lambda-echoip

README

Lambda function to answer the question: What's my IP?

When invoked via an AWS application level loadbalancer (ELB) the function will return the IP of the requesting client.

Prerequisites

• aws cli installed and configured with credentials and default region
• GNU Make
• Go >= 1.15.x

Install

1. Create function execution role and note down the Arn of the role (e.g. arn:aws:iam::123456789012:role/lambda-echoip)

aws iam create-role --role-name lambda-echoip --assume-role-policy-document file://trust-policy.json`

1. Build the deployment package function.zip:

make build

1. Create function and note down the Function ARN (e.g. arn:aws:lambda:eu-west-1:123456789012:function:lambda-echoip):

aws lambda create-function --function-name lambda-echoip --runtime go1 --handler main --zip-file fileb://function.zip --role arn:aws:iam::123456789012:role/lambda-echoip`

1. Create ELB target group for the function, and note down the TargetGroupArn (e.g. arn:aws:elasticloadbalancing:eu-west-1:123456789012:targetgroup/lambda-echoip/7e8a3b1bb81b9338")

aws elbv2 create-target-group --name lambda-echoip --target-type lambda

1. Grant ELB invocation rights on function:

aws lambda add-permission \
    --function-name lambda-echoip \
    --statement-id load-balancer \
    --principal elasticloadbalancing.amazonaws.com \
    --action lambda:InvokeFunction \
    --source-arn arn:aws:elasticloadbalancing:eu-west-1:123456789012:targetgroup/lambda-echoip/7e8a3b1bb81b9338

1. Register function as ELB target:

aws elbv2 register-targets \
    --target-group-arn arn:aws:elasticloadbalancing:eu-west-1:123456789012:targetgroup/lambda-echoip/7e8a3b1bb81b9338 \
    --targets Id=arn:aws:lambda:eu-west-1:123456789012:function:lambda-echoip

1. Test function:

curl echoip-123456789.eu-west-1.elb.amazonaws.com

Development

• make help shows Makefile targets
• make test runs the tests
• make deploy will update an existing deployment with the new code