Initial commit

.gitignore

+.env
+/templates/
+
+# Dependency directories
+node_modules/
+
+# Logs
+logs/
+*.log
+npm-debug.log*
+
+# Optional npm cache directory
+.npm/
+
+# Optional REPL history
+.node_repl_history/

.gitlab-ci.yml

+services:
+  - docker:dind
+
+variables:
+  IMAGE_SNAPSHOT: $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA
+  IMAGE: $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_NAME
+  IMAGE_LATEST: $CI_REGISTRY_IMAGE:latest
+
+stages:
+  - build
+  - release
+
+before_script:
+  - docker version
+  - docker info
+  - docker login -u gitlab-ci-token -p $CI_JOB_TOKEN $CI_REGISTRY
+
+build:
+  stage: build
+  script:
+    - docker build --pull -t $IMAGE_SNAPSHOT .
+    - docker push $IMAGE_SNAPSHOT
+  tags:
+    - dind
+
+release:
+  stage: release
+  variables:
+    GIT_STRATEGY: none
+  script:
+    - docker pull $IMAGE_SNAPSHOT
+    - docker tag $IMAGE_SNAPSHOT $IMAGE
+    - docker push $IMAGE
+  tags:
+    - dind
+
+release:latest:
+  stage: release
+  variables:
+    GIT_STRATEGY: none
+  script:
+    - docker pull $IMAGE_SNAPSHOT
+    - docker tag $IMAGE_SNAPSHOT $IMAGE_LATEST
+    - docker push $IMAGE_LATEST
+  when: manual
+  tags:
+    - dind
+  only:
+    - master

Dockerfile

+FROM node:10-alpine
+
+MAINTAINER Vadym Gidulian <vadym.gidulian@gvia.group>
+
+COPY package.json yarn.lock /app/
+COPY src/ /app/src/
+
+VOLUME /app/templates
+
+WORKDIR /app
+
+RUN yarn install --production &&\
+	yarn cache clean
+
+CMD ["node", "src"]
+EXPOSE 80

docker-compose.yml

+version: '3'
+
+services:
+  server:
+    build: .
+    volumes:
+      - .:/app
+      - ./templates:/app/templates
+    entrypoint: sh
+    command: -c "yarn && npx nodemon src"
+    environment:
+      CORS_ALLOW_ORIGIN: $CORS_ALLOW_ORIGIN
+      SMTP_HOST: $SMTP_HOST
+      SMTP_PORT: $SMTP_PORT
+      SMTP_SECURE: $SMTP_SECURE
+      SMTP_USER: $SMTP_USER
+      SMTP_PASSWORD: $SMTP_PASSWORD

package.json

+{
+	"name":    "@gviagroup/service-mailer",
+	"version": "0.1.0",
+
+	"dependencies": {
+		"express":         "^4.16.3",
+		"nodemailer":      "^4.6.8",
+		"@gviagroup/jsvv": "~0.6.0"
+	},
+	"devDependencies": {
+		"nodemon": "^1.18.4"
+	}
+}

src/index.js

+'use strict';
+
+const express     = require('express');
+const jsvv        = require('@gviagroup/jsvv');
+const mailerModel = require('./models/mailer');
+
+const requestSchema      = require('./schemas/request');
+const templateNameSchema = require('./schemas/template-name');
+
+const CORS_ALLOW_ORIGIN = process.env.CORS_ALLOW_ORIGIN || '*';
+
+const app = express();
+
+app.use(express.json({
+	limit: '1mb'
+}));
+app.use((req, res, next) => {
+	res.header('Access-Control-Allow-Origin', CORS_ALLOW_ORIGIN);
+	res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept');
+	res.header('Access-Control-Allow-Methods', 'OPTIONS, POST');
+	next();
+});
+
+app.post('/:template', async (req, res) => {
+	try {
+		req.params.template = jsvv(req.params.template, templateNameSchema);
+		req.body            = jsvv(req.body, requestSchema);
+	} catch (e) {
+		return res.status(400).send(e.message);
+	}
+	
+	try {
+		res.status(200).send(await mailerModel.sendMessage(req.params.template, req.body));
+	} catch (e) {
+		console.error(e);
+		res.status(500).send();
+	}
+	
+});
+
+app.listen(80, () => {
+	console.log('Server is started.');
+});

