Concepts
Stages in API Gateway represent different versions or environments of your API, such as Development, Testing, or Production. Each stage has its settings, including stage variables, caching parameters, and logging settings. When you deploy an API, you deploy it to a stage.
Here’s an example of how stages might be used:
- Development Stage: For developers to test new features.
- Testing Stage: For QA to perform testing.
- Production Stage: The live version of your API used by end-users.
You can manage access to these stages by using resource policies. For instance, you might restrict access to the development stage to only specific IP addresses.
Stage Variables
Stage variables allow you to store environment-specific data that can be used in your API Gateway configuration. You might use a stage variable to specify different endpoint URLs for services your API relies on depending on the stage.
Example:
{
“Variables”: {
“functionArn”: “arn:aws:lambda:REGION:ACCOUNT_ID:function:FUNCTION_NAME”
}
}
Here, you might change the functionArn variable for each stage to point to a different AWS Lambda function.
Stage Deployment
When you deploy to a stage, you are essentially taking a snapshot of your APIs resources and methods at that point in time. Deploying immutable changes ensures that different stages do not affect each other.
Custom Domains
Custom domains are used to map a domain name (like api.example.com) to your API Gateway API so that it has a branded and user-friendly URL instead of the default endpoint URL provided by API Gateway.
Here’s how you would set up a custom domain:
- Purchase and setup a domain name through a domain registrar.
- Obtain an SSL/TLS certificate for your domain using AWS Certificate Manager or another certificate provider.
- Set up a custom domain in API Gateway by specifying the domain name and binding the SSL/TLS certificate.
- Create a base path mapping, which connects the custom domain to a specific deployment stage of your API.
Here’s the sample AWS CLI command to set up a custom domain name for an API stage:
aws apigateway create-domain-name –domain-name ‘api.example.com’ –certificate-arn ‘arn:aws:acm:REGION:ACCOUNT-ID:certificate/CERTIFICATE-ID’
Once you have set up the custom domain, you typically configure a DNS record (such as a CNAME or an ALIAS record) in your DNS provider to point to the CloudFront distribution that API Gateway creates for your custom domain.
Integration Example
Suppose you have an API with the following stages:
dev.api.example.comfor developmenttest.api.example.comfor testingapi.example.comfor production
Each of these subdomains would be set up as custom domains in API Gateway, and each custom domain would be tied to the corresponding API Gateway stage.
The benefit of using stages and custom domains is the ability to easily manage, test, and release different versions of the API. You can experiment with new features in development without affecting production API users. Moreover, custom domains provide a professional and branded API experience for your users.
Summary
When combining the use of stages and custom domains, you get a powerful way to manage API lifecycle, from development to production. Stages let you deploy, test, and iterate on your API, whereas custom domains give your API a branded and easy-to-remember URL. Together, they offer a seamless workflow for managing APIs at scale.
Answer the Questions in Comment Section
True or False: An API Gateway Stage is a snapshot of the API that can be invoked by the users.
- Answer: True
An API Gateway Stage represents a snapshot of your API that can be deployed and subsequently invoked by the user. It acts as a stable endpoint for a particular version of your API.
True or False: You cannot access the same AWS Lambda function across different stages in API Gateway.
- Answer: False
You can access the same AWS Lambda function across different stages in API Gateway. Stages can point to different configurations of the same Lambda function.
True or False: Once you create a custom domain name in API Gateway, you can use it for multiple services across AWS.
- Answer: False
A custom domain name in API Gateway is specifically associated with the API Gateway service and can’t be used for multiple services across AWS without some form of redirection or proxy in place.
Which of the following are parts of an API Gateway Stage configuration? (Select TWO)
- a. Stage variables
- b. Usage plans
- c. Client Certificates
- d. Data encryption keys
- e. Throttling settings
Answer: a, c
Stage variables and client certificates are both parts of an API Gateway Stage configuration. Stage variables allow for configuration tweaks and client certificates can be used for backend authentication.
True or False: API Gateway does not allow you to define per-method throttling settings at the stage level.
- Answer: False
API Gateway does allow you to define per-method throttling settings at the stage level, providing granular control over the rate and burst limits for each method.
What does a custom domain name provide in API Gateway? (Select ONE)
- a. Direct access to a backend Lambda function
- b. Custom URL endpoint for the API
- c. An SSL/TLS certificate for the API
- d. Enhanced API monitoring
Answer: b
A custom domain name provides a custom URL endpoint for the API, making it more user-friendly and consistent for consumers.
True or False: Stages in API Gateway are immutable and cannot be changed after deployment.
- Answer: False
Stages in API Gateway are not immutable; you can update the stage configuration and deploy new code to stages as necessary.
True or False: You can have multiple custom domain names pointing to the same API Gateway API.
- Answer: True
You can have multiple custom domain names pointing to the same API Gateway API, providing flexibility for URLs and possibly serving different audiences.
True or False: Custom domain names in API Gateway can only be associated with one stage.
- Answer: False
Custom domain names in API Gateway can be mapped to different API Gateway stages using base path mapping, which allows different paths to serve different stages.
Multiple-select: What features does API Gateway provide for stages? (Select TWO)
- a. Canary release deployment
- b. Automatic stage backups
- c. Access control using IAM policies
- d. Intrinsic function execution
Answer: a, c
API Gateway provides canary release deployment to enable rolling out changes gradually to a stage. Access control can be managed using IAM policies to specify who can access that particular stage.
In API Gateway, what is the purpose of a stage variable? (Select ONE)
- a. To store API configuration data
- b. To maintain the versioning information for an API
- c. To provide operational parameters that can be changed without redeployment
- d. To enable throttling on specific methods
Answer: c
Stage variables are operational parameters that you can change at any time without redeploying the API. They act like environment variables and can be used in your API setup.
True or False: When setting up a custom domain name in API Gateway, AWS Certificate Manager is often used to provision an SSL certificate.
- Answer: True
AWS Certificate Manager is commonly used to provision, manage, and deploy public and private SSL/TLS certificates for use with AWS services like API Gateway for custom domain names.
Great post on API Gateway stages and custom domains! Really helped me understand how to manage multiple stages in my AWS projects.
Can someone explain how to route traffic to specific API Gateway stages using custom domains?
Lifesaver post! It really clarified how to use API Gateway with custom domains. Thanks!
What are the best practices for managing multiple stages in API Gateway?
This tutorial is fantastic! I’m feeling more prepared for the AWS Certified Developer exam now.
How does custom domain SSL/TLS certificate management work with API Gateway?
Thanks for such a detailed write-up on custom domains!
Good post, but it would be even better if there were examples for integrating with Lambda.