS = 3000;
+				await this.openInbox();
+				this.imap.on('mail', () => this.getEmails().catch((err: Error) => logger.debug('Error on getEmails: ', err.message)));
 			} else {
-				logger.error(`IMAP did not connect on inbox ${this.config.user}`);
-				this.imap.end();
-				this.reconnect();
+				logger.error("Can't connect to IMAP server");
 			}
 		});
 
-		this.imap.on('error', (err: Error) => {
-			logger.error(`Error occurred on inbox ${this.config.user}: `, err);
-			this.stop(() => this.reconnect());
+		this.imap.on('error', async (err: Error) => {
+			logger.error({ err });
+			logger.error(`IMAP error: ${err.message}`);
+			this.retries++;
+			await this.reconnect();
 		});
 
-		this.imap.on('close', () => {
-			this.reconnect();
+		this.imap.on('close', async () => {
+			await this.reconnect();
 		});
-	}
-
-	openInbox(cb: (error: Error, mailbox: Connection.Box) => void): void {
-		this.imap.openBox('INBOX', false, cb);
-	}
-
-	start(): void {
-		this.imap.connect();
+		this.retries += 1;
+		return this.imap.connect();
 	}
 
 	isActive(): boolean {
-		if (this.imap?.state && this.imap.state === 'disconnected') {
-			return false;
-		}
-
-		return true;
+		return !!(this.imap?.state && this.imap.state !== 'disconnected');
 	}
 
 	stop(callback = new Function()): void {
-		logger.info('IMAP stop called');
-		this.imap.end();
+		logger.debug('IMAP stop called');
+		this.imap.removeAllListeners();
 		this.imap.once('end', () => {
-			logger.info('IMAP stopped');
+			logger.debug('IMAP stopped');
 			callback?.();
 		});
+		this.imap.end();
 	}
 
-	reconnect(): void {
+	async reconnect(): Promise<void> {
+		if (!this.isActive() && !this.canRetry()) {
+			logger.info(`Max retries reached for ${this.config.user}`);
+			this.stop();
+			return this.selfDisable();
+		}
+		if (this.backoff) {
+			clearTimeout(this.backoff);
+			this.backoffDurationMS = 3000;
+		}
 		const loop = (): void => {
-			this.start();
-			if (this.retries < this.options.maxRetries) {
-				this.retries += 1;
-				this.initialBackoffDurationMS *= 2;
-				this.backoff = setTimeout(loop, this.initialBackoffDurationMS);
+			logger.debug(`Reconnecting to ${this.config.user}: ${this.retries}`);
+			if (this.canRetry()) {
+				this.backoffDurationMS *= 2;
+				this.backoff = setTimeout(loop, this.backoffDurationMS);
 			} else {
-				logger.error(`IMAP reconnection failed on inbox ${this.config.user}`);
+				logger.info(`IMAP reconnection failed on inbox ${this.config.user}`);
 				clearTimeout(this.backoff);
+				this.stop();
+				this.selfDisable();
+				return;
 			}
+			this.stop();
+			this.start();
 		};
-		this.backoff = setTimeout(loop, this.initialBackoffDurationMS);
+		this.backoff = setTimeout(loop, this.backoffDurationMS);
 	}
 
-	// Fetch all UNSEEN messages and pass them for further processing
-	getEmails(): void {
-		this.imap.search(this.options.filter, (err, newEmails) => {
-			logger.debug(`IMAP search on inbox ${this.config.user} returned ${newEmails.length} new emails: `, newEmails);
-			if (err) {
-				logger.error(err);
-				throw err;
-			}
-			// newEmails => array containing serials of unseen messages
-			if (newEmails.length > 0) {
-				const fetch = this.imap.fetch(newEmails, {
-					bodies: ['HEADER', 'TEXT', ''],
-					struct: true,
-					markSeen: this.options.markSeen,
-				});
-
-				fetch.on('message', (msg, seqno) => {
-					logger.debug('E-mail received', seqno, msg);
-
-					msg.on('body', (stream, type) => {
-						if (type.which !== '') {
-							return;
-						}
+	imapSearch(): Promise<number[]> {
+		return new Promise((resolve, reject) => {
+			const cb = (err: Error, results: number[]) => {
+				if (err) {
+					reject(err);
+				} else {
+					resolve(results);
+				}
+			};
+			this.imap.search(this.options.filter, cb);
+		});
+	}
 
-						simpleParser(stream, (_err, email) => {
-							if (this.options.rejectBeforeTS && email.date && email.date < this.options.rejectBeforeTS) {
-								logger.error(`Rejecting email on inbox ${this.config.user}`, email.subject);
-								return;
-							}
-							this.emit('email', email);
-						});
-					});
+	parseEmails(stream: NodeJS.ReadableStream, _info: ImapMessageBodyInfo): Promise<ParsedMail> {
+		return new Promise((resolve, reject) => {
+			const cb = (err: Error, mail: ParsedMail) => {
+				if (err) {
+					reject(err);
+				} else {
+					resolve(mail);
+				}
+			};
+			simpleParser(stream, cb);
+		});
+	}
 
