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// SPDX-License-Identifier: Apache-2.0
//! The request and answer rows of `MetaOp::HomeVersions`.
/// One vShard home whose current version a core reports.
#[derive(
Debug,
Clone,
PartialEq,
Eq,
PartialOrd,
Ord,
Hash,
serde::Serialize,
serde::Deserialize,
zerompk::ToMessagePack,
zerompk::FromMessagePack,
)]
pub struct HomeVersionProbe {
/// The vShard the home read observed.
pub vshard: u32,
/// The database-qualified collection the read scoped, or `None` when the
/// read walked every collection.
pub collection: Option<String>,
}
/// A node's answer for one [`HomeVersionProbe`].
#[derive(
Debug,
Clone,
PartialEq,
Eq,
serde::Serialize,
serde::Deserialize,
zerompk::ToMessagePack,
zerompk::FromMessagePack,
)]
pub struct HomeVersion {
pub probe: HomeVersionProbe,
pub answer: HomeAnswer,
}
/// What a node answers for one home.
#[derive(
Debug,
Clone,
Copy,
PartialEq,
Eq,
serde::Serialize,
serde::Deserialize,
zerompk::ToMessagePack,
zerompk::FromMessagePack,
)]
pub enum HomeAnswer {
/// The collection's write floor on the probe's vShard, or that vShard's
/// latest version for a probe with no collection.
Version(nodedb_types::WriteVersion),
/// The node does not hold the leader lease of the probe's group, so it
/// cannot answer. `leader_node` is the leader its routing table names at
/// `leader_term`, `0` when it names none.
NotLeader { leader_node: u64, leader_term: u64 },
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn answers_round_trip_through_msgpack() {
let answers = vec![
HomeVersion {
probe: HomeVersionProbe {
vshard: 7,
collection: Some("db1.edges".into()),
},
answer: HomeAnswer::Version(nodedb_types::WriteVersion::logged(3, 42)),
},
HomeVersion {
probe: HomeVersionProbe {
vshard: 9,
collection: None,
},
answer: HomeAnswer::NotLeader {
leader_node: 2,
leader_term: 7,
},
},
];
let bytes = zerompk::to_msgpack_vec(&answers).expect("encode");
let decoded: Vec<HomeVersion> = zerompk::from_msgpack(&bytes).expect("decode");
assert_eq!(decoded, answers);
}
}