poc-express-unleash

🚀 A proof of concept for using Unleash feature flag service with express

• Unleash an open-source software for managing feature flags for trunk-based development.
• Documentation for Getting started with Unleash could be found here
• Docker compose file and setup can be found here

Table of Contents

• poc-express-unleash
  • Table of Contents
  • Getting Started
    • Docker-compose
    • Setting up Unleash Proxy
      • User accounts
  • Snake Service
    • Adding a Project
    • Adding a feature flag
    • Rebuild the image
  • Common issues
    • Work locally with this repo
  • Additional Links
  • Thoughts
  • LICENSE

Getting Started

Docker-compose

🐳 Make sure that the docker service is up and running.

1. Clone the unleash-docker repository. git clone git@github.com:murshidazher/poc-express-unleash.git
2. Run docker-compose build in repository root folder.
3. Run docker-compose up in repository root folder.

Setting up Unleash Proxy

Documentation could be found here.

An unleash proxy is need as a way for client-sdks to consume feature flags in the application.

• Open the browser and go to localhost:4242

• Add the default admin credentials and login

• Go to Configure -> API access -> Configure the proxy

• Create a token for the unleash-proxy and add it to the docker-compose.

  Example screen shot for configured client key

  

• docker-compose up proxy to restart the proxy.

• Verify that the proxy is running

  curl -H "Content-Type: application/json" \
     -H "Authorization: proxy-client-key" \
     -X GET \
     http://localhost:3000/proxy

  Example curl request for fetching flags using proxy key

  

User accounts

• Once started up, you'll have a user with
  • username: admin
  • password: unleash4all

Snake Service

An example small api to fetch snake names

• By default, the service only returns a single snake name.

• A new product outline has come in to add a new modification to send multiple snake names instead of one.

• Since you're doing a truck-based development you need to wrap the changes inside a feature flag.

• We will be using the node.js SDK, but you can use whatever the SDK you prefer. The list of available SDK are here.

  Default response of snake-name api

  

Adding a Project

💡 Open-source version only get the default project, we cant create more projects. 😞

• Select the default project.

Adding a feature flag

🎏 Check out the feature flags documentation for the types of feature flag that could be created.

• You can also use the unleash-client-proxy with node-fetch module to connect to the proxy instead of connecting to the server directly using API key.
• But this example uses the unleash-client SDK to directly connect since the communication would be amount services.

For this example, lets create a flag called fflag-get-three-snake-names

using the shell

```sh curl --location --request POST 'http://localhost:3000/api/admin/projects/default/features' \ --header 'Authorization: proxy-client-key' \ --header 'Content-Type: application/json' \ --data-raw '{ "type": "operational", "name": "fflag-get-three-snake-names", "description": "PO - Return three random snake names instead of a single snake name in response", "impressionData": true }' ```

using the UI

• Enable the flag in development environment and gradual rollout to 50%

  Enable the flag

  
  Requesting fflag with 50% gradual rollout

  

• After feature flag response

Getting the new feature

Rebuild the image

You need to rebuild the docker-image after any changes,

docker-compose build snake-service
docker-compose up snake-service

Common issues

Work locally with this repo

🌟 This section is adapted from unleash-docker docs.

Start by cloning this repository.

The unleash community has set up docker-compose to start postgres and the unleash server together. This makes it really fast to start up unleash locally without setting up a database or node.

docker-compose build
docker-compose up

On some computers, the database won't start in time for Unleash the first time you run this. If Unleash fails to reach the database, docker-compose restart web usually resolves the issue.

Additional Links

• To give context to unleash, refer to this section of the documentation.
• For custom auth strategy, example if you need to enable a feature for QA users with some email address. Refer to this section of the documentation
• For custom redis storage, refer to this section fo the documentation and client-proxy-sdk.

Thoughts

My thoughts on Unleash,

• 🟢 Great interface and easy setup
• 🟡 Would've been great if there was an extendible db setup other than PostgreSQL (ex. MongoDB)
• 🔴 Pegging the number of project to 1 which is only the default project. (Open-source)
• 🔴 The user access control feature for individual projects is only available for paid versions. (Open-source)

LICENSE

2023 © Unleash & Murshid Azher.