-					// On fetched each message, pass it further
-					msg.once('end', () => {
-						// delete message from inbox
+	imapFetch(emailIds: number[]): Promise<number[]> {
+		return new Promise((resolve, reject) => {
+			const out: number[] = [];
+			const messagecb = (msg: ImapMessage, seqno: number) => {
+				out.push(seqno);
+				const bodycb = (stream: NodeJS.ReadableStream, _info: ImapMessageBodyInfo): void => {
+					simpleParser(stream, (_err, email) => {
+						if (this.options.rejectBeforeTS && email.date && email.date < this.options.rejectBeforeTS) {
+							logger.error(`Rejecting email on inbox ${this.config.user}`, email.subject);
+							return;
+						}
+						this.emit('email', email);
 						if (this.options.deleteAfterRead) {
-							this.imap.seq.addFlags(seqno, 'Deleted', (err) => {
+							this.imap.seq.addFlags(email, 'Deleted', (err) => {
 								if (err) {
-									logger.error(`Mark deleted error: ${err}`);
+									logger.warn(`Mark deleted error: ${err}`);
 								}
 							});
 						}
 					});
-				});
-
-				fetch.once('error', (err) => {
-					logger.error(`Fetch error: ${err}`);
-				});
-			}
+				};
+				msg.once('body', bodycb);
+			};
+			const errorcb = (err: Error): void => {
+				logger.warn(`Fetch error: ${err}`);
+				reject(err);
+			};
+			const endcb = (): void => {
+				resolve(out);
+			};
+			const fetch = this.imap.fetch(emailIds, {
+				bodies: ['HEADER', 'TEXT', ''],
+				struct: true,
+				markSeen: this.options.markSeen,
+			});
+
+			fetch.on('message', messagecb);
+			fetch.on('error', errorcb);
+			fetch.on('end', endcb);
 		});
 	}
+
+	// Fetch all UNSEEN messages and pass them for further processing
+	async getEmails(): Promise<void> {
+		const emailIds = await this.imapSearch();
+		await this.imapFetch(emailIds);
+	}
+
+	canRetry(): boolean {
+		return this.retries < this.options.maxRetries || this.options.maxRetries === -1;
+	}
+
+	async selfDisable(): Promise<void> {
+		logger.info(`Disabling inbox ${this.inboxId}`);
+		// Again, if there's 2 inboxes with the same email, this will prevent looping over the already disabled one
+		// Active filter is just in case :)
+		await EmailInbox.findOneAndUpdate({ _id: this.inboxId, active: true }, { $set: { active: false } });
+		logger.info(`IMAP inbox ${this.inboxId} automatically disabled`);
+	}
 }

apps/meteor/server/features/EmailInbox/EmailInbox.ts

@@ -49,11 +49,12 @@ export async function configureEmailInboxes(): Promise<void> {
 			},
 			{
 				deleteAfterRead: false,
-				filter: [['UNSEEN'], ['SINCE', emailInboxRecord._updatedAt]],
-				rejectBeforeTS: emailInboxRecord._updatedAt,
+				filter: [['UNSEEN'], ['SINCE', emailInboxRecord._createdAt]],
+				rejectBeforeTS: emailInboxRecord._createdAt,
 				markSeen: true,
 				maxRetries: emailInboxRecord.imap.maxRetries,
 			},
+			emailInboxRecord._id,
 		);
 
 		imap.on(

apps/meteor/server/features/EmailInbox/EmailInbox_Incoming.ts

@@ -127,7 +127,7 @@ async function uploadAttachment(attachment: Attachment, rid: string, visitorToke
 }
 
 export async function onEmailReceived(email: ParsedMail, inbox: string, department = ''): Promise<void> {
-	logger.debug(`New email conversation received on inbox ${inbox}. Will be assigned to department ${department}`, email);
+	logger.debug(`New email conversation received on inbox ${inbox}. Will be assigned to department ${department}`);
 	if (!email.from?.value?.[0]?.address) {
 		return;
 	}
@@ -161,12 +161,18 @@ export async function onEmailReceived(email: ParsedMail, inbox: string, departme
 		room = await QueueManager.unarchiveRoom(room);
 	}
 
-	let msg = email.text;
-
-	if (email.html) {
-		// Try to remove the signature and history
-		msg = stripHtml(email.html.replace(/<div name="messageSignatureSection.+/s, '')).result;
-	}
+	// TODO: html => md with turndown
+	const msg = email.html
+		? stripHtml(email.html, {
+				dumpLinkHrefsNearby: {
+					enabled: true,
+					putOnNewLine: false,
+					wrapHeads: '(',
+					wrapTails: ')',
+				},
+				skipHtmlDecoding: false,
+		  }).result
+		: email.text || '';
 
 	const rid = room?._id ?? Random.id();
 	const msgId = Random.id();