http-dynamodb-crud-api

CRUD HTTP API Gateway for DynamoDB CDK Python project!

This is a CRUD API project using Lambda and DynamoDB for CDK development with Python. In this project, you create a serverless API that creates, reads, updates, and deletes items from a DynamoDB table.

The cdk.json file tells the CDK Toolkit how to execute your app.

This project is set up like a standard Python project. The initialization process also creates a virtualenv within this project, stored under the .venv directory. To create the virtualenv it assumes that there is a python3 (or python for Windows) executable in your path with access to the venv package. If for any reason the automatic creation of the virtualenv fails, you can create the virtualenv manually.

To manually create a virtualenv on MacOS and Linux:

$ python3 -m venv .venv

After the init process completes and the virtualenv is created, you can use the following step to activate your virtualenv.

$ source .venv/bin/activate

If you are a Windows platform, you would activate the virtualenv like this:

% .venv\Scripts\activate.bat

Once the virtualenv is activated, you can install the required dependencies.

(.venv) $ pip install -r requirements.txt

Before synthesizing the CloudFormation, you should set approperly the cdk context configuration file, cdk.context.json.

For example:

{
  "vpc_name": "default",
  "dynamodb": {
    "table_name": "http-crud-tutorial-items",
    "partition_key": "id",
    "time_to_live_attribute": "ttl"
  }
}

At this point you can now synthesize the CloudFormation template for this code.

(.venv) $ export CDK_DEFAULT_ACCOUNT=$(aws sts get-caller-identity --query Account --output text)
(.venv) $ export CDK_DEFAULT_REGION=$(aws configure get region)
(.venv) $ cdk synth --all

Use cdk deploy command to create the stack shown above,

(.venv) $ cdk deploy --all

To add additional dependencies, for example other CDK libraries, just add them to your setup.py file and rerun the pip install -r requirements.txt command.

Test

To create or update an item

Use the following command to create or update an item. The command includes a request body with the item's ID, price, and name.

curl -X "PUT" -H "Content-Type: application/json" -d "{\"id\": \"123\", \"price\": 12345, \"name\": \"myitem\"}" https://abcdef123.execute-api.us-east-1.amazonaws.com/items

HTTP Request Event Example for Lambda function:

{
  version: '2.0',
  routeKey: 'PUT /items',
  rawPath: '/items',
  rawQueryString: '',
  headers: {
    accept: '*/*',
    'content-length': '47',
    'content-type': 'application/json',
    host: 'abcdef123.execute-api.us-east-1.amazonaws.com',
    'user-agent': 'curl/7.87.0',
    'x-amzn-trace-id': 'Root=1-64562dc6-7752b044606e259624b293e4',
    'x-forwarded-for': '172.31.171.253',
    'x-forwarded-port': '443',
    'x-forwarded-proto': 'https'
  },
  requestContext: {
    accountId: '123456789012',
    apiId: 'abcdef123',
    domainName: 'abcdef123.execute-api.us-east-1.amazonaws.com',
    domainPrefix: 'abcdef123',
    http: {
      method: 'PUT',
      path: '/items',
      protocol: 'HTTP/1.1',
      sourceIp: '172.31.171.253',
      userAgent: 'curl/7.87.0'
    },
    requestId: 'EfwW_jHaoAMEJXw=',
    routeKey: 'PUT /items',
    stage: '$default',
    time: '06/May/2023:10:36:54 +0000',
    timeEpoch: 1683369414051
  },
  body: '{"id": "123", "price": 12345, "name": "myitem"}',
  isBase64Encoded: false
}

To get all items

Use the following command to list all items.

curl https://abcdef123.execute-api.us-east-1.amazonaws.com/items

HTTP Request Event Example for Lambda function:

{
  version: '2.0',
  routeKey: 'GET /items',
  rawPath: '/items',
  rawQueryString: '',
  headers: {
    accept: '*/*',
    'content-length': '0',
    host: 'abcdef123.execute-api.us-east-1.amazonaws.com',
    'user-agent': 'curl/7.87.0',
    'x-amzn-trace-id': 'Root=1-645625ef-1800537b7453cfdf4f7fe05f',
    'x-forwarded-for': '172.31.171.253',
    'x-forwarded-port': '443',
    'x-forwarded-proto': 'https'
  },
  requestContext: {
    accountId: '123456789012',
    apiId: 'abcdef123',
    domainName: 'abcdef123.execute-api.us-east-1.amazonaws.com',
    domainPrefix: 'abcdef123',
    http: {
      method: 'GET',
      path: '/items',
      protocol: 'HTTP/1.1',
      sourceIp: '172.31.171.253',
      userAgent: 'curl/7.87.0'
    },
    requestId: 'EfrdZjP6IAMEJgw=',
    routeKey: 'GET /items',
    stage: '$default',
    time: '06/May/2023:10:03:27 +0000',
    timeEpoch: 1683367407068
  },
  isBase64Encoded: false
}

