chore(wasm): add Go SDK (#3059)

src/wasm_sdk/go/README.md

@@ -0,0 +1,6 @@
+# Dragonfly Go SDK for wasm
+
+1. Download tiny go
+2. Compile with wasi as target: `tinygo build -o go.wasm -target=wasi example.go`
+3. Load the module at startup via `WASMPATH`
+4. Call an exported function via `WASMCALL go.wasm go_hi`

src/wasm_sdk/go/example.go

@@ -0,0 +1,49 @@
+package main
+
+import "encoding/binary"
+import "strings"
+
+var buffer []byte
+
+//export provide_buffer
+func provide_buffer(bytes int) *byte {
+  buffer = []byte(strings.Repeat("x", bytes))
+  return &buffer[0]
+}
+
+//go:wasm-module dragonfly
+//export call
+func call(str *byte)
+
+func toByteArray(i int) (arr []byte) {
+    arr = []byte("xxxx")
+    binary.LittleEndian.PutUint32(arr[0:4], uint32(i))
+    return
+}
+
+func send(args... string) string {
+  var data []byte
+  data = append(data, toByteArray(len(args))...)
+  data = data[0:4]
+
+  for _, element := range args {
+    var sz = toByteArray(len(element))
+    var payload = []byte(element)
+    data = append(data, sz...)
+    data = append(data, payload...)
+  }
+
+  call(&data[0])
+  return string(buffer)
+}
+
+//export go_hi
+func go_hi() {
+  var res = send("set", "foo", "bar");
+  println("Result is ", res)
+  res = send("get", "foo");
+  println("Result is ", res)
+}
+
+// main is required for the `wasi` target, even if it isn't used.
+func main() {}