Add lambda runtime support (#70)

Summary:
This PR adds the support to run the user services on Amazon Lambda

Author: muhamadazmy

Cargo.toml

@@ -22,6 +22,7 @@ default = ["http_server", "rand", "uuid", "tracing-span-filter"]
 hyper = ["dep:hyper", "http-body-util", "restate-sdk-shared-core/http"]
 http_server = ["hyper", "hyper/server", "hyper/http2", "hyper-util", "tokio/net", "tokio/signal", "tokio/macros"]
 tracing-span-filter = ["dep:tracing-subscriber"]
+lambda = [ "dep:http-serde", "dep:lambda_runtime", "dep:aws_lambda_events"]
 
 [dependencies]
 bytes = "1.10"
@@ -44,6 +45,9 @@ tokio = { version = "1.44", default-features = false, features = ["sync"] }
 tracing = "0.1"
 tracing-subscriber = { version = "0.3", features = ["registry"], optional = true }
 uuid = { version = "1.16.0", optional = true }
+http-serde = { version = "2.1.1", optional = true }
+aws_lambda_events = { version = "0.16.1", optional = true }
+lambda_runtime = { version = "0.14.2", optional = true }
 
 [dev-dependencies]
 tokio = { version = "1", features = ["full"] }

README.md

@@ -10,11 +10,11 @@
 
 ## Community
 
-* 🤗️ [Join our online community](https://discord.gg/skW3AZ6uGd) for help, sharing feedback and talking to the community.
-* 📖 [Check out our documentation](https://docs.restate.dev) to get quickly started!
-* 📣 [Follow us on Twitter](https://twitter.com/restatedev) for staying up to date.
-* 🙋 [Create a GitHub issue](https://github.com/restatedev/sdk-java/issues) for requesting a new feature or reporting a problem.
-* 🏠 [Visit our GitHub org](https://github.com/restatedev) for exploring other repositories.
+- 🤗️ [Join our online community](https://discord.gg/skW3AZ6uGd) for help, sharing feedback and talking to the community.
+- 📖 [Check out our documentation](https://docs.restate.dev) to get quickly started!
+- 📣 [Follow us on Twitter](https://twitter.com/restatedev) for staying up to date.
+- 🙋 [Create a GitHub issue](https://github.com/restatedev/sdk-java/issues) for requesting a new feature or reporting a problem.
+- 🏠 [Visit our GitHub org](https://github.com/restatedev) for exploring other repositories.
 
