I'm trying to create a serverless function for Kong for authentication purposes. I'm required to use a client certificate to authenticate with the remote service that we have to use. I can't seem to get this working and there appears to be no clear documentation on how to do this. I've tried pintsized/lua-resty-http, ngx.socket.tcp(), and luacurl (failed to build) without success. I'm using the newest version of Kong in an Alpine Linux container in case that matters.
What is the best way to do this? Right now I'm considering simply calling curl from within Lua as I know that works, but I was hoping for a better solution that I can do with just Lua/OpenResty.
Thanks.
UPDATE: I just wanted to add, just in case it helps, that I'm already building a new image based on the official Kong one as I had to modify the nginx configuration templates, so installing new software into the container is not an issue.