A template project to demonstrate how to run WebAssembly functions as sidecar microservices in dapr

We would like to create two sidecars that are just wasmedge or wasmedge-tensorflow-lite. Instead of using GO or Rust to implement HTTP servers and then bootstrap wasmedge, we would just run those wasmedge-based server apps in sidecars.

Sidecar #1: implement the grayscale function in Rust.

https://github.com/second-state/wasmedge_wasi_socket/tree/main/examples/http_server

Sidecar #2: implement the tensorflow function in JS

https://github.com/second-state/wasmedge-quickjs#http-request

https://github.com/second-state/wasmedge-quickjs#tensorflow

https://www.secondstate.io/articles/embed-javascript-in-rust/

After that, modify the web port to show all 4 sidecar apps.

I replace the web-port imageHandler func with the following code, to make it easier to observe(making more requests on one click). The memory usage of image-api-go is keeping growing when click classify.

type mock struct {}

func (m *mock)WriteHeader(statusCode int) {
}

func (m *mock)Header() http.Header {
	return nil
}
func (m *mock)Write(b []byte) (int, error) {
	return len(b), nil
}

func imageHandler(w http.ResponseWriter, r *http.Request) {
	println("imageHandler ....")
	body, err := ioutil.ReadAll(r.Body)

	if err != nil {
		println("error: ", err.Error())
		panic(err)
	}
	api := r.Header.Get("api")
	if api == "go" {
		daprClientSend(body, w)
		for i:=0;i<10;i++ {
			go func() {
				for i:=0;i<10;i++ {
					daprClientSend(body, &mock{})
				}
			}()
		}
	} else {
		httpClientSend(body, w)
	}
}

The current example uses wasm-bindgen to pass call parameters from the GO app to the WASM function. However, wasm-bindgen does not work with the Rust WASI target since Rust version 1.51. We now have a better solution for bindgen since WasmEdge 0.9.0. It is called wasmedge-bindgen:

https://wasmedge.org/book/en/embed/go/function.html

Can we refactor the GO host example to use wasmedge-bindgen?

The grayscale service only supports the GIF and PNG formats. But the classify service only supports the JPG format. Can we make them consistent?

Perhaps supports JPGs by default in both services? Thanks.

I have configured GitHub Pages to serve from the main branch's root directory. So, our static web page is now available here:

https://second-state.github.io/dapr-wasm/web/

We do not actually need a GitHub Action for this. As soon as we update the main branch, it will be automatically deployed.

We could, however, to use GitHub Actions to copy just the /web folder to another branch (e.g., gh-pages) and then deploy the gh-pages branch as the web site's root.

The WasmEdge GO SDK allows developers to register host functions to the runtime, and create a customized version of WasmEdge that includes the host functions.

We should add Dapr GO SDK functions into a customized version of WasmEdge.

We should then create Rust APIs for those Dapr host functions so that WasmEdge app developers can use them.

Hi,

I am performing the grayscale tutorial example i.e. make run-api-rs the following error is occurring.

ERRO[0000] error getting topics from app: unexpected end of JSON input  app_id=image-api-rs instance=wasm-oci-demo scope=dapr.runtime type=log ver=1.4.2
ERRO[0000] error occurred while beginning pubsub messages: error getting topics from app: unexpected end of JSON input  app_id=image-api-rs instance=wasm-oci-demo scope=dapr.runtime type=log ver=1.4.2
INFO[0000] dapr initialized. Status: Running. Init Elapsed 9.416037000000001ms  app_id=image-api-rs instance=wasm-oci-demo scope=dapr.runtime type=log ver=1.4.2

The following video (which starts just as the error occurs) demonstrates the above error in action.

https://youtu.be/A5EhO7cNTCw?t=392

It seems that dapr list is displaying the correct output (in terms of apps, ports etc.)

wasmedge@wasm-oci-demo:~$ dapr list
  APP ID        HTTP PORT  GRPC PORT  APP PORT  COMMAND               AGE  CREATED              PID     
  go-web-port   3500       40659      8080      ./web-port            36s  2021-10-05 02:38.25  334410  
  image-api-rs  3502       34493      9004      ./target/debug/im...  23s  2021-10-05 02:38.38  334530  
  image-api-go  3501       40639      9003      ./image-api-go        9s   2021-10-05 02:38.52  334658 

Is it possible that the grayscale needs to be added to the config i.e. https://github.com/second-state/dapr-wasm/blob/main/config/conf.json

Any suggestions would be greatly appreciated.

Thanks Tim

reoslve Mismatched function type. Expected: FuncType {params{i32 , i32 , i32} returns{i32}} , Got: FuncType {params{i32 , i32} returns{i32}} issue: #25

https://github.com/second-state/dapr-wasm/blob/main/image-api-go/image_api.go#L50 The resource loaded seems not exist. Besides would you mind provide the code before compiling into wasm?

I see there are multiple article link to this repo with obsolete information: https://www.infoq.com/articles/webassembly-dapr-wasmedge/?utm_source=email&utm_medium=Web-Development&utm_campaign=newsletter&utm_content=11162021 https://wasmedge.org/book/en/use_cases/frameworks/mesh/dapr.html

It seems above links are having a Golang microservice, I think it's better if you can maintain both repo or update again the article. Thanks