risingwave_meta/barrier/
trace.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 risingwave_common::util::epoch::Epoch;
16
17/// A wrapper of [`Epoch`] with tracing span, used for issuing epoch-based tracing from the barrier
18/// manager on the meta service. This structure is free to clone, which'll extend the lifetime of
19/// the underlying span.
20///
21/// - A new [`TracedEpoch`] is created when the barrier manager is going to inject a new barrier.
22///   The span will be created automatically and the start time is recorded.
23/// - Then, the previous and the current [`TracedEpoch`]s are stored in the command context.
24/// - When the barrier is successfully collected and committed, the command context will be dropped,
25///   then the previous span will be automatically closed.
26#[derive(Debug, Clone)]
27pub struct TracedEpoch {
28    epoch: Epoch,
29    span: tracing::Span,
30}
31
32impl TracedEpoch {
33    /// Create a new [`TracedEpoch`] with the given `epoch`.
34    pub fn new(epoch: Epoch) -> Self {
35        // The span created on the meta service is always a root span for epoch-level tracing.
36        let span = tracing::info_span!(
37            parent: None,
38            "epoch",
39            "otel.name" = format!("Epoch {}", epoch.0),
40            epoch = epoch.0
41        );
42
43        Self { epoch, span }
44    }
45
46    /// Create a new [`TracedEpoch`] with the next epoch.
47    pub fn next(&self) -> Self {
48        Self::new(self.epoch.next())
49    }
50
51    /// Retrieve the epoch value.
52    pub fn value(&self) -> Epoch {
53        self.epoch
54    }
55
56    /// Retrieve the tracing span.
57    pub fn span(&self) -> &tracing::Span {
58        &self.span
59    }
60}
risingwave_meta/barrier/trace.rs

risingwave_meta/barrier/
trace.rs
