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::Arc;
16use std::sync::atomic::{AtomicU64, Ordering};
17use std::task::{Context, Poll};
18
19use either::Either;
20use futures::Future;
21use tonic::body::Body;
22use tower::{Layer, Service};
23
24/// Manages the await-trees of `gRPC` requests that are currently served by a node.
25pub type AwaitTreeRegistryRef = await_tree::Registry;
26
27/// Await-tree key type for `gRPC` calls.
28#[derive(Debug, Clone, PartialEq, Eq, Hash)]
29pub struct GrpcCall {
30    pub desc: String,
31}
32
33#[derive(Clone)]
34pub struct AwaitTreeMiddlewareLayer {
35    registry: Option<AwaitTreeRegistryRef>,
36}
37
38impl AwaitTreeMiddlewareLayer {
39    pub fn new(registry: AwaitTreeRegistryRef) -> Self {
40        Self {
41            registry: Some(registry),
42        }
43    }
44
45    pub fn new_optional(registry: Option<AwaitTreeRegistryRef>) -> Self {
46        Self { registry }
47    }
48}
49
50impl<S> Layer<S> for AwaitTreeMiddlewareLayer {
51    type Service = AwaitTreeMiddleware<S>;
52
53    fn layer(&self, service: S) -> Self::Service {
54        AwaitTreeMiddleware {
55            inner: service,
56            registry: self.registry.clone(),
57            next_id: Default::default(),
58        }
59    }
60}
61
62#[derive(Clone)]
63pub struct AwaitTreeMiddleware<S> {
64    inner: S,
65    registry: Option<AwaitTreeRegistryRef>,
66    next_id: Arc<AtomicU64>,
67}
68
69impl<S> Service<http::Request<Body>> for AwaitTreeMiddleware<S>
70where
71    S: Service<http::Request<Body>> + Clone,
72{
73    type Error = S::Error;
74    type Response = S::Response;
75
76    type Future = impl Future<Output = Result<Self::Response, Self::Error>>;
77
78    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
79        self.inner.poll_ready(cx)
80    }
81
82    fn call(&mut self, req: http::Request<Body>) -> Self::Future {
83        let Some(registry) = self.registry.clone() else {
84            return Either::Left(self.inner.call(req));
85        };
86
87        // This is necessary because tonic internally uses `tower::buffer::Buffer`.
88        // See https://github.com/tower-rs/tower/issues/547#issuecomment-767629149
89        // for details on why this is necessary
90        let clone = self.inner.clone();
91        let mut inner = std::mem::replace(&mut self.inner, clone);
92
93        let id = self.next_id.fetch_add(1, Ordering::SeqCst);
94        let desc = if let Some(authority) = req.uri().authority() {
95            format!("{authority} - {id}")
96        } else {
97            format!("?? - {id}")
98        };
99        let key = GrpcCall { desc };
100
101        Either::Right(async move {
102            let root = registry.register(key, req.uri().path());
103
104            root.instrument(inner.call(req)).await
105        })
106    }
107}
108
109#[cfg(not(madsim))]
110impl<S: tonic::server::NamedService> tonic::server::NamedService for AwaitTreeMiddleware<S> {
111    const NAME: &'static str = S::NAME;
112}
risingwave_common_service/await_tree_middleware.rs

risingwave_common_service/
await_tree_middleware.rs
