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The configuration provider add-on helps you to create groups of environment variables that you can share with multiple applications.
Let’s take an example with 2 Node.js applications exposing some REST APIs:
shipping-api application needs the following environment variables:
payment-api application needs the following environment variables:
As you can see, we had to define
USER_API_HOST in both applications with the same value.
If we ever need to change these values, we’ll have to apply the updates in both apps and restart them.
NOTE: This is a simple example, but we could have more than just 2 microservices and more than just 2 common variables.
To simplify this process, we will create a configuration provider add-on. It will allow us to define those common variables in one place and inject them in our 2 applications.
Think of a configuration provider as a way to group a set of environment variables and share them with any application.
If a variable is defined in a configuration provider and also in the application, the value defined in the application wins.
How to create a config provider
In the console, go to the organisation where you have your applications.
- Click on “Create…" and then on “an add-on”
- You will see a list of add-ons, select “Configuration provider”
- Select the first plan and click on “Next”
- Toggle the “Link” for each application you need and then on “Next”
- Define a name and click on “Next”
Once you have your configuration provider, you can set the variables in the form. You can find out more about rules and format in this page.
NOTE: At any point, you can link/unlink an application from the configuration provider by going to the app’s “Service dependencies” page.
Details and behaviour
- As with any other add-on, you can only link a configuration provider to applications that are in the same organisation.
- Variables defined directly in the application override the ones injected from the configuration provider.
- When you update the variables of a configuration provider, all applications linked to it will be automatically restarted.
- You can create multiple configuration providers in your organisation and link them to different applications.
This add-on is completely free. No fee will be invoiced to you while using this kind of add-on.