feat: add backend

src/notification/BackendTransport.ts

@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2019 StApps
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+import {SMTP} from '@openstapps/logger/lib/SMTP';
+import {Transport, TransportWithVerification} from '@openstapps/logger/lib/Transport';
+
+export function isTransportWithVerification(instance: Transport): instance is TransportWithVerification {
+  return typeof (instance as TransportWithVerification).verify === 'function';
+}
+
+/**
+ * Singleton for getting only one transport service
+ *
+ * In the future this may support more than loading SMTP as a transport.
+ */
+export class BackendTransport {
+
+  private static _instance: BackendTransport;
+  private waitingForVerification: boolean;
+  protected transport: SMTP | undefined;
+
+  public static getTransportInstance(): SMTP | undefined {
+    if (this._instance) {
+      return this._instance.transport;
+    }
+
+    this._instance = new this();
+    return this._instance.transport;
+  }
+
+  private constructor() {
+    // get SMTP instance for the time
+    // in the future we may implement some other transport services which can be selected
+    // via the configuration files
+    try {
+      this.transport = SMTP.getInstance();
+    } catch (error) {
+      if (process.env.ALLOW_NO_TRANSPORT === 'true') {
+        /* tslint:disable-next-line:no-console */
+        console.warn('SMTP error was ignored.');
+      } else {
+        throw error;
+      }
+    }
+
+    if (typeof this.transport !== 'undefined' && isTransportWithVerification(this.transport)) {
+      this.waitingForVerification = true;
+
+      this.transport.verify().then((message) => {
+        if (typeof message === 'string') {
+          // tslint:disable-next-line:no-console
+          console.log(message);
+        }
+      }).catch((err) => {
+        throw err;
+      });
+    } else {
+      this.waitingForVerification = false;
+    }
+  }
+
+  public isWaitingForVerification(): boolean {
+    return this.waitingForVerification;
+  }
+}

src/notification/MailQueue.ts

@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2019 StApps
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.nse along with
+ * this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+import { SMTP } from '@openstapps/logger/lib/SMTP';
+import { MailOptions } from 'nodemailer/lib/sendmail-transport';
+import * as Queue from 'promise-queue';
+import { logger } from '../common';
+/**
+ * A queue that can send mails in serial
+ */
+export class MailQueue {
+
+  /**
+   * A queue that saves mails, before the transport is ready. When
+   * the transport gets ready this mails are getting pushed in to
+   * the normal queue.
+   */
+  dryQueue: MailOptions[];
+
+  /**
+   * A queue that saves mails, that are being sent in series
+   */
+  queue: Queue;
+
+  /**
+   * A counter for the number of verifications that failed
+   */
+  verificationCounter: number;
+
+  /**
+   * Creates a mail queue
+   * @param transport
+   */
+  constructor(private transport: SMTP) {
+
+    this.queue = new Queue(1);
+
+    // this queue saves all request when the transport is not ready yet
+    this.dryQueue = [];
+
+    this.verificationCounter = 0;
+
+    // if the transport can be verified it should check if it was done...
+    this.checkForVerification();
+  }
+
+  /**
+   * Verify the given transport
+   */
+  private checkForVerification() {
+
+    if (this.verificationCounter > 5) {
+      throw new Error('Failed to initialize the SMTP transport for the mail queue');
+    }
+
+    if (!this.transport.isVerified()) {
+      this.verificationCounter++;
+      setTimeout(() => {
+        logger.warn('Transport not verified yet. Trying to send mails here...');
+        this.checkForVerification();
+      }, 5000);
+    } else {
+      logger.ok('Transport for mail queue was verified. We can send mails now');
+      // if the transport finally was verified send all our mails from the dry queue
+      this.dryQueue.forEach((mail) => {
+        this.queue.add<string>(() => (this.transport as SMTP).sendMail(mail));
+      });
+    }
+  }
+
+  /**
+   * Push a mail into the queue so it gets send when the queue is ready
+   * @param mail
+   */
+  public push(mail: MailOptions) {
+    if (!this.transport.isVerified()) { // the transport has verification, but is not verified yet
+      // push to a dry queue which gets pushed to the real queue when the transport is verified
+      this.dryQueue.push(mail);
+    } else {
+      this.queue.add<string>(() => (this.transport as SMTP).sendMail(mail));
+    }
+  }
+}