support compile set-ns to wasm

Author: Mengqi Yu

functions/go/set-namespace/main.go

@@ -15,13 +15,10 @@ package main
 
 import (
 	"os"
-
-	"github.com/GoogleContainerTools/kpt-functions-catalog/functions/go/set-namespace/transformer"
-	"github.com/GoogleContainerTools/kpt-functions-sdk/go/fn"
 )
 
 func main() {
-	if err := fn.AsMain(fn.ResourceListProcessorFunc(transformer.Run)); err != nil {
+	if err := run(); err != nil {
 		os.Exit(1)
 	}
 }

functions/go/set-namespace/run.go

@@ -0,0 +1,26 @@
+// Copyright 2022 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build !(js && wasm)
+
+package main
+
+import (
+	"github.com/GoogleContainerTools/kpt-functions-catalog/functions/go/set-namespace/transformer"
+	"github.com/GoogleContainerTools/kpt-functions-sdk/go/fn"
+)
+
+func run() error {
+	return fn.AsMain(fn.ResourceListProcessorFunc(transformer.Run))
+}

functions/go/set-namespace/run_js.go

@@ -0,0 +1,56 @@
+// Copyright 2022 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build js && wasm
+
+package main
+
+import (
+	// Work around https://github.com/prep/wasmexec/issues/3 until it is resolved upstream.
+	// This should be the first one among all imports.
+	_ "github.com/GoogleContainerTools/kpt-functions-catalog/functions/go/set-namespace/setosargs"
+
+	"fmt"
+	"syscall/js"
+
+	"github.com/GoogleContainerTools/kpt-functions-catalog/functions/go/set-namespace/transformer"
+	"github.com/GoogleContainerTools/kpt-functions-sdk/go/fn"
+)
+
+func run() error {
+	js.Global().Set("processResourceList", resourceListProcessorWrapper())
+	<-make(chan bool)
+	return nil
+}
+
+func transformNamespace(input []byte) ([]byte, error) {
+	return fn.Run(fn.ResourceListProcessorFunc(transformer.Run), []byte(input))
+}
+
+func resourceListProcessorWrapper() js.Func {
+	// TODO: figure out a better way to surface a golang error to JS environment.
+	// Currently error is surfaced as a string.
+	jsonFunc := js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+		if len(args) != 1 {
+			return "Invalid number of arguments passed"
+		}
+		input := args[0].String()
+		transformed, err := transformNamespace([]byte(input))
+		if err != nil {
+			return fmt.Errorf("unable to process resource list:", err.Error())
+		}
+		return string(transformed)
+	})
+	return jsonFunc
+}

functions/go/set-namespace/setosargs/setosargs.go

@@ -0,0 +1,26 @@
+// Copyright 2022 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package setosargs
+
+import (
+	"os"
+)
+
+// Work around https://github.com/prep/wasmexec/issues/3 until it is resolved upstream.
+func init() {
+	if len(os.Args) == 0 {
+		os.Args = []string{"kpt-fn-wasm"}
+	}
+}