Adds wasi standard adapters to the go package

.gitignore

@@ -7,6 +7,10 @@
 *.dll
 *.so
 *.dylib
+*.wasm
+
+# Scratch directory used by regenerate_bindings.sh
+tmp/
 
 # Test binary, built with `go test -c`
 *.test

.golangci.yml

@@ -0,0 +1,8 @@
+version: "2"
+
+linters:
+  exclusions:
+    # The wit-bindgen header ("Generated by `wit-bindgen` ... DO NOT EDIT!")
+    # doesn't match the strict Go convention regex, so use the lenient
+    # heuristic to skip the generated bindings in imports/ and exports/.
+    generated: lenient

README.md

@@ -1,7 +1,7 @@
 <div align="center">
   <h1><code>go-pkg</code></h1>
   <p>
-    <strong>Golang packages for the Bytecode Alliance <a href="https://github.com/bytecodealliance/componentize-go">componentize-go</a> project</strong>
+    <strong>The Go library for building WebAssembly components with <a href="https://github.com/bytecodealliance/componentize-go">componentize-go</a></strong>
   </p>
   <strong>A <a href="https://bytecodealliance.org/">Bytecode Alliance</a> project</strong>
   <p>
@@ -15,13 +15,115 @@
 
 # Overview
 
-This is a set of Golang packages for the Bytecode Alliance componentize-go project.
+Module `go.bytecodealliance.org/pkg` is the Go library for Wasm components. It adapts standard-library interfaces (`net/http`, `log/slog`) to standard `wasi:*` interfaces and ships the committed bindings and WIT worlds needed to build HTTP components with [componentize-go](https://github.com/bytecodealliance/componentize-go). The use of this package significantly reduces the number of files generated and committed for a typical go application.
+
+The library targets two worlds defined in [`wit/world.wit`](./wit/world.wit):
+
+- **`bytecodealliance:pkg/wasip2`** (default): a sync WASI P2 component exporting `wasi:http/incoming-handler@0.2.8`, buildable with stock Go.
+- **`bytecodealliance:pkg/wasip3`** (opt-in): an async WASI P3 component exporting `wasi:http/handler@0.3.0` with streaming bodies and native concurrency.
+
+## Packages
+
+| Package | Description |
+| --- | --- |
+| `wasihttp` | `net/http` adapter for `wasi:http`: serve incoming requests with a standard `http.Handler` and send outbound requests through an `http.RoundTripper`. One API, two implementations selected by build tag (see below). |
+| `wasilog` | `slog.Handler` implementation over `wasi:logging`. |
+| `wasiconfig` | Helpers over `wasi:config/store`. |
+| `wit/types`, `wit/runtime`, `wit/async` | Core WIT value types (option, result, tuple, stream, future) and the canonical-ABI runtime support used by generated bindings. |
+| `imports/...` | Committed generated bindings for the `wasi:*` interfaces imported by the two worlds (both the 0.2.8 and 0.3.0 families). |
+| `exports/...` | Per-world generated `//go:wasmexport` glue and export trampolines. |
+
+Bindings under `imports/` and `exports/` are generated by
+[`regenerate_bindings.sh`](./regenerate_bindings.sh) — do not edit them.
+
+## Updating WIT dependencies
+
+The `wasi:*` WIT packages under `wit/deps/` are vendored verbatim from the WebAssembly package registry using [wkg](https://github.com/bytecodealliance/wasm-pkg-tools). To update a dependency:
+
+1. Bump its version in [`fetch_wit_deps.sh`](./fetch_wit_deps.sh) and in
+   [`wit/world.wit`](./wit/world.wit).
+2. Re-fetch the vendored WIT:
+
+   ```console
+   $ ./fetch_wit_deps.sh
+   ```
+
+3. Regenerate the committed bindings and commit everything together:
+
+   ```console
+   $ ./regenerate_bindings.sh
+   ```
+
+> **Note**: the script uses `wkg get` with exact versions rather than
+> `wkg wit fetch` because the library intentionally depends on two versions
+> of several packages (e.g. `wasi:http@0.2.8` and `wasi:http@0.3.0`), and
+> `wkg wit fetch` resolves at most one version per package name.
+
+## The `componentizego_async` build tag
+
+`wasihttp` compiles to one of two implementations; the exported API is identical under both:
+
+- **Default (no tag)**: sync WASI P2 (`wasi:http@0.2.8`). Matches the `bytecodealliance:pkg/wasip2` world.
+- **`-tags componentizego_async`**: async WASI P3 (`wasi:http@0.3.0`) with streaming bodies and native concurrency. Matches the   `bytecodealliance:pkg/wasip3` world.
+
+componentize-go sets the tag automatically when building an async world.
+
+## Quickstart
+
+```go
+package main
+
+import (
+	"net/http"
+
+	"go.bytecodealliance.org/pkg/wasihttp"
+)
+
+func init() {
+	wasihttp.HandleFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Write([]byte("Hello, component!"))
+	})
+}
+
+func main() {}
+```
+
+Add componentize-go as a Go tool and build:
+
+```console
+$ go get -tool github.com/bytecodealliance/componentize-go
+$ go tool componentize-go build
+```
+
+The default world (`bytecodealliance:pkg/wasip2@0.1.0`) is declared in [`componentize-go.toml`](./componentize-go.toml) and discovered automatically. To build the async WASI P3 world instead:
+
+```console
+$ go tool componentize-go -w bytecodealliance:pkg/wasip3 build
+```
+
+## Benchmarks
+
+Pure-Go conversion logic (header conversion and friends) has microbenchmarks that run on the host:
+
+```console
+$ go test -bench=. -benchmem ./...
+```
+
+Packages that call `wasi:*` imports only link on wasm targets, so the benchmarks live in host-compilable packages (e.g. `internal/httpconv`).
+
+For A/B comparisons use [benchstat](https://pkg.go.dev/golang.org/x/perf/cmd/benchstat): collect ≥10 samples per side with the test filter disabled, then compare:
+
+```console
+$ go test -bench=. -benchmem -count=10 -run='^$' ./... > old.txt
+$ # ... apply your change ...
+$ go test -bench=. -benchmem -count=10 -run='^$' ./... > new.txt
+$ benchstat old.txt new.txt
+```
 
