Concepts
API Gateway stages are used to manage the deployment of your APIs. Each stage can be configured with stage variables, which act as environment-specific configuration parameters. For example, a stage variable in the ‘dev’ stage might point to a development database, while the same stage variable in the ‘prod’ stage might point to a production database.
Stage Variables
Stage variables are key-value pairs that can be used in your API configuration. You can use them to pass operational parameters that can be changed independently of the API deployment. This helps reduce the need for hardcoding values that might change between environments.
Example of setting stage variables within the AWS Management Console:
Navigate to your API in API Gateway, select the ‘Stages’ section on the left, choose the stage you want to configure, then in the ‘Stage Variables’ tab, you can set key-value pairs.
Deployment History
Every time an API is deployed to a stage, an immutable snapshot of the API configuration is created and stored in the deployment history. This allows you to roll back to previous deployments if needed. The deployment history is especially valuable for auditing changes and troubleshooting.
To view deployment history:
- Select your API in API Gateway.
- Choose the ‘Stages’ section.
- Select the desired stage.
- Click on the ‘Deployment History’ tab.
Canaries
API Gateway supports canary release deployments, which allow you to roll out changes to a small subset of users before deploying to your entire user base. You can define the percentage of traffic that the canary receives and evaluate the impact of the new version before proceeding with a full deployment.
To set up a canary release:
- Deploy your API to a stage.
- Choose ‘Create’ for the canary setting.
- Specify the percentage of traffic to route to the canary.
Throttling and Caching
Each stage can have separate throttling and caching settings. This allows you to customize performance and limit rates differently for various environments.
Example of setting throttling limits:
- Select the desired stage.
- In the ‘Stage Editor’ panel, set the rate and burst limits under the ‘Default Method Throttling’ section.
Logging and Monitoring
AWS API Gateway stages can be integrated with CloudWatch for logging and monitoring. You can enable access logging to capture information about who accessed your API and how your API was used.
To enable logging in a stage:
- Select the desired stage.
- In the ‘Logs/Tracing’ tab, check the ‘Enable CloudWatch Logs’ box.
- Set the desired log level and choose the IAM role that has the necessary permissions.
Summary
| Feature | Description |
|---|---|
| Stage Variables | Environment parameters for API configuration |
| Deployment History | Immutable snapshots stored for audit and rollback |
| Canary Releases | Incremental rollouts to a subset of users |
| Throttling & Caching | Custom performance settings per stage |
| Logging & Monitoring | Integration with CloudWatch for insights |
Understanding API Gateway stages is pivotal when preparing for the AWS Certified Developer – Associate exam. It’s crucial to grasp how they enable safe deployment practices, environment-specific configurations, performance tuning, and robust operational monitoring. This knowledge is essential for any developer responsible for deploying and managing APIs on AWS.
Answer the Questions in Comment Section
True or False: API Gateway allows you to have multiple stages for different deployment targets for the same API.
- A) True
- B) False
Answer: A) True
Explanation: API Gateway does indeed allow you to have multiple stages for an API, which can be used to manage different deployment targets such as development, testing, and production.
True or False: Throttle settings in API Gateway are set at the method level and cannot be overridden at the stage level.
- A) True
- B) False
Answer: B) False
Explanation: Throttle settings can be set both at the method level and at the stage level in API Gateway. Stage-level throttle settings act as the default for all methods unless overridden at the method level.
Which of the following can be set for a stage in API Gateway? (Select TWO)
- A) Stage variables
- B) Lambda function aliases
- C) CloudWatch Alarms
- D) API Keys
Answer: A) Stage variables, B) Lambda function aliases
Explanation: Stage variables are name-value pairs that can be used to pass operational parameters to a deployment stage. Lambda function aliases can be used in stage variables to point to specific Lambda function versions for different stages.
True or False: It is possible to export an API Gateway stage as a Swagger definition file.
- A) True
- B) False
Answer: A) True
Explanation: API Gateway allows you to export the API definitions for stages as Swagger (now known as OpenAPI) definition files.
What is the purpose of a stage in AWS API Gateway?
- A) To control access to the API
- B) To manage the API lifecycle
- C) To serve as a snapshot of the API
- D) To deploy the API to a specific environment
Answer: D) To deploy the API to a specific environment
Explanation: Stages in AWS API Gateway are used to deploy the API to specific environments like development, testing, or production.
True or False: API Gateway does not allow logging and monitoring settings to be defined per stage.
- A) True
- B) False
Answer: B) False
Explanation: API Gateway allows for detailed logging and monitoring settings to be defined for each stage using Amazon CloudWatch.
Which feature of API Gateway stages enables direct calls to different versions of Lambda functions or other HTTP endpoints?
- A) Lambda integration
- B) Stage variables
- C) Usage plans
- D) Method snapshots
Answer: B) Stage variables
Explanation: Stage variables in API Gateway enable you to make direct calls to different versions of Lambda functions or other HTTP endpoints based on which stage the API request is being served from.
When defining a canary release, what percentage of traffic can be specified to go to the canary version of a stage in API Gateway?
- A) Between 1% to 50%
- B) Between 0% to 99%
- C) Exactly 50%
- D) Between 5% to 5%
Answer: B) Between 0% to 99%
Explanation: When defining a canary release in API Gateway, you can specify what percentage of traffic will be directed to the canary version, and it can range from 0% up to 99%.
True or False: You can use a custom domain name to invoke different stages of an API Gateway API.
- A) True
- B) False
Answer: A) True
Explanation: Custom domain names can be set up in API Gateway, allowing different base paths to map to different stages of an API, thus enabling the invocation of different API stages.
Is it possible to roll back an API Gateway stage to a previous deployment?
- A) Yes, always
- B) No, it’s not possible
- C) Yes, but only if the stage was associated with a documented deployment
- D) Yes, but only within 24 hours of the deployment
Answer: C) Yes, but only if the stage was associated with a documented deployment
Explanation: It is possible to roll back an API Gateway stage to a previous deployment if that deployment was documented and has a unique identifier.
True or False: Stage variables in API Gateway are versioned just like the API itself.
- A) True
- B) False
Answer: B) False
Explanation: Stage variables are not versioned in the same way that APIs are. They are linked to the stage and can be changed independently of the API’s deployment history.
Which AWS service can be directly integrated with API Gateway stages to manage user permissions and access control?
- A) AWS Lambda
- B) AWS KMS
- C) Amazon Cognito
- D) AWS IAM
Answer: D) AWS IAM
Explanation: AWS IAM (Identity and Access Management) can be directly integrated with API Gateway to manage user permissions and access control for API stages.
Great post about API Gateway stages! Really helped me understand the topic for my DVA-C02 exam.
Can someone explain what logical and deployment stages are in API Gateway?
Thanks for this post! Helped me clarify some doubts!
What’s the significance of stage variables in API Gateway?
Appreciate the detailed explanation on stages. Helped a lot for my certification prep.
Understood logical stages but still unclear about deployment stages. Can someone elaborate?
Found a minor typo in the post but otherwise very helpful.
Thanks for clearing up the confusion about deployment and logical stages.