This template demonstrates how to make a simple REST API with Python running on AWS Lambda and API Gateway using the traditional Serverless Framework.

Serverless Framework Python REST API on AWS

This template demonstrates how to make a simple REST API with Python running on AWS Lambda and API Gateway using the traditional Serverless Framework.

This template does not include any kind of persistence (database). For a more advanced examples check out the examples repo which includes DynamoDB, Mongo, Fauna and other examples.

Usage

Deployment

This example is made to work with the Serverless Framework dashboard which includes advanced features like CI/CD, monitoring, metrics, etc.

$ serverless login
$ serverless deploy

To deploy without the dashboard you will need to remove org and app fields from the serverless.yml, and you won’t have to run sls login before deploying.

After running deploy, you should see output similar to:

Serverless: Packaging service...
Serverless: Excluding development dependencies...
Serverless: Creating Stack...
Serverless: Checking Stack create progress...
........
Serverless: Stack create finished...
Serverless: Uploading CloudFormation file to S3...
Serverless: Uploading artifacts...
Serverless: Uploading service aws-python-rest-api.zip file to S3 (711.23 KB)...
Serverless: Validating template...
Serverless: Updating Stack...
Serverless: Checking Stack update progress...
.................................
Serverless: Stack update finished...
Service Information
service: aws-python-rest-api
stage: dev
region: us-east-1
stack: aws-python-rest-api-dev
resources: 12
api keys:
  None
endpoints:
  ANY - https://xxxxxxx.execute-api.us-east-1.amazonaws.com/dev/
functions:
  api: aws-python-rest-api-dev-hello
layers:
  None

Note: In current form, after deployment, your API is public and can be invoked by anyone. For production deployments, you might want to configure an authorizer. For details on how to do that, refer to http event docs.

Invocation

After successful deployment, you can call the created application via HTTP:

curl https://xxxxxxx.execute-api.us-east-1.amazonaws.com/dev/

Which should result in response similar to the following (removed input content for brevity):

{
  "message": "Go Serverless v2.0! Your function executed successfully!",
  "input": {
    ...
  }
}

Local development

You can invoke your function locally by using the following command:

serverless invoke local --function hello

Which should result in response similar to the following:

{
  "statusCode": 200,
  "body": "{\n  \"message\": \"Go Serverless v2.0! Your function executed successfully!\",\n  \"input\": \"\"\n}"
}

Alternatively, it is also possible to emulate API Gateway and Lambda locally by using serverless-offline plugin. In order to do that, execute the following command:

serverless plugin install -n serverless-offline

It will add the serverless-offline plugin to devDependencies in package.json file as well as will add it to plugins in serverless.yml.

After installation, you can start local emulation with:

serverless offline

To learn more about the capabilities of serverless-offline, please refer to its GitHub repository.

Bundling dependencies

In case you would like to include 3rd party dependencies, you will need to use a plugin called serverless-python-requirements. You can set it up by running the following command:

serverless plugin install -n serverless-python-requirements

Running the above will automatically add serverless-python-requirements to plugins section in your serverless.yml file and add it as a devDependency to package.json file. The package.json file will be automatically created if it doesn't exist beforehand. Now you will be able to add your dependencies to requirements.txt file (Pipfile and pyproject.toml is also supported but requires additional configuration) and they will be automatically injected to Lambda package during build process. For more details about the plugin's configuration, please refer to official documentation.