(SBL-34-583) Feature: Invite email sending with a cron job

api/migrations/20211027105721_alter_invites_table_add_email_status.js

@@ -0,0 +1,9 @@
+export const up = (knex) =>
+  knex.schema.alterTable('invites', (table) => {
+    table.enum('email_status', ['error', 'pending', 'success']);
+  });
+
+export const down = (knex) =>
+  knex.schema.alterTable('invites', (table) => {
+    table.dropColumn('email_status');
+  });

api/src/config/globals.js

@@ -136,3 +136,9 @@ export const invitesStatuses = {
   PENDING: 'pending',
   SUCCESS: 'success',
 };
+
+export const emailStatuses = {
+  ERROR: 'error',
+  PENDING: 'pending',
+  SUCCESS: 'success',
+};

api/src/models/Invite.js

@@ -4,7 +4,6 @@ import {
   invitesServiceErrors,
   invitesStatuses,
   lessonServiceErrors as errors,
-  resources,
 } from '../config';
 
 class Invite extends BaseModel {
@@ -21,6 +20,7 @@ class Invite extends BaseModel {
         resourceType: { type: 'string' },
         status: { type: 'string' },
         email: { type: 'string' },
+        emailStatus: { type: 'string' },
         createdAt: { type: 'string' },
       },
     };

api/src/services/invites/controllers/createInvite.js

@@ -50,24 +50,12 @@ const options = {
   },
 };
 
-async function sendInvites({ emailModel, data, host }) {
-  return Promise.all(
-    data.map(async (invite) =>
-      emailModel.sendInvite({
-        email: invite.email,
-        link: `${host}/invite/${invite.id}`,
-      }),
-    ),
-  );
-}
-
 async function handler({ body }) {
   const {
     models: { Invite },
     config: {
-      globals: { invitesStatuses },
+      globals: { invitesStatuses, emailStatuses },
     },
-    emailModel,
   } = this;
 
   const invites = await Invite.transaction(async (trx) => {
@@ -83,6 +71,7 @@ async function handler({ body }) {
           resource_id: body.resourceId,
           resource_type: body.resourceType,
           status: invitesStatuses.PENDING,
+          email_status: emailStatuses.PENDING,
           email,
         }))
       : {
@@ -93,14 +82,6 @@ async function handler({ body }) {
 
     const createdInvites = await Invite.createInvites({ trx, data });
 
-    if (data.length) {
-      await sendInvites({
-        emailModel,
-        data: createdInvites,
-        host: process.env.SB_HOST,
-      });
-    }
-
     return createdInvites;
   });
 

backend.dev.yml

@@ -22,6 +22,13 @@ services:
     volumes:
       - ./storage:/data
     command: server --address 0.0.0.0:9000 --console-address 0.0.0.0:9001 /data
+  scheduler:
+    command: yarn run:dev
+    volumes:
+      - ./scheduler:/scheduler
+      - /scheduler/node_modules
+    environment:
+      DATABASE_URL: ${POSTGRES_URI}
   api:
     command: yarn run:dev
     ports:

base.dev.yml

@@ -12,6 +12,15 @@ services:
     environment:
       MINIO_ROOT_USER: ${S3_ACCESS_KEY}
       MINIO_ROOT_PASSWORD: ${S3_SECRET_KEY}
+  scheduler:
+    build:
+      context: ./scheduler
+      dockerfile: .docker/Dockerfile
+    restart: always
+    depends_on:
+      - db
+    environment:
+      HOST: ${SB_HOST}
   api:
     build:
       context: ./api

scheduler/.docker/Dockerfile

@@ -0,0 +1,7 @@
+FROM node:14-alpine
+
+WORKDIR /scheduler
+
+COPY package.json yarn.lock ./
+RUN yarn
+COPY . .

scheduler/email.js

@@ -0,0 +1,37 @@
+import mailer from 'nodemailer';
+import { DEFAULT_LANGUAGE } from './scheduler.js';
+
+export class Email {
+  constructor({ i18n }) {
+    this.t = i18n.t.bind(i18n);
+    this.transporter = mailer.createTransport({
+      pool: true,
+      host: 'smtp.gmail.com',
+      port: process.env.SMTP_PORT || 465,
+      secure: true,
+      auth: {
+        user: process.env.SB_MAIL_USER,
+        pass: process.env.SB_MAIL_PASSWORD,
+      },
+    });
+  }
+
+  static getMailMocked({ ...params }) {
+    return {
+      from: 'StudyBites',
+      ...params,
+    };
+  }
+
+  async sendMailWithLogging(params) {
+    console.log(Email.getMailMocked(params));
+  }
+
+  async sendInvite({ email, link, language = DEFAULT_LANGUAGE }) {
+    return this.sendMailWithLogging({
+      to: email,
+      subject: this.t('email:invite.subject', { lng: language }),
+      html: this.t('email:invite.html', { lng: language, link }),
+    });
+  }
+}

