Add tower example

hit-box · Apr 10, 2022 · c990d07 · c990d07
1 parent 7f6d37c
commit c990d07
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diff --git a/Cargo.toml b/Cargo.toml
@@ -7,5 +7,6 @@ members = [
     "hitbox-backend",
     "hitbox-derive",
     "hitbox-redis",
+    "hitbox-tower",
     "examples",
 ]
diff --git a/examples/Cargo.toml b/examples/Cargo.toml
@@ -24,3 +24,9 @@ actix_derive = "0.6"
 actix-web = "3"
 tracing = "0.1"
 tracing-subscriber = "0.2"
+
+hyper = { version = "0.14", features = ["full"] }
+tokio = { version = "1", features = ["full"] }
+tower = { version = "0.4", features = ["full"] }
+tower-http = { version = "0.2", features = ["full"] }
+http = "0.2"
diff --git a/examples/examples/tower.rs b/examples/examples/tower.rs
@@ -0,0 +1,23 @@
+use std::{convert::Infallible, net::SocketAddr};
+use hyper::{Body, Server};
+
+use tower::make::Shared;
+use http::{Request, Response};
+
+async fn handle(_: Request<Body>) -> Result<Response<Body>, Infallible> {
+    Ok(Response::new("Hello, World!".into()))
+}
+
+#[tokio::main]
+async fn main() {
+    let service = tower::ServiceBuilder::new()
+        .layer(tower_http::trace::TraceLayer::new_for_http())
+        .service_fn(handle);
+
+    let addr = SocketAddr::from(([127, 0, 0, 1], 3000));
+    Server::bind(&addr)
+        .serve(Shared::new(service))
+        .await
+        .expect("server error");
+}
+
diff --git a/hitbox-tower/Cargo.toml b/hitbox-tower/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+edition = "2021"
+name = "hitbox-tower"
+version = "0.1.0"
+
+[dependencies]
+tower = "0.4"
+
+
diff --git a/hitbox-tower/src/lib.rs b/hitbox-tower/src/lib.rs
@@ -0,0 +1,8 @@
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {
+        let result = 2 + 2;
+        assert_eq!(result, 4);
+    }
+}
diff --git a/hitbox-tower/src/runtime.rs b/hitbox-tower/src/runtime.rs
@@ -0,0 +1,77 @@
+use std::{future::Future, marker::PhantomData};
+
+use async_trait::async_trait;
+
+use hitbox::{
+    runtime::{AdapterResult, RuntimeAdapter},
+    CacheError, CacheState, CacheableResponse, Cacheable,
+};
+use hitbox_backend::CacheBackend;
+use serde::de::DeserializeOwned;
+
+pub struct TowerAdapter<'b, Request, Response, Service, B> 
+where
+    Request: Cacheable,
+{
+    _response: PhantomData<Response>,
+    backend: &'b B,
+    upstream: Service,
+    request: Option<Request>,
+    cache_key: String,
+    cache_ttl: u32,
+    cache_stale_ttl: u32,
+}
+
+impl<'b, Request, Response, Service, B> FutureAdapter<'b, Request, Response, Service, B>
+where
+    Request: Cacheable,
+{
+    pub fn new(upstream: U, request: Request, backend: &'b B) -> Result<Self, CacheError> {
+        Ok(Self {
+            cache_key: request.cache_key()?,
+            cache_ttl: request.cache_ttl(),
+            cache_stale_ttl: request.cache_stale_ttl(),
+            request: Some(request),
+            upstream,
+            backend,
+            _response: PhantomData::default(),
+        })
+    }
+}
+
+#[async_trait]
+impl<Request, Response, Service, B, 'b> crate::runtime::RuntimeAdapter for FutureAdapter<'b, Request, Response, U, B>
+where
+    Request: Cacheable + Send + Sync,
+{
+    type UpstreamResult = Response;
+    async fn update_cache<'a>(
+        &self,
+        cached_value: &'a hitbox_backend::CachedValue<Self::UpstreamResult>,
+    ) -> crate::runtime::AdapterResult<()> {
+        Ok(self
+            .backend
+            .set(self.cache_key.clone(), cached_value, Some(self.cache_ttl))
+            .await?)
+    }
+
+    async fn poll_cache(&self) -> crate::runtime::AdapterResult<CacheState<Self::UpstreamResult>> {
+        Ok(self.backend.get(self.cache_key.clone()).await?.into())
+    }
+
+    async fn poll_upstream(&mut self) -> crate::runtime::AdapterResult<Self::UpstreamResult> {
+        let request = self.request.take();
+        let request = request.ok_or_else(|| {
+            CacheError::CacheKeyGenerationError("Request already sent to upstream".to_owned())
+        })?;
+        Ok(self.upstream.call(request).await)
+    }
+
+    fn eviction_settings(&self) -> hitbox_backend::EvictionPolicy {
+        let ttl_settings = hitbox_backend::TtlSettings {
+            ttl: self.cache_ttl,
+            stale_ttl: self.cache_stale_ttl,
+        };
+        hitbox_backend::EvictionPolicy::Ttl(ttl_settings)
+    }
+}