 ## Questions?
 
 Ask over in the Bytecode Alliance <a href="https://bytecodealliance.zulipchat.com">Zulip</a>.
 
 ## Contributing
 
-See [CONTRIBUTING.md](./CONTRIBUTING.md) for more information about contributing
-to this repository.
+See [CONTRIBUTING.md](./CONTRIBUTING.md) for more information about contributing to this repository.

componentize-go.toml

@@ -0,0 +1,9 @@
+# Default world for components built against this library. componentize-go
+# discovers this file via `go list -m all`, so `go tool componentize-go
+# build` needs no flags in consuming apps.
+#
+# The default is the sync WASI P2 world, which builds with stock Go. To
+# target the async WASI P3 world instead, build with:
+#   componentize-go -w bytecodealliance:pkg/wasip3 build
+worlds = ["bytecodealliance:pkg/wasip2@0.1.0"]
+wit_paths = ["wit"]

exports/bytecodealliance_pkg_wasip2_0_1_0/export_wasi_http_0_2_8_incoming_handler/handler.go

@@ -0,0 +1,17 @@
+// Package export_wasi_http_0_2_8_incoming_handler is the export trampoline
+// for the sync `wasip2` world's `wasi:http/incoming-handler@0.2.8` export.
+// The generated wit_exports glue calls Handle; the library's wasihttp
+// package assigns Exports.Handle at init time.
+package export_wasi_http_0_2_8_incoming_handler
+
+import (
+	"go.bytecodealliance.org/pkg/imports/wasi_http_0_2_8_types"
+)
+
+var Exports struct {
+	Handle func(request *wasi_http_0_2_8_types.IncomingRequest, responseOut *wasi_http_0_2_8_types.ResponseOutparam)
+}
+
+func Handle(request *wasi_http_0_2_8_types.IncomingRequest, responseOut *wasi_http_0_2_8_types.ResponseOutparam) {
+	Exports.Handle(request, responseOut)
+}

exports/bytecodealliance_pkg_wasip2_0_1_0/wit_exports/empty.s

@@ -0,0 +1,3 @@
+// This file exists for testing this package without WebAssembly,
+// allowing empty function bodies with a //go:wasmimport directive.
+// See https://pkg.go.dev/cmd/compile for more information.