src/models/mailer.js

+'use strict';
+
+['SMTP_HOST', 'SMTP_PORT', 'SMTP_USER', 'SMTP_PASSWORD'].forEach(varname => {
+	if (!process.env[varname]) {
+		console.error(`Environment variable ${varname} is not defined!`);
+		process.exit(1);
+	}
+});
+
+const {promisify}    = require('util');
+const nodemailer     = require('nodemailer');
+const templatesModel = require('./templates');
+
+const SMTP_HOST         = process.env.SMTP_HOST;
+const SMTP_PORT         = process.env.SMTP_PORT;
+const SMTP_SECURE       = process.env.SMTP_SECURE || false;
+const SMTP_USER         = process.env.SMTP_USER;
+const SMTP_PASSWORD     = process.env.SMTP_PASSWORD;
+const SMTP_SENDER       = process.env.SMTP_SENDER || SMTP_USER;
+
+templatesModel.prepareTemplates();
+
+const transporter = nodemailer.createTransport({
+	host:   SMTP_HOST,
+	port:   SMTP_PORT,
+	secure: SMTP_SECURE,
+	auth: {
+		user: SMTP_USER,
+		pass: SMTP_PASSWORD
+	},
+	pool: true
+});
+transporter.verify((err) => {
+	if (err) {
+		console.error(err);
+		process.exit(1);
+	}
+	console.log('SMTP server is ready.');
+});
+const sendMail = promisify(transporter.sendMail).bind(transporter);
+
+module.exports = {
+	async sendMessage(template, request) {
+		const message = templatesModel.getTemplate(template).replace(/{{(.+?)}}/g, (match, name) => request.vars && request.vars[name] || '');
+		
+		const mailer = {
+			from:    SMTP_SENDER,
+			to:      request.to,
+			subject: request.subject,
+			html:    message
+		};
+		
+		const {messageId, accepted, rejected} = await sendMail(mailer);
+		
+		return {messageId, accepted, rejected};
+	}
+};

src/models/templates.js

+'use strict';
+
+const fs = require('fs');
+
+const TEMPLATES_DIR = '/app/templates';
+
+const templates = {};
+
+module.exports = {
+	prepareTemplates() {
+		try {
+			if (fs.statSync(TEMPLATES_DIR)) {
+				const filenames = fs.readdirSync(TEMPLATES_DIR);
+				filenames.forEach(filename => {
+					templates[filename] = fs.readFileSync(`${TEMPLATES_DIR}/${filename}`, {encoding: 'utf-8'});
+				});
+			}
+			
+			console.log(`Loaded templates: ${Object.keys(templates).map(name => `"${name}"`).join(', ')}`);
+		} catch (e) {
+			console.error(e);
+			process.exit(1);
+		}
+	},
+	
+	getTemplate(name) {
+		return templates[name] || '';
+	}
+};

src/schemas/primitives/string-required.js

+'use strict';
+
+module.exports = {
+	type:       String,
+	required:   true,
+	minLength:  1,
+	transforms: [String.prototype.trim]
+};

src/schemas/request.js

+'use strict';
+
+const stringRequiredSchema = require('./primitives/string-required');
+
+module.exports = {
+	type:     Object,
+	required: true,
+	properties: {
+		to:      stringRequiredSchema,
+		subject: stringRequiredSchema,
+		vars: {
+			type: Object
+		}
+	}
+};

src/schemas/template-name.js

+'use strict';
+
+const stringRequiredSchema = require('./primitives/string-required');
+
+module.exports = stringRequiredSchema;