Creating AWS Lambda Functions From Octopus Deployments

AWS Lambda is one of the AWS Compute Services, alongside with Amazon EC2 or Amazon EC2 Container Service. In a nutshell, AWS Lambda is the serverless offering from AWS, allowing you to “run code without provisioning or managing servers.”

In the DevOps spirit, and using Octopus as a continuous deployment tool, I couldn’t find a step template to create an AWS Lambda function. If doesn’t exist, create it, and give it away!

Background

AWS Lambda supports a broad range of technologies, such as Java, Python, and Node.js. The new kid on the block was .NET Core, announced on Dec. 1, 2016. It was a good announcement for Microsoft tech shops, adding another tool in the toolbelt.

The tools used for this demo were:

• Visual Studio 2015 Community Edition.
• AWS Toolkit for Visual Studio.
• AWS Tools for Windows Powershell.
• Octopus Deploy Community Edition.

Visual Studio and AWS Lambda Function Project

Using one of the Visual Studio AWS Lambda templates for the demo, the project was created and committed here. In a nutshell, the AWS Lambda function receives an Amazon S3 event and returns the S3 object Content Type. Simple and straightforward.

Continuous Integration Server

You can use your preferred CI server. It will need to handle the following:

1. Publish the AWS Lambda .NET project

   dotnet publish AWSLambdaDemo -c Release

2. Zip the published AWS Lambda .NET project
3. Create the NuGet package for Octopus 

   Octo.exe pack --id AWSLambdaDemo --version 1.0.0.0

4. Upload the AWS Lambda NuGet package to Octopus Server 

   NuGet.exe push AWSLambdaDemo.nupkg -ApiKey myApiKey -Source https://myOctopusServer

These instructions are generic and, depending on your CI server technology, can be done in different ways. You can take them as generic steps and just adapt them to your needs.

Creating the AWS Lambda Function Step Template

The step template is simple and straightforward. The PowerShell script:

1. Checks if the AWS Tools for Windows PowerShell is installed.
2. Gets all the required parameters, such as the access keys, region, function name, among others.
3. Validates the parameters.
4. Executes the operation.
5. Provides feedback to the user.

The step template has a prerequisite — it depends on the AWS Tools for Windows PowerShell. You need to download and install it on the machines where the step will run.

Octopus Project

To create the AWS Lambda function, we need to use a pivot machine. At the moment, it is not possible to publish it directly to AWS.

We will use some out-of-the-box Octopus features to deploy the AWSLambdaDemo package to the pivot machine, and the new step template will publish the function to AWS.

The demo octopus project will look like this:

The first step just deploys the uploaded NuGet AWSLambdaDemo package to a custom location in the pivot machine (with the role "AWS Lambda Demo").

The second step creates the AWS Lambda from the deployed NuGet AWSLambdaDemo package from the custom location.

After creating a release (potentially triggered by the CI server), the Octopus server can deploy it.

And voilá! A new AWS Lambda function is deployed!

Final Thoughts

The step template is under the Octopus Library OSS. You can fork and add new features to it, or open an issue in my fork. All suggestions are welcome.