how do I get upstream host in serverless-pre-function?

[dark-code]

1. how do I get upstream host in serverless-pre-function?
2. where is the api doc?

[tokers]

how do I get upstream host in serverless-pre-function?

For getting the upstream host, you may need to read codes in apisix/upstream.lua and check how APISIX calculates the upstream host.

where is the api doc?

Which API? We have the API spec for Admin API and Control API.

[dark-code]

api doc means :when we develope a plugin（or write a pre function） which function I can use and how to use 。just like javadoc

[dark-code]

I already check many times apisix/upstream.lua but don't find any function can use to get upstream or upstream's node host info