memberlist_core/delegate/
node.rs

1use std::{borrow::Cow, future::Future};
2
3use crate::proto::Meta;
4use bytes::Bytes;
5
6/// Used to manage node related events.
7#[auto_impl::auto_impl(Box, Arc)]
8pub trait NodeDelegate: Send + Sync + 'static {
9  /// Used to retrieve meta-data about the current node
10  /// when broadcasting an alive message. It's length is limited to
11  /// the given byte size. This metadata is available in the NodeState structure.
12  fn node_meta(&self, limit: usize) -> impl Future<Output = Meta> + Send {
13    let _ = limit;
14    async move { Meta::empty() }
15  }
16
17  /// Called when a user-data message is received.
18  /// Care should be taken that this method does not block, since doing
19  /// so would block the entire UDP packet receive loop. Additionally, the byte
20  /// slice may be modified after the call returns, so it should be copied if needed
21  fn notify_message(&self, msg: Cow<'_, [u8]>) -> impl Future<Output = ()> + Send {
22    async move {
23      let _ = msg;
24    }
25  }
26
27  /// Called when user data messages can be broadcast.
28  /// It can return a list of buffers to send. Each buffer should assume an
29  /// overhead as provided with a limit on the total byte size allowed.
30  /// The total byte size of the resulting data to send must not exceed
31  /// the limit. Care should be taken that this method does not block,
32  /// since doing so would block the entire UDP packet receive loop.
33  ///
34  /// The `encoded_len` function accepts a bytes, and will return
35  /// the same bytes back and the encoded length of the message.
36  fn broadcast_messages<F>(
37    &self,
38    limit: usize,
39    encoded_len: F,
40  ) -> impl Future<Output = impl Iterator<Item = Bytes> + Send> + Send
41  where
42    F: Fn(Bytes) -> (usize, Bytes) + Send + Sync + 'static,
43  {
44    let _ = limit;
45    let _ = encoded_len;
46    async move { std::iter::empty() }
47  }
48
49  /// Used for a TCP Push/Pull. This is sent to
50  /// the remote side in addition to the membership information. Any
51  /// data can be sent here. See `merge_remote_state` as well. The `join`
52  /// boolean indicates this is for a join instead of a push/pull.
53  fn local_state(&self, join: bool) -> impl Future<Output = Bytes> + Send {
54    let _ = join;
55    async move { Bytes::new() }
56  }
57
58  /// Invoked after a TCP Push/Pull. This is the
59  /// state received from the remote side and is the result of the
60  /// remote side's `local_state` call. The 'join'
61  /// boolean indicates this is for a join instead of a push/pull.
62  fn merge_remote_state(&self, buf: &[u8], join: bool) -> impl Future<Output = ()> + Send {
63    let _ = buf;
64    let _ = join;
65    async move {}
66  }
67}
memberlist_core/delegate/node.rs

memberlist_core/delegate/
node.rs
