regproxy

An http reverse proxy with a dynamic list of upstreams.

Requests are forwarded to all upstreams in parallel and all are expected to be successful. Only one response is returned to the client.

Use cases:

It can be used to implement a control plane for a dynamic set of services, where commands are synchronous and errors must be highlighted to the caller rather than ignored.

Prerequisites

• go >= 1.22
• OR docker

Instructions

To build:

go build -o regproxy

To run:

./regproxy

In docker

docker build . -t regproxy
# Set an alias to run as if it was a normal executable
alias regproxy="docker run --rm -it --network=host regproxy"

For command line options see:

regproxy -help

To test:

• start the proxy
• start up 2 http servers on different ports
• register both those servers with the reverse proxy
• make a request to the proxy

regproxy&
python -m http.server 3000&
python -m http.server 3001&
curl -X PUT http://localhost:9876/register -d '{"name": "upstream-1", "callback": "http://localhost:3000"}'
curl -X PUT http://localhost:9876/register -d '{"name": "upstream-2", "callback": "http://localhost:3001"}'
curl http://localhost:9877/

Then you can stop one upstream, and see requests will now fail

kill %1                     # kill the first python server
curl http://localhost:9877/ # Should fail

Extensions:

• Replace the in-memory list with a service discovery system e.g. netflix eureka