/
registry.rs
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/
registry.rs
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// Copyright 2023 RisingWave Labs
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
use std::borrow::Borrow;
use std::collections::HashMap;
use std::future::Future;
use std::hash::Hash;
use std::sync::{Arc, Weak};
use derive_builder::Builder;
use crate::context::{Tree, TreeContext, CONTEXT};
use crate::Span;
/// Configuration for an await-tree registry, which affects the behavior of all await-trees in the
/// registry.
#[derive(Debug, Clone, Builder)]
#[builder(default)]
pub struct Config {
/// Whether to include the **verbose** span in the await-tree.
verbose: bool,
}
#[allow(clippy::derivable_impls)]
impl Default for Config {
fn default() -> Self {
Self { verbose: false }
}
}
/// The root of an await-tree.
pub struct TreeRoot {
context: Arc<TreeContext>,
}
impl TreeRoot {
/// Instrument the given future with the context of this tree root.
pub async fn instrument<F: Future>(self, future: F) -> F::Output {
CONTEXT.scope(self.context, future).await
}
}
/// The registry of multiple await-trees.
#[derive(Debug)]
pub struct Registry<K> {
contexts: HashMap<K, Weak<TreeContext>>,
config: Config,
}
impl<K> Registry<K> {
/// Create a new registry with given `config`.
pub fn new(config: Config) -> Self {
Self {
contexts: HashMap::new(),
config,
}
}
}
impl<K> Registry<K>
where
K: std::hash::Hash + Eq + std::fmt::Debug,
{
/// Register with given key. Returns a [`TreeRoot`] that can be used to instrument a future.
///
/// If the key already exists, a new [`TreeRoot`] is returned and the reference to the old
/// [`TreeRoot`] is dropped.
pub fn register(&mut self, key: K, root_span: impl Into<Span>) -> TreeRoot {
// TODO: make this more efficient
self.contexts.retain(|_, v| v.upgrade().is_some());
let context = Arc::new(TreeContext::new(root_span.into(), self.config.verbose));
let weak = Arc::downgrade(&context);
self.contexts.insert(key, weak);
TreeRoot { context }
}
/// Iterate over the clones of all registered await-trees.
pub fn iter(&self) -> impl Iterator<Item = (&K, Tree)> {
self.contexts
.iter()
.filter_map(|(k, v)| v.upgrade().map(|v| (k, v.tree().clone())))
}
/// Get a clone of the await-tree with given key.
///
/// Returns `None` if the key does not exist or the tree root has been dropped.
pub fn get<Q: ?Sized>(&self, k: &Q) -> Option<Tree>
where
K: Borrow<Q>,
Q: Hash + Eq,
{
self.contexts
.get(k)
.and_then(|v| v.upgrade())
.map(|v| v.tree().clone())
}
/// Remove all the registered await-trees.
pub fn clear(&mut self) {
self.contexts.clear();
}
}