outofcoffee / lambda-http-gateway

Simple HTTP Gateway for AWS Lambda functions

Lambda HTTP Gateway

Simple HTTP gateway for AWS Lambda. Acts as a lightweight API gateway for AWS Lambda functions.

Run

You can download the binary for your platform from the releases page, or use the Docker image.

Important: Ensure the relevant AWS credentials are configured before run. The gateway uses the standard AWS mechanisms to authenticate/authorise with the AWS Lambda API, so the usual approaches of profiles/credentials apply.

Binary

./lambdahttpgw

Docker

docker run -it -p 8090:8090 outofcoffee/lambdahttpgw

Note: the home directory for the gateway user that runs the binary is /opt/gateway

Call Lambda function

Call the Lambda function via the gateway:

curl http://localhost:8090/MyLambdaName/some/path
...
<Lambda HTTP response>

Note the prefix of the Lambda function name (MyLambdaName above), before the path. The function receives the portion of the path without the function name, i.e. /some/path in this example.

The Lambda function receives events in the standard AWS API Gateway JSON format, and is expected to respond in kind.

Configuration

Environment variables:

Variable	Meaning	Default	Example
AWS_REGION	AWS region in which to connect to Lambda functions.	eu-west-1	us-east-1
LOG_LEVEL	Log level (trace, debug, info, warn, error).	debug	warn
PORT	Port on which to listen.	8090	8080
REQUEST_ID_HEADER	Name of request header to use as request ID for logging. If absent, a UUID will be used.	Empty	x-correlation-id
STATS_RECORDER	Whether to record number of hits for each function.	false	true
STATS_REPORT_INTERVAL	The frequency with which stats should be reported, if enabled.	5s	2m
STATS_REPORT_URL	URL to which stats should be reported. If not empty, hits are recorded for each function name.	Empty	https://example.com

Build

Prerequisites:

• Go 1.17+

Steps:

go build

Docker image

Image on Docker Hub:

outofcoffee/lambdahttpgw

Stats recording and reporting

The Gateway can optionally record the number of hits per function and report it to an external hit counter server.

This behaviour is disabled by default.

See Stats recording and reporting for details.