Convert an existing integration to a Connector

Overview

This step-by-step guide explains how to convert an existing integration into a Connector. It outlines the modifications needed to ensure that the project aligns with the new Connector requirements.

The guide covers various aspects such as the Connector specification file (connect.yaml), determining the appropriate application type, implementing the proper folder structure, and constructing the necessary automation scripts for managing extensions and subscriptions.

Configure connect.yaml

To convert an existing repository to a valid Connector you must create and configure a connect.yaml file. connect.yaml is required and is the starting point of each Connector repository.

connect.yaml contains the descriptions and configurations of each application to be deployed, and is used to publish and deploy the Connector.

Example connect.yaml file

You can use the following example connect.yaml file as a reference to create your own.

Example connect.yaml fileyaml

deployAs:
  - name: service_app_name
    applicationType: service
    endpoint: /service
    scripts:
      postDeploy: npm run connector:post-deploy
      preUndeploy: npm run connector:pre-undeploy
    configuration:
      standardConfiguration:
        - key: CTP_PROJECT_KEY
          description: Project key of the commercetools Composable Commerce Project
          required: true
          default: 'default-key'
      securedConfiguration:
        - key: CTP_CLIENT_ID
          description: client_id of an API Client for the commercetools Composable Commerce Project
          required: true
  - name: job_app_name
    applicationType: job
    endpoint: /job
    properties:
      schedule: '*/5 * * * *'
    configuration:
      standardConfiguration:
        - key: CTP_PROJECT_KEY
          description: Project key of the commercetools Composable Commerce Project
          required: true
      securedConfiguration:
        - key: CTP_CLIENT_ID
          description: client_id of an API Client for the commercetools Composable Commerce Project
          required: true
inheritAs:
  configuration:
    securedConfiguration:
      - key: GLOBAL_SECURED_CONFIGURATION
        description: Secured configuration that is applied to all applications
        required: true
    standardConfiguration:
      - key: GLOBAL_STANDARD_CONFIGURATION
        description: Standard configuration that is applied to all applications
        required: true

See the following table for explanations of each attribute.

Key	Required	Description
`deployAs`	Yes	A root key of the file containing an array of the applications that we want to deploy in our Connector. In this file example, two applications named `service_app_name` and `job_app_name` are deployed. The name must match the folder for the application in your repository.
`name`	Yes	Identifier of the application deployment. This is important as the deployment's output URL, topic, and schedule are fetched based on this reference. `name` has a maximum length of 256 characters and can only contain the letters A to Z in lowercase or uppercase, numbers, underscores (`_`), and the hyphen-minus (`-`).
`applicationType`	Yes	The type of application to deploy. Connectors currently support the following application types: `service`, `event`, `job`, `merchant-center-custom-application`, and `assets`.
`endpoint`	Yes (service, job, event applications)	The `endpoint` naming used by the Deployment URL. The URL is constructed using the format `{connect-provided-url}/{endpoint}` (for example: `https://service-11111111-1111-1111-1111-111111111111.europe-west1.gcp.commercetools.app/service`) `endpoint` can optionally start with `/` and has a maximum length of 256 characters containing the letters A to Z in lowercase or uppercase, numbers, underscores (`_`), and the hyphen-minus (`-`). `endpoint` is not required if the `applicationType` is `merchant-center-custom-application` or `assets`.
`properties.schedule`	Yes (job type applications)	This configuration is only required for `job` applications. As it will work as a `cron job` it is important to specify the execution schedule.
`scripts`	No	Displays the configuration for the Connector's scripts. You will need this field if you need to create and use commercetools API Extensions and Subscriptions.
`configuration`	No	An object of configurations to be used in the Connector as schema validation. This is an array containing `standardConfiguration` and `securedConfiguration`.
`inheritAs`	No	A root key of the file that is optional and contains configurations that are shared with all applications.

After gaining an understanding of the required application types for the Connector and creating connect.yaml, it is essential to adhere to a project structure that aligns with it.

Structure your project

In the context of Connect, each application is treated independently and it is necessary to isolate each application in a separate folder, as each one will be provisioned in a slightly different manner based on its application type.

Each folder must contain the value specified in the name attribute.

Using the previous connect.yaml example, we should have the following directory structure:

myconnector/
├── service_app_name/
│   └──src
│      └──  index.js
│   ├── package-lock.json
│   └── package.json
├── job_app_name/
│   └──src
│      └──  index.js
│   ├── package-lock.json
│   └── package.json
└── connect.yaml

Choose an application type

Connect supports the following types of applications:

service: perform specific actions using API Extensions or webhooks to other systems. A possible use case is to validate newly created resources, calculate custom shipping costs for a cart, and add mandatory items.
event: receive events and perform actions asynchronously using Subscriptions. You can use event applications to notify your customers after a successful payment or if a product is back in stock.
job: schedule tasks using cron expressions to run job applications on a periodic basis, such as updating a resource every minute, generating a nightly report, or sending an automated weekly email newsletter.
merchant-center-custom-application: create Custom Applications to extend the functionality of the Merchant Center.
assets: host static assets with CDN capabilities.

Implement Connect applications

Every application receives the necessary configuration as defined in connect.yaml, which is provided through environment variables.

Additionally, each Connect application must ensure that it exposes an HTTP server at 8080, encompassing all the required integration endpoints, as in the following examples:

Service

import express, { Request, Response } from 'express';
import bodyParser from 'body-parser';

const app = express();
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));

app.post('/service', async (req: Request, res: Response) => {
  const action = req.body;
  console.info('New action received', action);

  // handle business logic
  const additionalActions = [];
  // build additional resource update action

  res.status(200).json({ actions: additionalActions });
});

Event

import express, { Request, Response } from 'express';
import bodyParser from 'body-parser';

const app = express();
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));

app.post('/event', async (req: Request, res: Response) => {
  const event = req.body;
  console.info('New event received', event);

  // handle business logic
  // ex: notify user product back in stock

  res.status(200).send();
});

Job

import express, { Request, Response } from 'express';
import bodyParser from 'body-parser';

const app = express();

app.post('/job', async (req: Request, res: Response) => {
  const event = req.body;
  console.info('New event received', event);

  // handle business logic
  // ex: build report, send email

  res.status(200).send();
});

package.json

You must include the following scripts in package.json.

Name	Description
`gcp-build`	Automates the build process of the project to generate production-ready code.
`start`	The entry point of the application, responsible for initializing the server listening on port 8080.

"scripts": {
    "gcp-build": "tsc",
    "start": "node build/index.js"
}

Adding automation scripts

For automating configurations for Composable Commerce, for example, for Subscriptions or for creating Custom Types, see Adding automation scripts.

Testing your Connect application

It is mandatory to include tests for your Connect application. This is to ensure that your application codebase has a good level of quality to guarantee proper functionality and maintainability.

We recommend using a tool like Jest, which allows you to use multiple useful assertions and mocks, and gather code coverage.

// isInteger.js
const isInteger = (value) => !isNaN(parseInt(value, 10));

export { isInteger };

// __tests__/isInteger.spec.js
import { isInteger } from './isInteger';

describe('isInteger function', () => {
  test('it should check if value is an integer number', () => {
    expect(isInteger(-1)).toEqual(true);
    expect(isInteger(0)).toEqual(true);
    expect(isInteger(1).toEqual(true));
    expect(isInteger(1.5).toEqual(false));
  });
});

npm test

PASS  __tests__/isInteger.spec.js
  isInteger function
    ✓ it should check if value is an integer number (2ms)

Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        0.764s, estimated 1s