tower_balance/p2c/
layer.rs

1use super::BalanceMake;
2use rand::{rngs::SmallRng, Rng, SeedableRng};
3use std::{fmt, marker::PhantomData};
4use tower_layer::Layer;
5
6/// Efficiently distributes requests across an arbitrary number of services
7#[derive(Clone)]
8pub struct BalanceLayer<D, Req> {
9    rng: SmallRng,
10    _marker: PhantomData<fn(D, Req)>,
11}
12
13impl<D, Req> BalanceLayer<D, Req> {
14    /// Builds a balancer using the system entropy.
15    pub fn new() -> Self {
16        Self {
17            rng: SmallRng::from_entropy(),
18            _marker: PhantomData,
19        }
20    }
21
22    /// Builds a balancer from the provided RNG.
23    ///
24    /// This may be preferrable when many balancers are initialized.
25    pub fn from_rng<R: Rng>(rng: &mut R) -> Result<Self, rand::Error> {
26        let rng = SmallRng::from_rng(rng)?;
27        Ok(Self {
28            rng,
29            _marker: PhantomData,
30        })
31    }
32}
33
34impl<S, Req> Layer<S> for BalanceLayer<S, Req> {
35    type Service = BalanceMake<S, Req>;
36
37    fn layer(&self, make_discover: S) -> Self::Service {
38        BalanceMake::new(make_discover, self.rng.clone())
39    }
40}
41
42impl<D, Req> fmt::Debug for BalanceLayer<D, Req> {
43    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
44        f.debug_struct("BalanceLayer")
45            .field("rng", &self.rng)
46            .finish()
47    }
48}
tower_balance/p2c/layer.rs

tower_balance/p2c/
layer.rs
