# AWS Lambda for Go 

[![tests][1]][2]
[![build-lambda-zip][3]][4]
[![Go Reference][5]][6]
[![GoCard][7]][8]
[![codecov][9]][10]

[1]: https://github.com/aws/aws-lambda-go/workflows/tests/badge.svg
[2]: https://github.com/aws/aws-lambda-go/actions?query=workflow%3Atests
[3]: https://github.com/aws/aws-lambda-go/workflows/go%20get%20build-lambda-zip/badge.svg
[4]: https://github.com/aws/aws-lambda-go/actions?query=workflow%3A%22go+get+build-lambda-zip%22
[5]: https://pkg.go.dev/badge/github.com/aws/aws-lambda-go.svg
[6]: https://pkg.go.dev/github.com/aws/aws-lambda-go
[7]: https://goreportcard.com/badge/github.com/aws/aws-lambda-go
[8]: https://goreportcard.com/report/github.com/aws/aws-lambda-go
[9]: https://codecov.io/gh/aws/aws-lambda-go/branch/master/graph/badge.svg
[10]: https://codecov.io/gh/aws/aws-lambda-go

Libraries, samples, and tools to help Go developers develop AWS Lambda functions.

To learn more about writing AWS Lambda functions in Go, go to [the official documentation](https://docs.aws.amazon.com/lambda/latest/dg/go-programming-model.html)

# Getting Started

``` Go
// main.go
package main

import (
	"github.com/aws/aws-lambda-go/lambda"
)

func hello() (string, error) {
	return "Hello λ!", nil
}

func main() {
	// Make the handler available for Remote Procedure Call by AWS Lambda
	lambda.Start(hello)
}
```

# Building your function

Preparing a binary to deploy to AWS Lambda requires that it is compiled for Linux and placed into a .zip file.

## For developers on Linux and macOS
``` shell
# Remember to build your handler executable for Linux!
# When using the `provided.al2` runtime, the handler executable should be named `bootstrap`
GOOS=linux GOARCH=amd64 go build -o bootstrap main.go
zip lambda-handler.zip bootstrap
```

## For developers on Windows

Windows developers may have trouble producing a zip file that marks the binary as executable on Linux. To create a .zip that will work on AWS Lambda, the `build-lambda-zip` tool may be helpful.

Get the tool
``` shell
go.exe install github.com/aws/aws-lambda-go/cmd/build-lambda-zip@latest
```

Use the tool from your `GOPATH`. If you have a default installation of Go, the tool will be in `%USERPROFILE%\Go\bin`. 

in cmd.exe:
``` bat
set GOOS=linux
set GOARCH=amd64
set CGO_ENABLED=0
go build -o bootstrap main.go
%USERPROFILE%\Go\bin\build-lambda-zip.exe -o lambda-handler.zip bootstrap
```

in Powershell:
``` posh
$env:GOOS = "linux"
$env:GOARCH = "amd64"
$env:CGO_ENABLED = "0"
go build -o bootstrap main.go
~\Go\Bin\build-lambda-zip.exe -o lambda-handler.zip bootstrap
```
# Deploying your functions

To deploy your function, refer to the official documentation for [deploying using the AWS CLI, AWS Cloudformation, and AWS SAM](https://docs.aws.amazon.com/lambda/latest/dg/deploying-lambda-apps.html).

# Event Integrations

The [event models](https://github.com/aws/aws-lambda-go/tree/master/events) can be used to model AWS event sources. The official documentation has [detailed walkthroughs](https://docs.aws.amazon.com/lambda/latest/dg/use-cases.html).