Example of host function in wasm.runtine.v8 for a wasm rust filter?

[leandrocurioso]

Title: Example of host function in wasm.runtine.v8 for a wasm rust filter?

Description:
I need to have a large dataset available to all wasm rust filters

I tried top pass the large data as a configuration for the wasm vm. (Bad idea! Since there is more then 1 VM the configuration gets duplicated and uses a lot of memory).

I think the approach should be to handle this large data set in the host (envoy) and call host functions to get what I need.

The whole idea is that I need in the wasm filter get a http header and match against a large list.

Can you guys send me an example repo or article of how to build this kind of host function?
Is the whole thinking about how to tackle this ok? Any suggestions?

Thanks in advance!

[krinkinmu]

@leandrocurioso

I did create a custom host function in one of the experiments I did, here is a commit that did that (among other things): krinkinmu@3581a81. The relevant bit is in source/extensions/common/wasm/foreign.cc it seems rather straightforward to add a function like that.

Hope this might help you get started.

[leandrocurioso]

@leandrocurioso

I did create a custom host function in one of the experiments I did, here is a commit that did that (among other things): krinkinmu@3581a81. The relevant bit is in source/extensions/common/wasm/foreign.cc it seems rather straightforward to add a function like that.

Hope this might help you get started.

Thanks a lot man! This will for sure help =]