mosn / proxy-wasm-go-host

WebAssembly for Proxies (Golang host implementation)

WebAssembly for Proxies (GoLang host implementation)

The GoLang implementation for proxy-wasm, enabling developer to run proxy-wasm extensions in Go.

Run Example

• build and run host

cd example
go run .

• send http request

curl http://127.0.0.1:2045/

• host log

receive request /
print header from server host, User-Agent -> [curl/7.64.1]
print header from server host, Accept -> [*/*]
[http_wasm_example.cc:33]::onRequestHeaders() print from wasm, onRequestHeaders, context id: 2
[http_wasm_example.cc:38]::onRequestHeaders() print from wasm, Accept -> */*
[http_wasm_example.cc:38]::onRequestHeaders() print from wasm, User-Agent -> curl/7.64.1

references

• https://github.com/proxy-wasm/spec
• https://github.com/proxy-wasm/proxy-wasm-cpp-sdk
• https://github.com/proxy-wasm/proxy-wasm-rust-sdk
• https://github.com/tetratelabs/envoy-wasm-rust-sdk
• https://github.com/tetratelabs/proxy-wasm-go-sdk

proxy-wasm-go-host's Issues

Imports/exports don't match expected Proxy-Wasm ABI versions.

Hello!

It was pointed out to me (see: proxy-wasm/proxy-wasm-rust-sdk#104) that Proxy-Wasm Go Host doesn't expose all Proxy-Wasm ABI v0.1.0 hostcalls.

Looking at the code, neither imports nor exports match the specification, e.g. host exports proxy_dispatch_http_call and imports proxy_on_plugin_start, but those don't exists in any of the existing versions (ABI v0.1.0, v0.2.0 or v0.2.1).

I believe that the source of the confusion might be the work-in-progress specification for vNEXT in proxy-wasm/spec, although even that doesn't define proxy_on_plugin_start, so it's unclear to me what's the source for your v1 and v2.

Note that there is no documention for either ABI v0.1.0, v0.2.0 or v0.2.1, so the code in Envoy and Proxy-Wasm SDKs is effectively the specification for those versions.

Change example to use currently maintained ABI (0.2)

Currently, the example points users the wrong way as no SDK is maintaining 0.1 anymore. Is it ok if I change it to something maintained? Ex tinygo with 0.2?

cc @taoyuanyuan @antJack

Ex. here's the current plugin used in tests ported to a currently maintained SDK in go

package main

import (
	"github.com/tetratelabs/proxy-wasm-go-sdk/proxywasm"
	"github.com/tetratelabs/proxy-wasm-go-sdk/proxywasm/types"
)

// build main with `tinygo build -o main.wasm -scheduler=none -target=wasi ./main.go`
func main() {
	proxywasm.SetVMContext(&vmContext{})
}

type vmContext struct {
	// Embed the default VM context here,
	// so that we don't need to reimplement all the methods.
	types.DefaultVMContext
}

// NewPluginContext overrides types.DefaultVMContext.
func (*vmContext) NewPluginContext(contextID uint32) types.PluginContext {
	return &pluginContext{}
}

type pluginContext struct {
	// Embed the default plugin context here,
	// so that we don't need to reimplement all the methods.
	types.DefaultPluginContext
}

// NewHttpContext overrides types.DefaultPluginContext.
func (*pluginContext) NewHttpContext(contextID uint32) types.HttpContext {
	return &httpHeaders{contextID: contextID}
}

type httpHeaders struct {
	// Embed the default http context here,
	// so that we don't need to reimplement all the methods.
	types.DefaultHttpContext
	contextID uint32
}

// OnHttpRequestHeaders overrides types.DefaultHttpContext.
func (ctx *httpHeaders) OnHttpRequestHeaders(numHeaders int, endOfStream bool) types.Action {
	proxywasm.LogDebugf("print from wasm, onRequestHeaders, context id: %d", ctx.contextID)

	hs, err := proxywasm.GetHttpRequestHeaders()
	if err != nil {
		proxywasm.LogCriticalf("failed to get request headers: %v", err)
	}

	for _, h := range hs {
		proxywasm.LogInfof("print from wasm, %s -> %s", h[0], h[1])
	}
	return types.ActionContinue
}

Can you add the implementation and example of wazero?

https://github.com/tetratelabs/wazero

Drop ABI v0.1.0

Per #10 the current code doesn't properly implement v0.1.0, and worse that version isn't really used or maintained anymore. I suggest focusing effort on maintained ABI. Notably this should also drop "wasi_unstable" for "wasi_snapshot_preview1" as that's what's in use by current compilers.

Until this is dropped implementing another host impl is too much low value work, as it is porting for unused and unmaintable ABI.

@taoyuanyuan @antJack FYI I'm pausing efforts until this is done as I am way over budget already and there's no value proceeding if we have to support an incorrect implementation of an unused ABI version.

Add CI

When call ProxyOnRequestHeaders get wrong action

action

cd example and replace the wasm file to new file which handles HTTP headers like this. Then go run . run the example.

expected behaviour

If the header hit, Action::Pause will be returned from wasm side. ActionPause will be returned by the function ProxyOnRequestHeaders.

actual behaviour

Regardless of whether the expected header appears. ActionContinue will be returned by the function ProxyOnRequestHeaders

about the code

I noticed that the action ProxyOnRequestHeaders returned is actually from CallWasmFunction, and res is ignored.

Whether action should be ignored, the value of res should be converted into action format and returned. And what is a.Imports.Wait() actually do, is there any example for it?

Not able to add header element.

I am trying to add a header element to the request OnHttpRequestHeaders. It's not working or an error. Sample call - proxywasm.AddHttpRequestHeader("Debug", "1"), After this call context return back to the caller no instruction are executed.

go get mosn.io/proxy-wasm-go-host/proxywasm/common is failing

I am trying to use this module in my proxy code, while I am running go get I get the following error -
#go get mosn.io/proxy-wasm-go-host/proxywasm/common
#go get: module mosn.io/proxy-wasm-go-host@upgrade found (v0.1.0), but does not contain package mosn.io/proxy-wasm-go-host/proxywasm/common

BufferType extension should be support

err: "proxy_set_buffer_bytes" is not exported in module "env"

When wasm implements the ResponseBody function and is called using v2, an error will be reported

func (ctx *httpContext) OnHttpResponseBody(numHeaders int, endOfStream bool) types.Action {
	proxywasm.ReplaceHttpResponseBody([]byte("proxywasm.ReplaceHttpResponseBody"))
	return types.ActionContinue
}

[wazero][instance] Start failed to instantiate module, err: "proxy_set_buffer_bytes" is not exported in module "env"