cloudwatch-log-retention

Lambda function which sets the retention period on cloudwatch log groups when the log group is create or if the retention period is modified.

Building the 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

# Remember to build your handler executable for Linux!
GOOS=linux GOARCH=amd64 go build -o main main.go
zip main.zip main

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

go.exe get -u github.com/aws/aws-lambda-go/cmd/build-lambda-zip

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:

set GOOS=linux
set GOARCH=amd64
set CGO_ENABLED=0
go build -o main main.go
%USERPROFILE%\Go\bin\build-lambda-zip.exe -o main.zip main

in Powershell:

$env:GOOS = "linux"
$env:GOARCH = "amd64"
$env:CGO_ENABLED = "0"
go build -o main main.go
~\Go\Bin\build-lambda-zip.exe -o main.zip main

Terraform Deployment

The Terraform deployment is dependent on Terraform Master project for certain variables such as the KMS Key to use. This Terraform project uses workspaces to deploy in to different environments therefore the appropriate workspace should be selected first.

The first thing to do is move the Lambda zip file to the deployment folder. Then run the following commands to deploy the Lambda function.

terraform init "-backend-config=backend.tfvars"
terraform workspace select development
terraform plan "-var-file=master.tfvars"
terraform apply "-var-file=master.tfvars"