risingwave_meta/rpc/election/
dummy.rs

1// Copyright 2025 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 tokio::sync::watch::{self, Receiver, Sender};
16
17use crate::{ElectionClient, ElectionMember, MetaResult};
18
19/// A dummy implementation of [`ElectionClient`] for scenarios where only one meta node is running,
20/// typically for testing purposes such as an in-memory meta store.
21///
22/// This can be used to unify the code paths no matter there's HA or not.
23pub struct DummyElectionClient {
24    id: String,
25
26    /// A dummy watcher that never changes, indicating we are always the leader.
27    dummy_watcher: Sender<bool>,
28}
29
30impl DummyElectionClient {
31    pub fn new(id: String) -> Self {
32        Self {
33            id,
34            dummy_watcher: watch::channel(true).0,
35        }
36    }
37
38    fn self_member(&self) -> ElectionMember {
39        ElectionMember {
40            id: self.id.clone(),
41            is_leader: true,
42        }
43    }
44}
45
46#[async_trait::async_trait]
47impl ElectionClient for DummyElectionClient {
48    fn id(&self) -> MetaResult<String> {
49        Ok(self.id.clone())
50    }
51
52    async fn run_once(&self, _ttl: i64, mut stop: Receiver<()>) -> MetaResult<()> {
53        // Only exit when the stop signal is received.
54        let _ = stop.changed().await;
55        Ok(())
56    }
57
58    fn subscribe(&self) -> Receiver<bool> {
59        self.dummy_watcher.subscribe()
60    }
61
62    async fn leader(&self) -> MetaResult<Option<ElectionMember>> {
63        Ok(Some(self.self_member()))
64    }
65
66    async fn get_members(&self) -> MetaResult<Vec<ElectionMember>> {
67        Ok(vec![self.self_member()])
68    }
69
70    fn is_leader(&self) -> bool {
71        true
72    }
73}
risingwave_meta/rpc/election/dummy.rs

risingwave_meta/rpc/election/
dummy.rs
