Why API deployment and stages in AWS? - Purpose & Use Cases

The Big Idea

What if you could update your API without breaking anything or confusing your users?

The Scenario

Imagine you have built an API and want to share it with your team and users. You try to update the API by manually copying files and changing settings on each server. You have no clear way to separate testing from live use. It's like trying to update a recipe by rewriting it on sticky notes and handing them out one by one.

The Problem

Manually updating APIs is slow and confusing. Mistakes happen easily, like forgetting to update one server or mixing test changes with live ones. It's hard to know which version is running, causing bugs and unhappy users. This manual work wastes time and causes stress.

The Solution

API deployment and stages let you organize your API versions clearly. You can create separate stages like 'test', 'dev', and 'production'. Each stage holds a stable version of your API. Deploying updates becomes a simple, repeatable process. You can test safely before going live, avoiding mistakes and confusion.

Before vs After

✗ Before

Copy files to server A
Copy files to server B
Change config on server A
Change config on server B

✓ After

Deploy API to 'dev' stage
Test API in 'dev'
Promote API to 'production' stage

What It Enables

You can safely update and manage your API versions, giving users a reliable and smooth experience without downtime or errors.

Real Life Example

A company launches a new feature in their app. They deploy the API update first to a 'test' stage to check for bugs. After confirming it works well, they promote the API to 'production' so all users get the new feature without disruption.

Key Takeaways

Manual API updates are slow and error-prone.

Deployment stages organize API versions for safe testing and release.

Using stages improves reliability and user experience.

Practice

1. What is the main purpose of an API stage in AWS API Gateway?

easy

A. To monitor network traffic outside AWS

B. To store API keys for users

C. To create backend Lambda functions

D. To manage different versions or environments of the API

Solution

1. Step 1: Understand API stages concept

   API stages in AWS API Gateway represent different versions or environments like development, testing, or production.

2. Step 2: Identify the role of stages

   Stages allow you to deploy and manage separate API versions independently.

3. Final Answer:

   To manage different versions or environments of the API -> Option D

4. Quick Check:

   API stages = version/environment management [OK]

Hint: Stages separate API versions or environments [OK]

Common Mistakes:

• Confusing stages with API keys
• Thinking stages create backend functions
• Assuming stages monitor external traffic

2. Which AWS CLI command is used to create a new deployment for an API Gateway REST API?

easy

A. aws apigateway create-deployment

B. aws apigateway create-stage

C. aws apigateway deploy-api

D. aws apigateway new-deployment

Solution

1. Step 1: Identify the correct AWS CLI command for deployment

   The command to create a deployment in API Gateway is create-deployment.

2. Step 2: Differentiate from other commands

   create-stage creates a stage, not a deployment. Other options are invalid commands.

3. Final Answer:

   aws apigateway create-deployment -> Option A

4. Quick Check:

   Deployment command = create-deployment [OK]

Hint: Deploy with 'create-deployment' command [OK]

Common Mistakes:

• Using create-stage instead of create-deployment
• Assuming deploy-api is a valid command
• Confusing deployment with stage creation

3. Given the following AWS CLI command:
aws apigateway create-stage --rest-api-id abc123 --stage-name prod --deployment-id dep456
What does this command do?

medium

A. Creates a new deployment named 'prod' for API 'abc123'

B. Creates a new stage 'prod' linked to deployment 'dep456' for API 'abc123'

C. Deletes the stage 'prod' from API 'abc123'

D. Updates the deployment 'dep456' with stage 'prod'

Solution

1. Step 1: Analyze the command parameters

   The command is create-stage with parameters for API ID, stage name, and deployment ID.

2. Step 2: Understand the effect of create-stage

   This creates a new stage named 'prod' that points to the deployment 'dep456' for the API 'abc123'.

3. Final Answer:

   Creates a new stage 'prod' linked to deployment 'dep456' for API 'abc123' -> Option B

4. Quick Check:

   create-stage + deployment-id = new stage linked to deployment [OK]

Hint: create-stage links stage to deployment by deployment-id [OK]

Common Mistakes:

• Confusing stage creation with deployment creation
• Thinking it deletes or updates instead
• Mixing up stage name and deployment ID

4. You ran this command to deploy your API stage:
aws apigateway create-stage --rest-api-id abc123 --stage-name test --deployment-id dep789
But you get an error saying the deployment ID does not exist. What is the likely cause?

medium

A. The deployment ID 'dep789' was not created before creating the stage

B. The stage name 'test' is invalid

C. The rest-api-id 'abc123' is incorrect format

D. You must create the stage before creating the deployment

Solution

1. Step 1: Understand the dependency between deployment and stage

   A stage must point to an existing deployment. If deployment ID does not exist, stage creation fails.

2. Step 2: Identify the error cause

   The error indicates deployment 'dep789' was not created or is invalid before stage creation.

3. Final Answer:

   The deployment ID 'dep789' was not created before creating the stage -> Option A

4. Quick Check:

   Stage needs existing deployment ID [OK]

Hint: Create deployment before stage with deployment ID [OK]

Common Mistakes:

• Assuming stage name format causes error
• Thinking API ID format is the issue
• Believing stage must be created before deployment

5. You want to deploy a new version of your API to a 'prod' stage without affecting the current live API. Which sequence of AWS CLI commands should you use?

hard

A. aws apigateway create-deployment -> aws apigateway create-stage with 'prod'

B. aws apigateway create-stage with 'prod' -> aws apigateway create-deployment

C. aws apigateway create-deployment -> aws apigateway update-stage with 'prod'

D. aws apigateway update-stage with 'prod' -> aws apigateway create-deployment

Solution

1. Step 1: Deploy new API version

   First, create a new deployment to capture the latest API changes.

2. Step 2: Update existing 'prod' stage to point to new deployment

   Use update-stage to switch the 'prod' stage to the new deployment without creating a new stage.

3. Final Answer:

   aws apigateway create-deployment -> aws apigateway update-stage with 'prod' -> Option C

4. Quick Check:

   Deploy then update stage to switch versions [OK]

Hint: Create deployment then update existing stage [OK]

Common Mistakes:

• Creating a new stage instead of updating existing
• Updating stage before deployment exists
• Assuming create-stage can update existing stage