exports/bytecodealliance_pkg_wasip2_0_1_0/wit_exports/wit_exports.go

@@ -0,0 +1,39 @@
+// Generated by `wit-bindgen` 0.59.0. DO NOT EDIT!
+//
+// This code was generated from the following packages:
+//     wasi:io@0.2.8
+//     wasi:clocks@0.2.8
+//     wasi:filesystem@0.2.8
+//     wasi:sockets@0.2.8
+//     wasi:random@0.2.8
+//     wasi:cli@0.2.8
+//     wasi:config@0.2.0-rc.1
+//     wasi:logging@0.1.0-draft
+//     wasi:http@0.2.8
+//     wasi:clocks@0.3.0
+//     wasi:filesystem@0.3.0
+//     wasi:sockets@0.3.0
+//     wasi:random@0.3.0
+//     wasi:cli@0.3.0
+//     wasi:http@0.3.0
+//     bytecodealliance:pkg@0.1.0
+
+package wit_exports
+
+import (
+	"go.bytecodealliance.org/pkg/exports/bytecodealliance_pkg_wasip2_0_1_0/export_wasi_http_0_2_8_incoming_handler"
+	"go.bytecodealliance.org/pkg/imports/wasi_http_0_2_8_types"
+	witRuntime "go.bytecodealliance.org/pkg/wit/runtime"
+	"runtime"
+)
+
+var staticPinner = runtime.Pinner{}
+var exportReturnArea = uintptr(witRuntime.Allocate(&staticPinner, 0, 1))
+var syncExportPinner = runtime.Pinner{}
+
+//go:wasmexport wasi:http/incoming-handler@0.2.8#handle
+func wasm_export_wasi_http_0_2_8_incoming_handler_handle(arg0 int32, arg1 int32) {
+
+	export_wasi_http_0_2_8_incoming_handler.Handle(wasi_http_0_2_8_types.IncomingRequestFromOwnHandle(int32(uintptr(arg0))), wasi_http_0_2_8_types.ResponseOutparamFromOwnHandle(int32(uintptr(arg1))))
+
+}

exports/bytecodealliance_pkg_wasip3_0_1_0/export_wasi_http_0_3_0_handler/handler.go

@@ -0,0 +1,18 @@
+// Package export_wasi_http_0_3_0_handler is the export trampoline for the
+// async `wasip3` world's `wasi:http/handler@0.3.0` export. The generated
+// wit_exports glue calls Handle; the library's wasihttp package assigns
+// Exports.Handle at init time.
+package export_wasi_http_0_3_0_handler
+
+import (
+	"go.bytecodealliance.org/pkg/imports/wasi_http_0_3_0_types"
+	witTypes "go.bytecodealliance.org/pkg/wit/types"
+)
+
+var Exports struct {
+	Handle func(request *wasi_http_0_3_0_types.Request) witTypes.Result[*wasi_http_0_3_0_types.Response, wasi_http_0_3_0_types.ErrorCode]
+}
+
+func Handle(request *wasi_http_0_3_0_types.Request) witTypes.Result[*wasi_http_0_3_0_types.Response, wasi_http_0_3_0_types.ErrorCode] {
+	return Exports.Handle(request)
+}

exports/bytecodealliance_pkg_wasip3_0_1_0/wit_exports/empty.s

@@ -0,0 +1,3 @@
+// This file exists for testing this package without WebAssembly,
+// allowing empty function bodies with a //go:wasmimport directive.
+// See https://pkg.go.dev/cmd/compile for more information.