sam-golang-multi-lambda

sam-golang-multi-lambda

This is a sample project that shows how to build and deploy a AWS Lambda function using the SAM CLI that contains multiple functions defined in a single Golang project.

The aim is to illustrate some of the more advanced features of the SAM CLI like building and deploying multiple Go based lambda functions from a single module.

This is a follow up from my blog post https://www.wolfe.id.au/2023/08/09/rip-aws-go-lambda-runtime/ where I discussed how AWS is deprecating the Go Lambda Runtime in favor of the generic provided.al2 runtime.

Outline

Some things to note about this project:

1. The project is a single Go module that contains multiple Lambda function binaries, shared code can be stored in /pkg or /internal and imported by any of the functions.
2. The Makefile contains custom build flags to ensure a version is provided to each, as well as ldflags and the flag to remove the RPC endpoint from the binaries.
3. There is a template.yaml that defines the AWS Serverless Application Model (SAM) resources for each function individually.

++Note:++ I have used the AWS::Serverless::Function resource Metadata to specify the function BuildMethod as go1.x to ensure each is built and packaged separately. This is mentioned in the migration blog post titled Migrating AWS Lambda functions from the Go1.x runtime to the custom runtime on Amazon Linux 2.

The layout of the project is as follows:

.
├── Makefile
├── README.md
├── cmd
│   ├── api-lambda
│   │   ├── main.go
│   │   └── main_test.go
│   └── scheduled-lambda
│       ├── main.go
│       └── main_test.go
├── events
│   └── event.json
├── go.mod
├── go.sum
├── samconfig.toml
└── template.yaml

Requirements

• AWS CLI already configured with Administrator permission
• Golang
• SAM CLI - Install the SAM CLI

Installing dependencies & building the target

In this example we use the built-in sam build to automatically download all the dependencies and package our build target.
Read more about SAM Build here

The sam build command is wrapped inside of the Makefile. To execute this simply run

make

License

This project is released under Apache 2.0 license and is copyright Mark Wolfe.