risingwave_common_service/
await_tree_middleware.rs

1// Copyright 2026 RisingWave Labs
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15use std::sync::atomic::{AtomicU64, Ordering};
16use std::task::{Context, Poll};
17
18use either::Either;
19use futures::Future;
20use tonic::body::Body;
21use tower::{Layer, Service};
22
23/// Manages the await-trees of `gRPC` requests that are currently served by a node.
24pub type AwaitTreeRegistryRef = await_tree::Registry;
25
26static NEXT_GRPC_CALL_ID: AtomicU64 = AtomicU64::new(0);
27
28/// Await-tree key type for `gRPC` calls.
29#[derive(Debug, Clone, PartialEq, Eq, Hash)]
30pub struct GrpcCall {
31    pub desc: String,
32}
33
34impl GrpcCall {
35    /// Creates a key with an ID shared by all middleware layers and registries in this process.
36    pub fn new(desc: impl Into<String>) -> Self {
37        let id = NEXT_GRPC_CALL_ID.fetch_add(1, Ordering::Relaxed);
38        Self {
39            desc: format!("{} - {id}", desc.into()),
40        }
41    }
42}
43
44#[derive(Clone)]
45pub struct AwaitTreeMiddlewareLayer {
46    registry: Option<AwaitTreeRegistryRef>,
47}
48
49impl AwaitTreeMiddlewareLayer {
50    pub fn new(registry: AwaitTreeRegistryRef) -> Self {
51        Self {
52            registry: Some(registry),
53        }
54    }
55
56    pub fn new_optional(registry: Option<AwaitTreeRegistryRef>) -> Self {
57        Self { registry }
58    }
59}
60
61impl<S> Layer<S> for AwaitTreeMiddlewareLayer {
62    type Service = AwaitTreeMiddleware<S>;
63
64    fn layer(&self, service: S) -> Self::Service {
65        AwaitTreeMiddleware {
66            inner: service,
67            registry: self.registry.clone(),
68        }
69    }
70}
71
72#[derive(Clone)]
73pub struct AwaitTreeMiddleware<S> {
74    inner: S,
75    registry: Option<AwaitTreeRegistryRef>,
76}
77
78impl<S> Service<http::Request<Body>> for AwaitTreeMiddleware<S>
79where
80    S: Service<http::Request<Body>> + Clone,
81{
82    type Error = S::Error;
83    type Response = S::Response;
84
85    type Future = impl Future<Output = Result<Self::Response, Self::Error>>;
86
87    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
88        self.inner.poll_ready(cx)
89    }
90
91    fn call(&mut self, req: http::Request<Body>) -> Self::Future {
92        let Some(registry) = self.registry.clone() else {
93            return Either::Left(self.inner.call(req));
94        };
95
96        // This is necessary because tonic internally uses `tower::buffer::Buffer`.
97        // See https://github.com/tower-rs/tower/issues/547#issuecomment-767629149
98        // for details on why this is necessary
99        let clone = self.inner.clone();
100        let mut inner = std::mem::replace(&mut self.inner, clone);
101
102        let desc = req
103            .uri()
104            .authority()
105            .map_or("??", |authority| authority.as_str());
106        let key = GrpcCall::new(desc);
107
108        Either::Right(async move {
109            let root = registry.register(key, req.uri().path());
110
111            root.instrument(inner.call(req)).await
112        })
113    }
114}
115
116#[cfg(not(madsim))]
117impl<S: tonic::server::NamedService> tonic::server::NamedService for AwaitTreeMiddleware<S> {
118    const NAME: &'static str = S::NAME;
119}
risingwave_common_service/await_tree_middleware.rs

risingwave_common_service/
await_tree_middleware.rs
