Gas Calculation per function

[AchalaSB]

Can we calculate Cost for each function using go-wasmer?( something like ethereum is doing)
Ex: if we are executing simple rust code to add two numbers, need to know the cost for + operator.

I see there are implementation in wasmer/pull/450
But didn't get how exactly cost is calculating. where is cost table here?
Is there any doc to understand this?

Thanks

[AdamSLevy]

The docs on metering are very sparse. The implementation in Rust is here: https://github.com/wasmerio/wasmer/blob/master/lib/middleware-common/src/metering.rs

That is some middleware that injects metering code at module compilation. This functionality is not exposed in either the Go or C APIs in the main release of wasmer and this library, unfortunately. It's not impossible to get it working though. A number of branches that are a little stale now, but work, are out there that implement the necessary APIs in the Rust -> C bridge and C -> Go bridge.

Another thing to be aware of is that the metering as currently implemented is buggy and can miss some functions that exceed the set limit. See wasmerio/wasmer#999

[Hywan]

We can make it a higher priority. As @AdamSLevy said, we must first support middleware in the C API, then in Go.

[Rathil]

@Hywan Tell me, is there a plan to add this functionality?

[hnfgns]

@Hywan adding this to C runtime is a great idea. one can look at this issue as an important enhancement to the security model currently offered. hosts can prevent some attack vectors through this feature imo.

[alanorwick]

Any update on this?