Dapr SDK for WebAssembly

Written in Rust, the dapr_sdk_wasi crate can be compiled into WebAssembly and runs in the WasmEdge Runtime.

Introduction | How it works | Contribution

Introduction

This software is still under development, we welcome new contributors!

WebAssembly provides a secure, fast, and lightweight runtime sandbox for cloud-native applications, especially for microservices, as an alternative to Linux containers and VMs. The dapr_sdk_wasi crate is a Rust SDK for the Dapr framework. It provides an easy way for Rust-based microservices in WasmEdge to interact with Dapr APIs and sidecar services. The figure below shows a Dapr-enabled microservice running inside the WasmEdge sandbox.

Currently, the dapr-sdk-wasi supports Dapr's service invocation, state management, secrets, and health APIs.

Dapr API	Status
Service invocation API	✅
State management API	✅
Pub/sub API	To be done
Bindings API	To be done
Actors API	To be done
Secrets API	✅
Configuration API	To be done
Distributed Lock API	To be done
Health API	✅
Metadata API	To be done

How it works

This repo contains the SDK, a Dapr service example, and an example client to access the Dapr service using the SDK.

• The root project is the SDK, which is provides a Rust API to call Dapr API services.
• examples/echo is a microservice demo that runs with a Dapr sidecar.
• examples/tests is a SDK client that accesses Dapr APIs on the sidecar.

If you want to run the echo example and SDK tests, follow the following instructions.

Install Rust and add Wasi target for the Rust compiler

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
rustup target add wasm32-wasi

Install WasmEdge

curl -sSf https://raw.githubusercontent.com/WasmEdge/WasmEdge/master/utils/install.sh | bash

Install and init Dapr

wget -q https://raw.githubusercontent.com/dapr/cli/master/install/install.sh -O - | /bin/bash
dapr init

Run the echo example

cd examples/echo

// compile the rust code to wasm 
cargo build --target wasm32-wasi --release
wasmedgec target/wasm32-wasi/release/dapr_echo.wasm dapr_echo.wasm

// Use Dapr to start the echo microservice application
dapr run --app-id echo-service --app-protocol http --app-port 9004 --dapr-http-port 3502 --components-path ../config --log-level debug wasmedge dapr_echo.wasm

// Shows the server log
ℹ️  Starting Dapr with id echo-service. HTTP Port: 3502. gRPC Port: 44517
time="2022-10-07T22:00:17.732779744Z" level=info msg="starting Dapr Runtime -- version 1.8.4 -- commit 18575823c74318c811d6cd6f57ffac76d5debe93" app_id=echo-service instance=fv-az186-200 scope=dapr.runtime type=log ver=1.8.4
time="2022-10-07T22:00:17.732813444Z" level=info msg="log level set to: debug" app_id=echo-service instance=fv-az186-200 scope=dapr.runtime type=log ver=1.8.4
···

Run the SDK tests

Do the following from another terminal window from the echo service.

cd examples/tests

// compile the SDK testing code to wasm
cargo build --target wasm32-wasi --release
wasmedgec target/wasm32-wasi/release/dapr_examples.wasm dapr_examples.wasm

// Run the tests to interact with the `echo` service's Dapr sidecar from WasmEdge
wasmedge dapr_examples.wasm

// Results from the tests on the console
URL is http://localhost:3502/v1.0/healthz/
Status code is 204
Dapr echo is healthy!
URL is http://localhost:3502/v1.0/invoke/echo-service/method/echo
Echo: {"message":"WasmEdge"}
URL is http://localhost:3502/v1.0/state/starwars
Saved!
URL is http://localhost:3502/v1.0/state/starwars/weapon
State for weapon: "DeathStar"
URL is http://localhost:3502/v1.0/state/starwars/bulk
State for weapon and planet: [{"data":"DeathStar","etag":"1","key":"weapon"},{"data":{"name":"Tatooine"},"etag":"1","key":"planet"}]
URL is http://localhost:3502/v1.0/state/starwars/weapon
Deleted!
URL is http://localhost:3502/v1.0/state/starwars/bulk
State for weapon and planet: [{"key":"weapon"},{"data":{"name":"Tatooine"},"etag":"1","key":"planet"}]
URL is http://localhost:3502/v1.0/state/starwars/transaction
Transacted!
URL is http://localhost:3502/v1.0/state/starwars/bulk
State for weapon, planet, key1 and key2: [{"key":"weapon"},{"data":{"name":"Tatooine"},"etag":"1","key":"planet"},{"data":"myData","etag":"1","key":"key1"},{"key":"key2"}]
URL is http://localhost:3502/v1.0/secrets/local-store/DB_URL:MYSQL
Secret for DB_URL:MYSQL {"DB_URL:MYSQL":"***127.0.0.1:3306/mysql"}

Contribution

Any feedback is appreciated. If you have any questions or suggestions, please raise an issue or create a PR and let us know.

If you prefer chatting in real-time, join our Discord server.

Tech stacks used in this project

• Tokio
• hyper
• reqwest
• Dapr
• WasmEdge