 ## Using the SDK
 
@@ -58,6 +58,75 @@ async fn main() {
 }
 ```
 
+## Running on Lambda
+
+The Restate Rust SDK supports running services on AWS Lambda using Lambda Function URLs. This allows you to deploy your Restate services as serverless functions.
+
+### Setup
+
+First, enable the `lambda` feature in your `Cargo.toml`:
+
+```toml
+[dependencies]
+restate-sdk = { version = "0.1", features = ["lambda"] }
+tokio = { version = "1", features = ["full"] }
+```
+
+### Basic Lambda Service
+
+Here's how to create a simple Lambda service:
+
+```rust
+use restate_sdk::prelude::*;
+
+#[restate_sdk::service]
+trait Greeter {
+    async fn greet(name: String) -> HandlerResult<String>;
+}
+
+struct GreeterImpl;
+
+impl Greeter for GreeterImpl {
+    async fn greet(&self, _: Context<'_>, name: String) -> HandlerResult<String> {
+        Ok(format!("Greetings {name}"))
+    }
+}
+
+#[tokio::main]
+async fn main() {
+    // To enable logging/tracing
+    // check https://docs.aws.amazon.com/lambda/latest/dg/rust-logging.html#rust-logging-tracing
+
+    // Build and run the Lambda endpoint
+    LambdaEndpoint::run(
+        Endpoint::builder()
+            .bind(GreeterImpl.serve())
+            .build(),
+    )
+    .await
+    .unwrap();
+}
+```
+
+### Deployment
+
+1. Install `cargo-lambda`
+   ```
+   cargo install cargo-lambda
+   ```
+2. Build your Lambda function:
+
+   ```bash
+   cargo lambda build --release --arm64 --output-format zip
+   ```
+
+3. Create a Lambda function with the following configuration:
+
+   - **Runtime**: Amazon Linux 2023
+   - **Architecture**: arm64
+
+4. Upload your `zip` file to the Lambda function.
+
 ### Logging
 
 The SDK uses tokio's [`tracing`](https://docs.rs/tracing/latest/tracing/) crate to generate logs.
@@ -121,15 +190,15 @@ The Rust SDK is currently in active development, and might break across releases
 
 The compatibility with Restate is described in the following table:
 
-| Restate Server\sdk-rust | 0.0 - 0.2 | 0.3 | 0.4 - 0.5 | 0.6              |
-|-------------------------|-----------|-----|-----------|------------------|
-| 1.0                     | ✅         | ❌   | ❌         | ❌                |
-| 1.1                     | ✅         | ✅   | ❌         | ❌                |
-| 1.2                     | ✅         | ✅   | ❌         | ❌                |
-| 1.3                     | ✅         | ✅   | ✅         | ✅ <sup>(1)</sup> |
-| 1.4                     | ✅         | ✅   | ✅         | ✅                |
+| Restate Server\sdk-rust | 0.0 - 0.2 | 0.3 | 0.4 - 0.5 | 0.6               |
+| ----------------------- | --------- | --- | --------- | ----------------- |
+| 1.0                     | ✅        | ❌  | ❌        | ❌                |
+| 1.1                     | ✅        | ✅  | ❌        | ❌                |
+| 1.2                     | ✅        | ✅  | ❌        | ❌                |
+| 1.3                     | ✅        | ✅  | ✅        | ✅ <sup>(1)</sup> |
+| 1.4                     | ✅        | ✅  | ✅        | ✅                |
 
-<sup>(1)</sup> **Note** `bind_with_options` works only from Restate 1.4 onward. 
+<sup>(1)</sup> **Note** `bind_with_options` works only from Restate 1.4 onward.
 
 ## Contributing
 

src/endpoint/mod.rs

@@ -190,7 +190,7 @@ impl Endpoint {
     pub fn handle<B: Body<Data = Bytes, Error: Into<BoxError> + Send> + Send + 'static>(
         &self,
         req: http::Request<B>,
-    ) -> Result<http::Response<ResponseBody>, Error> {
+    ) -> http::Response<ResponseBody> {
         self.handle_with_options(req, HandleOptions::default())
     }
 
@@ -201,13 +201,13 @@ impl Endpoint {
         &self,
         req: http::Request<B>,
         options: HandleOptions,
-    ) -> Result<http::Response<ResponseBody>, Error> {
+    ) -> http::Response<ResponseBody> {
         let (parts, body) = req.into_parts();
         let path = parts.uri.path();
         let headers = parts.headers;
 
         if let Err(e) = self.0.identity_verifier.verify_identity(&headers, path) {
-            return Err(ErrorInner::IdentityVerification(e).into());
+            return error_response(ErrorInner::IdentityVerification(e));
         }
 
         let parts: Vec<&str> = path.split('/').collect();
@@ -221,17 +221,17 @@ impl Endpoint {
 
         // Parse service name/handler name
         let (svc_name, handler_name) = match parts.get(parts.len() - 3..) {
-            None => return Ok(error_response(ErrorInner::BadPath(path.to_owned()))),
