batch_aint_one/
processor.rs

1use std::{
2    fmt::{Debug, Display},
3    future::Future,
4    hash::Hash,
5};
6
7/// Process a batch of inputs for a given key.
8///
9/// Should be cheap to clone.
10pub trait Processor: 'static + Send + Clone {
11    /// The key used to group inputs.
12    type Key: 'static + Debug + Eq + Hash + Clone + Send + Sync;
13    /// The input type for each item.
14    type Input: Send;
15    /// The output type for each item.
16    type Output: Send;
17    /// The error type that can be returned when processing a batch.
18    type Error: Send + Clone + Display + Debug;
19    /// The resources that will be acquired before processing each batch, and can be used during
20    /// processing.
21    type Resources: Send;
22
23    /// Acquire resources to be used for processing the next batch with the given key.
24    ///
25    /// This method is called before processing each batch.
26    ///
27    /// For the `Immediate` and `Balanced` batching policies, resources can be acquired before the
28    /// batch is processed, and the batch will keep accumulating items until the resources are
29    /// acquired.
30    ///
31    /// Can be used to e.g. acquire a database connection from a pool.
32    fn acquire_resources(
33        &self,
34        key: Self::Key,
35    ) -> impl Future<Output = Result<Self::Resources, Self::Error>> + Send;
36
37    /// Process the batch.
38    ///
39    /// Must return exactly one output per input, in the same order as the inputs in the given
40    /// iterator. If the number of outputs is wrong, every item in the batch receives a
41    /// `BatchError::ProcessorInvariantViolation` error.
42    fn process(
43        &self,
44        key: Self::Key,
45        inputs: impl Iterator<Item = Self::Input> + Send,
46        resources: Self::Resources,
47    ) -> impl Future<Output = Result<Vec<Self::Output>, Self::Error>> + Send;
48}
batch_aint_one/processor.rs

batch_aint_one/
processor.rs
