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authorAlex Auvolat <alex@adnab.me>2024-02-13 12:55:41 +0100
committerAlex Auvolat <alex@adnab.me>2024-02-15 12:15:07 +0100
commit5ea24254a91c3794ceb69e68c940b13f5447f40c (patch)
treedc30460edeb757699fc7057a7fed640c69dfb79d /src/net/endpoint.rs
parenta2ab275da80159ea2f0606d129790d79d43b4e24 (diff)
downloadgarage-5ea24254a91c3794ceb69e68c940b13f5447f40c.tar.gz
garage-5ea24254a91c3794ceb69e68c940b13f5447f40c.zip
[import-netapp] import Netapp code into Garage codebase
Diffstat (limited to 'src/net/endpoint.rs')
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diff --git a/src/net/endpoint.rs b/src/net/endpoint.rs
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+use std::marker::PhantomData;
+use std::sync::Arc;
+
+use arc_swap::ArcSwapOption;
+use async_trait::async_trait;
+
+use crate::error::Error;
+use crate::message::*;
+use crate::netapp::*;
+
+/// This trait should be implemented by an object of your application
+/// that can handle a message of type `M`, if it wishes to handle
+/// streams attached to the request and/or to send back streams
+/// attached to the response..
+///
+/// The handler object should be in an Arc, see `Endpoint::set_handler`
+#[async_trait]
+pub trait StreamingEndpointHandler<M>: Send + Sync
+where
+ M: Message,
+{
+ async fn handle(self: &Arc<Self>, m: Req<M>, from: NodeID) -> Resp<M>;
+}
+
+/// If one simply wants to use an endpoint in a client fashion,
+/// without locally serving requests to that endpoint,
+/// use the unit type `()` as the handler type:
+/// it will panic if it is ever made to handle request.
+#[async_trait]
+impl<M: Message> EndpointHandler<M> for () {
+ async fn handle(self: &Arc<()>, _m: &M, _from: NodeID) -> M::Response {
+ panic!("This endpoint should not have a local handler.");
+ }
+}
+
+// ----
+
+/// This trait should be implemented by an object of your application
+/// that can handle a message of type `M`, in the cases where it doesn't
+/// care about attached stream in the request nor in the response.
+#[async_trait]
+pub trait EndpointHandler<M>: Send + Sync
+where
+ M: Message,
+{
+ async fn handle(self: &Arc<Self>, m: &M, from: NodeID) -> M::Response;
+}
+
+#[async_trait]
+impl<T, M> StreamingEndpointHandler<M> for T
+where
+ T: EndpointHandler<M>,
+ M: Message,
+{
+ async fn handle(self: &Arc<Self>, mut m: Req<M>, from: NodeID) -> Resp<M> {
+ // Immediately drop stream to ignore all data that comes in,
+ // instead of buffering it indefinitely
+ drop(m.take_stream());
+ Resp::new(EndpointHandler::handle(self, m.msg(), from).await)
+ }
+}
+
+// ----
+
+/// This struct represents an endpoint for message of type `M`.
+///
+/// Creating a new endpoint is done by calling `NetApp::endpoint`.
+/// An endpoint is identified primarily by its path, which is specified
+/// at creation time.
+///
+/// An `Endpoint` is used both to send requests to remote nodes,
+/// and to specify the handler for such requests on the local node.
+/// The type `H` represents the type of the handler object for
+/// endpoint messages (see `StreamingEndpointHandler`).
+pub struct Endpoint<M, H>
+where
+ M: Message,
+ H: StreamingEndpointHandler<M>,
+{
+ _phantom: PhantomData<M>,
+ netapp: Arc<NetApp>,
+ path: String,
+ handler: ArcSwapOption<H>,
+}
+
+impl<M, H> Endpoint<M, H>
+where
+ M: Message,
+ H: StreamingEndpointHandler<M>,
+{
+ pub(crate) fn new(netapp: Arc<NetApp>, path: String) -> Self {
+ Self {
+ _phantom: PhantomData::default(),
+ netapp,
+ path,
+ handler: ArcSwapOption::from(None),
+ }
+ }
+
+ /// Get the path of this endpoint
+ pub fn path(&self) -> &str {
+ &self.path
+ }
+
+ /// Set the object that is responsible of handling requests to
+ /// this endpoint on the local node.
+ pub fn set_handler(&self, h: Arc<H>) {
+ self.handler.swap(Some(h));
+ }
+
+ /// Call this endpoint on a remote node (or on the local node,
+ /// for that matter). This function invokes the full version that
+ /// allows to attach a stream to the request and to
+ /// receive such a stream attached to the response.
+ pub async fn call_streaming<T>(
+ &self,
+ target: &NodeID,
+ req: T,
+ prio: RequestPriority,
+ ) -> Result<Resp<M>, Error>
+ where
+ T: IntoReq<M>,
+ {
+ if *target == self.netapp.id {
+ match self.handler.load_full() {
+ None => Err(Error::NoHandler),
+ Some(h) => Ok(h.handle(req.into_req_local(), self.netapp.id).await),
+ }
+ } else {
+ let conn = self
+ .netapp
+ .client_conns
+ .read()
+ .unwrap()
+ .get(target)
+ .cloned();
+ match conn {
+ None => Err(Error::Message(format!(
+ "Not connected: {}",
+ hex::encode(&target[..8])
+ ))),
+ Some(c) => c.call(req.into_req()?, self.path.as_str(), prio).await,
+ }
+ }
+ }
+
+ /// Call this endpoint on a remote node. This function is the simplified
+ /// version that doesn't allow to have streams attached to the request
+ /// or the response; see `call_streaming` for the full version.
+ pub async fn call(
+ &self,
+ target: &NodeID,
+ req: M,
+ prio: RequestPriority,
+ ) -> Result<<M as Message>::Response, Error> {
+ Ok(self.call_streaming(target, req, prio).await?.into_msg())
+ }
+}
+
+// ---- Internal stuff ----
+
+pub(crate) type DynEndpoint = Box<dyn GenericEndpoint + Send + Sync>;
+
+#[async_trait]
+pub(crate) trait GenericEndpoint {
+ async fn handle(&self, req_enc: ReqEnc, from: NodeID) -> Result<RespEnc, Error>;
+ fn drop_handler(&self);
+ fn clone_endpoint(&self) -> DynEndpoint;
+}
+
+#[derive(Clone)]
+pub(crate) struct EndpointArc<M, H>(pub(crate) Arc<Endpoint<M, H>>)
+where
+ M: Message,
+ H: StreamingEndpointHandler<M>;
+
+#[async_trait]
+impl<M, H> GenericEndpoint for EndpointArc<M, H>
+where
+ M: Message,
+ H: StreamingEndpointHandler<M> + 'static,
+{
+ async fn handle(&self, req_enc: ReqEnc, from: NodeID) -> Result<RespEnc, Error> {
+ match self.0.handler.load_full() {
+ None => Err(Error::NoHandler),
+ Some(h) => {
+ let req = Req::from_enc(req_enc)?;
+ let res = h.handle(req, from).await;
+ Ok(res.into_enc()?)
+ }
+ }
+ }
+
+ fn drop_handler(&self) {
+ self.0.handler.swap(None);
+ }
+
+ fn clone_endpoint(&self) -> DynEndpoint {
+ Box::new(Self(self.0.clone()))
+ }
+}