+            None => return error_response(ErrorInner::BadPath(path.to_owned())),
             Some(last_elements) if last_elements[0] != "invoke" => {
-                return Ok(error_response(ErrorInner::BadPath(path.to_owned())))
+                return error_response(ErrorInner::BadPath(path.to_owned()))
             }
             Some(last_elements) => (last_elements[1].to_owned(), last_elements[2].to_owned()),
         };
 
         // Prepare vm
         let vm = match CoreVM::new(headers, Default::default()) {
             Ok(vm) => vm,
-            Err(e) => return Ok(error_response(e)),
+            Err(e) => return error_response(e),
         };
         let ResponseHead {
             status_code,
@@ -241,9 +241,7 @@ impl Endpoint {
 
         // Resolve service
         if !self.0.svcs.contains_key(&svc_name) {
-            return Ok(error_response(ErrorInner::UnknownService(
-                svc_name.to_owned(),
-            )));
+            return error_response(ErrorInner::UnknownService(svc_name.to_owned()));
         }
 
         // Prepare handle_invocation future
@@ -269,7 +267,7 @@ impl Endpoint {
             invocation_response_builder =
                 invocation_response_builder.header(key.deref(), value.deref());
         }
-        Ok(invocation_response_builder
+        invocation_response_builder
             .body(
                 Either::Right(InvocationRunnerBody {
                     fut: Some(handle_invocation_fut),
@@ -278,25 +276,25 @@ impl Endpoint {
                 })
                 .into(),
             )
-            .expect("Headers should be valid"))
+            .expect("Headers should be valid")
     }
 
-    fn handle_health(&self) -> Result<http::Response<ResponseBody>, Error> {
-        Ok(simple_response(200, vec![], Bytes::default()))
+    fn handle_health(&self) -> http::Response<ResponseBody> {
+        simple_response(200, vec![], Bytes::default())
     }
 
     fn handle_discovery(
         &self,
         headers: http::HeaderMap,
         protocol_mode: ProtocolMode,
-    ) -> Result<http::Response<ResponseBody>, Error> {
+    ) -> http::Response<ResponseBody> {
         // Extract Accept header from request
         let accept_header = match headers
             .extract("accept")
             .map_err(|e| ErrorInner::Header("accept".to_owned(), Box::new(e)))
         {
             Ok(h) => h,
-            Err(e) => return Ok(error_response(e)),
+            Err(e) => return error_response(e),
         };
 
         // Negotiate discovery protocol version
@@ -310,17 +308,15 @@ impl Endpoint {
                 version = 2;
                 content_type = DISCOVERY_CONTENT_TYPE_V2;
             } else {
-                return Ok(error_response(ErrorInner::BadDiscoveryVersion(
-                    accept.to_owned(),
-                )));
+                return error_response(ErrorInner::BadDiscoveryVersion(accept.to_owned()));
             }
         }
 
         if let Err(e) = self.validate_discovery_request(version) {
-            return Ok(error_response(e));
+            return error_response(e);
         }
 
-        Ok(simple_response(
+        simple_response(
             200,
             vec![Header {
                 key: "content-type".into(),
@@ -340,7 +336,7 @@ impl Endpoint {
                 })
                 .expect("Discovery should be serializable"),
             ),
-        ))
+        )
     }
 
     fn validate_discovery_request(&self, version: usize) -> Result<(), ErrorInner> {

src/hyper.rs

@@ -6,6 +6,7 @@ use crate::endpoint::{Endpoint, HandleOptions, ProtocolMode};
 use http::{Request, Response};
 use hyper::body::Incoming;
 use hyper::service::Service;
+use std::convert::Infallible;
 use std::future::{ready, Ready};
 
 /// Wraps [`Endpoint`] to implement hyper [`Service`].
@@ -20,15 +21,15 @@ impl HyperEndpoint {
 
 impl Service<Request<Incoming>> for HyperEndpoint {
     type Response = Response<endpoint::ResponseBody>;
-    type Error = endpoint::Error;
+    type Error = Infallible;
     type Future = Ready<Result<Self::Response, Self::Error>>;
 
     fn call(&self, req: Request<Incoming>) -> Self::Future {
-        ready(self.0.handle_with_options(
+        ready(Ok(self.0.handle_with_options(
             req,
             HandleOptions {
                 protocol_mode: ProtocolMode::BidiStream,
             },
-        ))
+        )))
     }
 }