Handle learner promotion after state catch-up validation.
(
node_id: u64,
topology: &mut ClusterTopology,
log_lag: u64,
max_lag: u64,
)
| 102 | |
| 103 | /// Handle learner promotion after state catch-up validation. |
| 104 | pub fn handle_learner_promotion( |
| 105 | node_id: u64, |
| 106 | topology: &mut ClusterTopology, |
| 107 | log_lag: u64, |
| 108 | max_lag: u64, |
| 109 | ) -> Result<MetadataEntry> { |
| 110 | let node = topology.get_node(node_id).ok_or(ClusterError::Transport { |
| 111 | detail: format!("node {node_id} not found"), |
| 112 | })?; |
| 113 | |
| 114 | if node.state != NodeState::Learner { |
| 115 | return Err(ClusterError::Transport { |
| 116 | detail: format!("node {node_id} is not a learner (state: {:?})", node.state), |
| 117 | }); |
| 118 | } |
| 119 | |
| 120 | if log_lag > max_lag { |
| 121 | return Err(ClusterError::Transport { |
| 122 | detail: format!("node {node_id} not caught up: lag={log_lag}, max={max_lag}"), |
| 123 | }); |
| 124 | } |
| 125 | |
| 126 | topology.promote_to_voter(node_id); |
| 127 | info!(node_id, log_lag, "learner promoted to voter"); |
| 128 | |
| 129 | Ok(MetadataEntry::TopologyChange( |
| 130 | TopologyChange::PromoteToVoter { node_id }, |
| 131 | )) |
| 132 | } |
| 133 | |
| 134 | #[cfg(test)] |
| 135 | mod tests { |