How to install Flex Gateway on Ubuntu Server (Local Mode)

In our previous post we’ve learnt how to install Flex Gateway on an Ubuntu Server in Connected Mode. Today, we will learn how to install Flex Gateway on an Ubuntu server in local mode. We will see how we can manage the Flex Gateway locally, using configuration files. We’ll install it step-by-step, then test it using a small Node.js REST API with a /hello endpoint. Let’s dive in.

Prerequisites

To follow this tutorial we’ll need:

• An Ubuntu Server - In this tutorial we’ll use Ubuntu Server version 24.04 LTS running on an AWS EC2 instance.
• A non-mule API running to test the Flex GW - If you don’t have an API for testing check out these posts to quickly get one:

How to Create a REST API with Spring Boot
How to Create a REST API with NodeJS
How to Create a REST API with Python

In this example, we’ll use this NodeJS REST API deployed in the same server as the Flex Gateway, in port 3000. This way, when we run the following command from the Ubuntu server:

curl http://localhost:3000/hello

We get the response

{"message":"Hello World from NodeJS!"}

Install Flex Gateway

Add the Mulesoft Repository

Run the following commands to add MuleSoft’s repository and install required dependencies:

curl -XGET -L https://flex-packages.anypoint.mulesoft.com/ubuntu/pubkey.gpg | sudo apt-key add - 
echo "deb https://flex-packages.anypoint.mulesoft.com/ubuntu $(lsb_release -cs) main" \ | sudo tee /etc/apt/sources.list.d/mulesoft.list

Install Flex Gateway

Run the installation command:

sudo apt-get update
sudo apt-get install -y flex-gateway

Verify the installation

Check the version of Flex GW

flexctl version

(Don’t worry about the error messages - those are normal, as we still haven’t start the Flex GW)

Register and Configure Flex Gateway

There are three options for registering Flex Gateway in Local Mode:

• Using a username and password
• Using a Connected App
• Using a Token: We can also use a registration token generated by the Runtime Manager UI. The token is valid for four hours.

In this tutorial, we’ll use the Token generated by the Runtime Manager UI. For that, go to Runtime Manager → Flex Gateway and click Add Gateway. In the options for deployment choose Linux and then Ubuntu/Debian as the OS. We will get a set of instructions.

From the Register Gateway step, copy the token generated. We’ll use it for the local registration.

Run Local Registration

Back to our Ubuntu server run the command:

sudo flexctl registration create \
--token=b74cd23f-613e-485c-9ee6-9dc618e54951 \
--organization=bba812be-8714-450b-ae1c-b2a418836c06 \
--connected=false \
--output-directory=/usr/local/share/mulesoft/flex-gateway/conf.d \
<gateway-name>

Where:

• --token is the token we’ve copied in the previous step
• <gateway-name> is the descriptive name for our Flex GW
• --organization=[YOUR_BUSINESS_GROUP_ID] is the ID of the Business Group where we’ll be deploying our API instances
• --connected=false tells Flex GW that the installation will be done in Local mode
• --output-directory - Specifies the path with our Ubuntu server where Flex GW will place the output of the command

Start the Flex Gateway Service

Once the installation is ready, we’ll enable the flex gateway as a Linux service and start it:

sudo systemctl enable flex-gateway
sudo systemctl start flex-gateway

Verify the installation

To verify that everything went we’ll check the status of the service and the logs

Check the Status

Run the systemctl command:

sudo systemctl status flex-gateway

You should see the service active and green

View Logs

It’s also a good idea to check the logs of the service with the command:

journalctl -u flex-gateway --no-pager --lines=50

Publish an API

Now it’s time to deploy an API instance in front of our NodeJS REST API.

In local mode, to publish an API in front of our NodeJS API we need to create a yaml file. For that, first, go to the folder in the system /etc/mulesoft/flex-gateway/conf.d/custom. It might be possible that, the first time you publish an API, the custom directory does not exist. If that’s the case create it.

From that path, create a yaml file, we’ll call it config-nodejs-api.yaml

vi config-nodejs-api.yaml

And paste the following content:

apiVersion: gateway.mulesoft.com/v1alpha1
kind: ApiInstance
metadata:
  name: hello-nodejs-api
spec:
  address: http://0.0.0.0:80
  services:
    nodejs-api:
      address: http://localhost:3000/
      routes:
        - rules:
            - path: /nodejs(/.*)

With this configuration:

• Our Flex Gateway will be listening on any IP address and port 80 for this API
• The path rule will create an endpoint /nodejs and forward all traffic to this path and any other path relative to /nodejs (that is /nodejs/YOUR_PATH) to our own server on port 3000 with the relative path added. In other words

http://[YOUR_FGW_HOST]:80/nodejs/[YOUR_PATH] --> http://localhost:3000/[YOUR_PATH]

Save the file and automatically Flex Gateway will create the API instance. Give it a few seconds and test it from the same server with:

curl http://localhost/nodejs/hello

And test it, as well, from outside the server using the public DNS of our server:

Secure the API with Basic Authentication and Rate Limiting

So far so good. Our flex gateway is working and routing requests. Now, let’s see how to apply policies to this API in local mode. For that we’ll add the policies section to the yaml config file we created in the previous section (config-nodejs-api.yaml)

apiVersion: gateway.mulesoft.com/v1alpha1
kind: ApiInstance
metadata:
  name: hello-nodejs-api
spec:
  address: http://0.0.0.0:80
  services:
    nodejs-api:
      address: http://localhost:3000/
      routes:
        - rules:
            - path: /nodejs(/.*)

  policies:
    - policyRef:
        name: http-basic-authentication-flex
      config:
        username: [YOUR_USERNAME]
        password: [YOUR_PASSWORD]
    - policyRef:
        name: rate-limiting-flex
      config:
        exposeHeaders: true
        rateLimits:
          - maximumRequests: 3
            timePeriodInMilliseconds: 60000
        keySelector: "#[attributes.queryParams['identifier']]"

With that we’ll we adding two policies:

• Basic Authentication - requests will have to include the username and password specified in the config file
• Rate Limiting - Maximum of 3 requests per minute will be allowed to be forwarded to our back end API.

Save the file and the policies will be applied automatically. Now, if you repeat the previous test you’ll get an error - not authorized. Try again providing username and password.

Internally:

curl http://localhost/nodejs/hello -u [YOUR_USERNAME]

You’ll be prompted to provide the password. It should work now.

Externally - Repeat the same request providing username and password from outside the Server.

Repeat the same request another 3 times (in less than a minute) and then you’ll get the 429 error - Too many requests. That means the rate limiting is working