Added producer template

src/code_generator/templates/producer_nats/main.go

@@ -0,0 +1,81 @@
+//go:generate go run github.com/bytecodealliance/wasm-tools-go/cmd/wit-bindgen-go generate --world hello --out gen ./wit
+package main
+
+import (
+	"fmt"
+	"net/http"
+
+	logger "gitea.rebus.ninja/lore/wasm-nats-producer-client/gen/wasi/logging/logging"
+	"gitea.rebus.ninja/lore/wasm-nats-producer-client/gen/wasmcloud/messaging/consumer"
+	"gitea.rebus.ninja/lore/wasm-nats-producer-client/gen/wasmcloud/messaging/handler"
+	"gitea.rebus.ninja/lore/wasm-nats-producer-client/gen/wasmcloud/messaging/types"
+	"github.com/bytecodealliance/wasm-tools-go/cm"
+	"go.wasmcloud.dev/component/net/wasihttp"
+)
+
+type messagingConsumerAdapter struct {
+	Publish func(msg types.BrokerMessage) (result cm.Result[string, struct{}, string])
+}
+
+// NOTE(lxf): this is overridden in tests
+var messagingConsumer = &messagingConsumerAdapter{
+	Publish: consumer.Publish,
+} 
+
+
+func init() {
+	wasihttp.HandleFunc(handleHttp)
+	handler.Exports.HandleMessage = handleMessage
+}
+
+func handleHttp(w http.ResponseWriter, r *http.Request) {
+
+	// get body as string
+	if handleRequest(r.FormValue("data")) {
+		fmt.Fprintf(w, "Message sent!\n")
+	} else {
+		fmt.Fprintf(w, "Error\n") 
+	}
+
+	// send response
+}
+
+func handleMessage(msg types.BrokerMessage) cm.Result[string, struct{}, string]{
+
+	logger.Log(logger.LevelInfo,"MessageHandler", "Received message on subject" + msg.Subject)
+
+	arg := cm.LiftString[string, *uint8, uint8](msg.Body.Data(), uint8(msg.Body.Len()))
+
+	if handleRequest(arg) {
+		cm.OK[cm.Result[string, struct{}, string]](struct{}{})
+	}
+
+	return cm.Err[cm.Result[string, struct{}, string]]("Couldn't send message to topic")
+}
+
+func handleRequest(arg string) bool {
+	
+	// TODO implement the logic to get the destination topic from the config
+	// dest_topic := config.GetAll()
+	dest_topic := "{{ dest_topic }}"
+
+	result := exec_task(arg)
+
+	// Send reply
+	reply := types.BrokerMessage{
+		Subject: dest_topic,
+		Body:    cm.ToList([]byte(result)),
+		ReplyTo: cm.None[string](),
+	}
+	res := messagingConsumer.Publish(reply)
+	if res.IsErr() {
+		logger.Log(logger.LevelError, "MessageHandler", "Failed to send reply, error: " + *res.Err())
+		return false
+	}
+
+	return true
+}
+
+// Since we don't run this program like a CLI, the `main` function is empty. Instead,
+// we call the `handleRequest` function when an HTTP request is received.
+func main() {}