scheduler/locales/en/email.json

@@ -0,0 +1,18 @@
+{
+  "password_reset": {
+    "subject": "Password reset",
+    "html": "Reset password link {{link}}"
+  },
+  "password_changed": {
+    "subject": "Password changed",
+    "html": "Your password were successfully changed"
+  },
+  "email_confirmation": {
+    "subject": "Email confirmation",
+    "html": "Confirm email link {{link}}"
+  },
+  "invite": {
+    "subject": "You were invited to start learning at StudyBites",
+    "html": "Follow the link to start: {{link}}"
+  }
+}

scheduler/locales/ru/email.json

@@ -0,0 +1,18 @@
+{
+  "password_reset": {
+    "subject": "Восстановление пароля",
+    "html": "Ссылка для восстановления пароля {{link}}"
+  },
+  "password_changed": {
+    "subject": "Пароль изменен",
+    "html": "Ваш пароль был успешно изменен."
+  },
+  "email_confirmation": {
+    "subject": "Email подтверждение",
+    "html": "Подтвердите ссылку на электронную почту {{link}}"
+  },
+  "invite": {
+    "subject": "Вас пригласили начать обучение на StudyBites",
+    "html": "Пройдите по ссылке, чтобы начать: {{link}}"
+  }
+}

scheduler/package.json

@@ -0,0 +1,21 @@
+{
+  "name": "scheduler",
+  "version": "0.1.0",
+  "main": "scheduler.js",
+  "type": "module",
+  "license": "Apache-2.0",
+  "scripts": {
+    "run:dev": "yarn && nodemon scheduler.js"
+  },
+  "dependencies": {
+    "i18next": "^21.3.3",
+    "i18next-fs-backend": "^1.1.1",
+    "knex": "^0.95.11",
+    "node-cron": "^3.0.0",
+    "nodemailer": "^6.7.0",
+    "pg": "^8.7.1"
+  },
+  "devDependencies": {
+    "nodemon": "^2.0.14"
+  }
+}

scheduler/scheduler.js

@@ -0,0 +1,75 @@
+import knex from 'knex';
+import cron from 'node-cron';
+import i18next from 'i18next';
+import Backend from 'i18next-fs-backend';
+import { Email } from './email.js';
+
+export const DEFAULT_LANGUAGE = 'en';
+export const LANGUAGES_LIST = ['en', 'ru'];
+
+class Scheduler {
+  constructor({ i18n }) {
+    this.mailer = new Email({ i18n });
+  }
+
+  async start() {
+    try {
+      await this.connDB();
+      // invite job will run every one minute
+      cron.schedule('* * * * *', this.inviteJob, {});
+      console.log('scheduler started successfully');
+    } catch (e) {
+      console.log(e);
+      process.exit(1);
+    }
+  }
+
+  async connDB() {
+    this.db = knex({
+      client: 'pg',
+      connection: process.env.DATABASE_URL,
+    });
+    await this.db.raw('SELECT 1');
+  }
+
+  inviteJob = async () => {
+    try {
+      const pendingInvites = await this.db('invites').where({
+        status: 'pending',
+        email_status: 'pending',
+      });
+      pendingInvites.map(async (invite) => {
+        await this.mailer.sendInvite({
+          email: invite.email,
+          link: `${process.env.HOST}/invite/${invite.id}`,
+        });
+        await this.db('invites').where({ id: invite.id }).update({
+          email_status: 'success',
+        });
+      });
+    } catch (e) {
+      console.log('invite job failed:', e);
+    }
+  };
+}
+
+(async () => {
+  await i18next.use(Backend).init({
+    initImmediate: false,
+    lng: DEFAULT_LANGUAGE,
+    fallbackLng: DEFAULT_LANGUAGE,
+    preload: LANGUAGES_LIST,
+    ns: ['email'],
+    keySeparator: '.',
+    interpolation: {
+      escapeValue: false,
+    },
+    backend: {
+      loadPath: `locales/{{lng}}/{{ns}}.json`,
+    },
+  });
+  const scheduler = new Scheduler({
+    i18n: i18next,
+  });
+  await scheduler.start();
+})();