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Create and deploy a Node.js Backend For Frontend (BFF) using Express

We have similar patterns available for Swift, Java Spring, and Java Liberty as well!

In this code pattern, you will create a Backend for Frontend (BFF) web service using Express in Node.js, matching a RESTful API documented in Swagger.

A BFF can be used to elegantly expose complex backend systems to multiple client-facing platforms, such as iOS and the web, without building a monolithic API that attempts to serve all clients equally. Different types of clients require different types of user experiences, and having a backend API tightly coupled to each specific user experience actually makes for a much more loosely coupled system overall. This pattern helps frontend teams iterate on features faster by giving them more control over the APIs they interact with, without affecting the user experience or development team driving a sister frontend.

When you have completed this code pattern, you will understand how to:

• Build out the Backend for Frontend (BFF) architecture pattern
• Deploy to Kubernetes, Cloud Foundry or a DevOps Pipeline
• Operate an application with monitoring and distributed trace
• Connect to provisioned services

Video

Learn more about the Backend for Frontend pattern in this tech talk:

Steps

As an alternative to the steps below, you can create this project as a starter kit on IBM Cloud, which automatically provisions required services, and injects service credentials into a custom fork of this pattern. Then, you can skip directly to step 3 below.

1. Install development tools
2. Configuration
3. Run

1. Install development tools

Local Development Tools Setup

• Install the latest NodeJS 6+ LTS version.

IBM Cloud development tools setup

1. Install IBM Cloud Developer Tools on your machine
2. Install the plugin with: ibmcloud plugin install dev -r "IBM Cloud"

2. Configuration

The project contains IBM Cloud specific files that are used to deploy the application as part of an IBM Cloud DevOps flow. The .bluemix directory contains files used to define the IBM Cloud toolchain and pipeline for your application. The manifest.yml file specifies the name of your application in IBM Cloud, the timeout value during deployment, and which services to bind to.

Service credentials are taken from the VCAP_SERVICES environment variable if running IBM Cloud Foundry, from individual environment variables per service if running on IBM Cloud Container Service (see ./server/config/mappings.json), or from a config file if running locally, named ./server/config/localdev-config.js.

3. Run

Using IBM Cloud development CLI

The IBM Cloud development plugin makes it easy to compile and run your application if you do not have all of the tools installed on your computer yet. Your application will be compiled with Docker containers. To compile and run your app, run:

ibmcloud dev build
ibmcloud dev run

Using your local development environment

Endpoints

Your application is running at: http://localhost:3000/ in your browser.

• Your Swagger UI is running on: /explorer
• Your Swagger definition is running on: /swagger/api
• Health endpoint: /appmetrics-dash

Session Store

You may see this warning when running ibmcloud dev run:

Warning: connect.session() MemoryStore is not
designed for a production environment, as it will leak
memory, and will not scale past a single process.

When deploying to production, it is best practice to configure sessions to be stored in an external persistence service.

Troubleshooting

Using IBM Cloud development CLI

To build and debug your app, run:

ibmcloud dev build --debug
ibmcloud dev debug

License

This code pattern is licensed under the Apache License, Version 2. Separate third-party code objects invoked within this code pattern are licensed by their respective providers pursuant to their own separate licenses. Contributions are subject to the Developer Certificate of Origin, Version 1.1 and the Apache License, Version 2.

Apache License FAQ