To get an item

Use the following command to get an item by its ID.

curl https://abcdef123.execute-api.us-east-1.amazonaws.com/items/123

HTTP Request Event Example for Lambda function:

{
  version: '2.0',
  routeKey: 'GET /items/{id}',
  rawPath: '/items/123',
  rawQueryString: '',
  headers: {
    accept: '*/*',
    'content-length': '0',
    host: 'abcdef123.execute-api.us-east-1.amazonaws.com',
    'user-agent': 'curl/7.87.0',
    'x-amzn-trace-id': 'Root=1-64562ee6-0fcaba570c17f78b7e3a9006',
    'x-forwarded-for': '172.31.171.253',
    'x-forwarded-port': '443',
    'x-forwarded-proto': 'https'
  },
  requestContext: {
    accountId: '123456789012',
    apiId: 'abcdef123',
    domainName: 'abcdef123.execute-api.us-east-1.amazonaws.com',
    domainPrefix: 'abcdef123',
    http: {
      method: 'GET',
      path: '/items/123',
      protocol: 'HTTP/1.1',
      sourceIp: '172.31.171.253',
      userAgent: 'curl/7.87.0'
    },
    requestId: 'EfxEEgdMIAMES7w=',
    routeKey: 'GET /items/{id}',
    stage: '$default',
    time: '06/May/2023:10:41:42 +0000',
    timeEpoch: 1683369702592
  },
  pathParameters: { id: '123' },
  isBase64Encoded: false
}

To delete an item

Use the following command to delete an item.

curl -X "DELETE" https://abcdef123.execute-api.us-east-1.amazonaws.com/items/123

HTTP Request Event Example for Lambda function:

{
  version: '2.0',
  routeKey: 'DELETE /items/{id}',
  rawPath: '/items/123',
  rawQueryString: '',
  headers: {
    accept: '*/*',
    'content-length': '0',
    host: 'abcdef123.execute-api.us-east-1.amazonaws.com',
    'user-agent': 'curl/7.87.0',
    'x-amzn-trace-id': 'Root=1-64562f8d-43d9def50321e9dd0f470f59',
    'x-forwarded-for': '172.31.171.253',
    'x-forwarded-port': '443',
    'x-forwarded-proto': 'https'
  },
  requestContext: {
    accountId: '123456789012',
    apiId: 'abcdef123',
    domainName: 'abcdef123.execute-api.us-east-1.amazonaws.com',
    domainPrefix: 'abcdef123',
    http: {
      method: 'DELETE',
      path: '/items/123',
      protocol: 'HTTP/1.1',
      sourceIp: '172.31.171.253',
      userAgent: 'curl/7.87.0'
    },
    requestId: 'EfxeOg2YIAMEJUw=',
    routeKey: 'DELETE /items/{id}',
    stage: '$default',
    time: '06/May/2023:10:44:29 +0000',
    timeEpoch: 1683369869936
  },
  pathParameters: { id: '123' },
  isBase64Encoded: false
}

Clean Up

Delete the CloudFormation stack by running the below command.

(.venv) $ cdk destroy --force --all

Useful commands

• cdk ls list all stacks in the app
• cdk synth emits the synthesized CloudFormation template
• cdk deploy deploy this stack to your default AWS account/region
• cdk diff compare deployed stack with current state
• cdk docs open CDK documentation

Enjoy!

References

• Amazon API Gateway - Tutorial: Build a CRUD API with Lambda and DynamoDB
• Simple HTTP CRUD API for DynamoDB CDK Typescript Project in AWS CDK v1
• Http API Example in AWS CDK Typescript (API Gateway V2)
• Amazon API Gateway - Working with AWS Lambda proxy integrations for HTTP APIs
• Amazon API Gateway - Working with HTTP APIs