Wasm middleware: add ability to pass config to guest

[Taction]

Description

Add config for http wasm middleware.
Wasm code can get this configuration via handler.Host.GetConfig(), examples in middleware/http/wasm/internal/e2e-guests/config/main.go.

Also, fix some inconsistencies in the benchmark tests.

Issue reference

We strive to have all PR being opened based on an issue, where the problem or feature have been discussed prior to implementation.

Please reference the issue this PR will close: #2917

Checklist

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• Code compiles correctly
• Created/updated tests
• Extended the documentation / Created issue in the https://github.com/dapr/docs/ repo: Docs for http wasm middleware guest config docs#3617

[yaron2]

@codefromthecrypt can you please take a look?

[codefromthecrypt]

Looks good as only minor things. Like usual we need the docs updated with text on what "config" means because plain property names are ambiguous (e.g. is this the guest or is this the host?)

[codefromthecrypt]

can you raise a PR upstream to coerce empty to nil?

[Taction]

When writing into memory, the upstream has checked the len of config bytes, does it necessary to coerce empty to nil?

// getConfig implements the WebAssembly host function handler.FuncGetConfig.
func (m *middleware) getConfig(_ context.Context, mod wazeroapi.Module, stack []uint64) {
	buf := uint32(stack[0])
	bufLimit := handler.BufLimit(stack[1])

	configLen := writeIfUnderLimit(mod.Memory(), buf, bufLimit, m.guestConfig)

	stack[0] = uint64(configLen)
}

func writeIfUnderLimit(mem wazeroapi.Memory, offset, limit handler.BufLimit, v []byte) (vLen uint32) {
	vLen = uint32(len(v))
	if vLen > limit {
		return // caller can retry with a larger limit
	} else if vLen == 0 {
		return // nothing to write
	}
	mem.Write(offset, v)
	return
}

[Taction]

Thanks, I will open a doc issue and pr soon.

[codefromthecrypt]

only request is to revert the change to the other binaries so that we don't thrash git with binary changes. I think tinygo isn't 100pct idempotent, and we only changed the config one (new one)

[ItalyPaleAle]

LGTM but can you please add the copyright headers?

Also, does the binding need the configuration too?

[evacchi]

I think this PR only needs to rebase

[ItalyPaleAle]

@Taction is this ready to be merged? Does the binding need configuration too?

[Taction]

@ItalyPaleAle This is ready to be merged. The binding doesn't need this.

[ItalyPaleAle]

@Taction ok I’ll merge once CI is green.

why do bindings not need this?

[Taction]

For middleware, since it can not access the env and file system, there needs a way for wasm code to get the configuration.
For binding, it accepts request data as stdin and request metadata as cli args, this is flexible enough to allow the application to pass request data and configuration information to the binding wasm code. So I think it is ok to not add this unless there are any end users that want a similar way to pass global configurations.

[codefromthecrypt]

well put @Taction. In technical terms, there are no ABI requirements for binding as it should be fully described via the command/exec pattern.