How to select proxy and non-proxy configurations for connectors depending on the deployment environment (Mule 4.x)

DESCRIPTION

You have a Mule Application that connects to external systems using connectors such as HTTP or SFTP. Usually, when deploying applications to different environments (Dev, QA, or Prod) you need to reach different endpoints, and depending on the environment, sometimes you require to go through a proxy or not. 

In this article, we'll cover how to programmatically choose between proxied and non-proxied configurations reducing the number of code changes required. 

STEPS TO FOLLOW

In this example, we'll use the HTTP Connector defining a proxied configuration and a not proxied one for HTTP Requests (outbound), and we'll set the not proxied to be used in "dev" and the proxied one to be used in "prod".
In this guide, we'll use concepts from Configuring Properties documentation.

1- Define your connector configurations.

EG.

<http:request-config name="HTTP_Request_configuration_proxy" doc:name="HTTP Request configuration" >
<http:request-connection host="yourHost" port="yourPort" >
<http:proxy-config >
<http:proxy host="yourProxyHost" port="yourProxyPort" />
</http:proxy-config>
</http:request-connection>
</http:request-config>

<http:request-config name="HTTP_Request_configuration" doc:name="HTTP Request configuration" >
<http:request-connection host="yourHost" port="yourPort" />
</http:request-config>

2- Create the properties files for your "dev" and "prod" environments and locate them under "src/main/resources". 

In those files, we'll set the property "httpconfig" as the name of the HTTP Configuration we want to use in that environment.

EG.

File name: dev.properties

httpconfig=HTTP_Request_configuration

File name: prod.properties

httpconfig=HTTP_Request_configuration_proxy

3- Create a global property that you will use to select the properties file according to the environment.

EG.

<global-property doc:name="Global Property" name="env" value="dev" />

You can either hardcode its value in the component or set it dynamically through System properties or Environment variables.

4- Create a configuration properties element and set the naming convention for your properties files. 

EG.

<configuration-properties doc:name="Configuration properties" file="${env}.properties" />

5- Configure the HTTP Request operation to pick the right HTTP configuration, based on the value of the property "httpconfig" in your properties files.

EG.

<http:request method="GET" doc:name="Request" config-ref="${httpconfig}" path="/"/>

6- Run the application.

Note 1:

If you deploy the application setting "env" as "dev" it will execute the HTTP Request operation using a non-proxy configuration, alternatively, if you set it as "prod" it will use the one with the proxy.

Note 2:

This kind of process can be followed for different connectors and can be tailored according to your needs for example using additional properties to resolve each configuration or using secure properties if needed.

You can find a sample application attached to this article where the steps described were applied. Make sure to modify the project to use your host, port, and proxy settings in case you want to test it. 

Disclaimer: This solution provides a suggestion that should be considered in conjunction with your specific use case and requirements and does not represent a complete solution for all circumstances.