Jun 4, 2020
Creating a Maintenance mode for your API Gateway with Terraform
In my previous blog post, I went through how to create a maintenance mode page for your application, and how to implement it using Terraform and github pages. But the website is just one part of an Application, and often there’s also a public (or private) API that also needs to have a maintenance mode. Let’s see how we can do that using Terraform on API Gateway.
As previously mentioned, we host all of our infrastructure on AWS, with a clear separation between the Application and the API:
Beyond the requirements for our webpage maintenance mode, we had one new one: When the API is in maintenance it should return “503 Service Unavailable” response with an informative message. This led us led us to the following solution:
Based on that, let’s see the Terraform code in action.
Looking at the code you are able to see that we are using ANY method together with “{proxy+}” to achieve the ability to cover all resources with a simple configuration, and using the response template to generate the “503 Service Unavailable” response with a clear message to the end user.
Now using a custom domain we can control the maintenance mode, so the base path mapping will either point to the real API and in case of a maintenance mode it will point to the mocked API.
Also in AWS, we want to ensure that Route53 is pointing in the custom domain we’ve created. As opposed to the application maintenance mode, here our custom domain switches on and off our maintenance mode and not our DNS record.
Now that our system is all configured, all I have to do is change the Terraform variable of the maintenance mode to be true/false and deploy the environment (in our case via the env0 UI).
The complete template source code can be found in this github repo which includes all the Terraform code. We hope you find this useful, or get other ideas for more ways to use Terraform for your deployment workflows.
env0 lets your team manage their own environments in AWS, Azure and Google, governed by your policies and with complete visibility & cost management. You can learn more about env0 here and you can also try it out yourself. Feel free to drop us your thoughts below!
