Get As a Function, Eh!

An AWS Lambda that will do HTTP Get requests for you.

Is this any good?

Yes.

What?

Send a JSON payload to the lambda with headers and uri and the code does request for the uri using your headers. You get back a JSON with the AWS Request ID of the lambda invocation, the HTTP status and the response headers. The response body is base64 encoded.

Example

Request

{
	"uri": "https://example.org",
	"headers": {
		"x-foo": "bar"
	}
}

Response

{
	"req_id": "dd50c345-8373-4145-8883-1717f2da7f75",
	"status": 200,
	"headers": {
		"accept-ranges": "bytes",
		"vary": "Accept-Encoding"
        ...
	},
	"body": "PCF..."
}

How?

The Lambda Rust Runtime has detailed information on how to buld and deploy rust functions. But the quick and dirty is:

1. Build and package the binary using the rustserverless/lambda-rust docker image:

docker run --rm -u $(id -u):$(id -g) \
  -e BIN=gafe \
  -v ${PWD}:/code \
  -v ${HOME}/.cargo/registry:/cargo/registry \
  -v ${HOME}/.cargo/git:/cargo/git \
  rustserverless/lambda-rust:latest

You can use the image rustserverless/lambda-rust:latest-arm64 if your CPU is a 64-bit ARM.

2. Deploy function using the AWS CLI:

 aws lambda create-function --function-name rustTest \
  --handler bootstrap \
  --zip-file fileb://./target/lambda/gafe/bootstrap.zip \
  --runtime provided.al2
  --role arn:aws:iam::XXXXXXXXXXXXX:role/your_lambda_execution_role \
  --environment Variables={LOG_LEVEL=info}

3. Test it out

$ aws lambda invoke
  --cli-binary-format raw-in-base64-out \
  --function-name rustTest \
  --payload '{"uri": "https://example.org", "headers": {"x-foo":"bar"}}' \
  output.json
$ cat output.json # Prints the full non-formated version of the example response from above

NOTES:

Payload limit (request and response):

6 MB (synchronous) 256 KB (asynchronous)