Blank function (Python)

The project source includes function code and supporting resources:

function - A Python function.
template.yml - An AWS CloudFormation template that creates an application.
1-create-bucket.sh, 2-build-layer.sh, etc. - Shell scripts that use the AWS CLI to deploy and manage the application.

Use the following instructions to deploy the sample application.

Requirements

Python 3.7
The Bash shell. For Linux and macOS, this is included by default. In Windows 10, you can install the Windows Subsystem for Linux to get a Windows-integrated version of Ubuntu and Bash.
The AWS CLI v1.17 or newer.

If you use the AWS CLI v2, add the following to your configuration file (~/.aws/config):

cli_binary_format=raw-in-base64-out

This setting enables the AWS CLI v2 to load JSON events from a file, matching the v1 behavior.

Setup

Download or clone this repository.

$ git clone https://github.com/awsdocs/aws-lambda-developer-guide.git
$ cd aws-lambda-developer-guide/sample-apps/blank-python

To create a new bucket for deployment artifacts, run 1-create-bucket.sh.

blank-python$ ./1-create-bucket.sh
make_bucket: lambda-artifacts-a5e491dbb5b22e0d

To build a Lambda layer that contains the function's runtime dependencies, run 2-build-layer.sh. Packaging dependencies in a layer reduces the size of the deployment package that you upload when you modify your code.

blank-python$ ./2-build-layer.sh

Deploy

To deploy the application, run 3-deploy.sh.

blank-python$ ./3-deploy.sh
Uploading to e678bc216e6a0d510d661ca9ae2fd941  9519118 / 9519118.0  (100.00%)
Successfully packaged artifacts and wrote output template to file out.yml.
Waiting for changeset to be created..
Waiting for stack create/update to complete
Successfully created/updated stack - blank-python

This script uses AWS CloudFormation to deploy the Lambda functions and an IAM role. If the AWS CloudFormation stack that contains the resources already exists, the script updates it with any changes to the template or function code.

Test

To invoke the function, run 4-invoke.sh.

blank-python$ ./4-invoke.sh
{
    "StatusCode": 200,
    "ExecutedVersion": "$LATEST"
}
{"TotalCodeSize": 410713698, "FunctionCount": 45}

Let the script invoke the function a few times and then press CRTL+C to exit.

The application uses AWS X-Ray to trace requests. Open the X-Ray console to view the service map. The following service map shows the function calling Amazon S3.

Choose a node in the main function graph. Then choose View traces to see a list of traces. Choose any trace to view a timeline that breaks down the work done by the function.

Cleanup

To delete the application, run 5-cleanup.sh.