Struct MasterTracker 

pub struct MasterTracker { /* private fields */ }

Tracks the current known master of the replication group.

All methods are safe to call concurrently from multiple threads. Reads use a shared lock; writes use an exclusive lock.

When a PhiAccrualDetector is attached (via MasterTracker::with_phi), is_master_alive uses the continuous φ suspicion level instead of the binary heartbeat timeout. This adapts automatically to network jitter.

Implementations

impl MasterTracker

pub fn new(heartbeat_timeout: Duration) -> Self

Create a new tracker with the given heartbeat timeout.

Uses binary heartbeat timeout for liveness detection. Call with_phi to switch to phi accrual detection.

pub fn with_phi(self, detector: PhiAccrualDetector) -> Self

Attach a phi accrual failure detector.

When attached, is_master_alive returns phi_detector.is_available() instead of the binary timeout check.

pub fn set_master(&self, name: &str, term: u64)

Set the current master and its term unconditionally.

Also records a heartbeat at the current time.

pub fn clear_master(&self)

Clear the current master.

After this call, get_master returns None.

pub fn get_master(&self) -> Option<String>

Returns the name of the current master, if known.

pub fn get_term(&self) -> u64

Returns the term of the current master.

pub fn record_heartbeat(&self)

Record a heartbeat from the master at the current time.

pub fn is_master_alive(&self) -> bool

Returns true if a master is set and it is still considered alive.

When a phi detector is configured, uses the continuous suspicion level (phi.is_available()). Otherwise falls back to binary heartbeat timeout (elapsed < heartbeat_timeout).

pub fn phi(&self) -> Option<f64>

Returns the current phi suspicion value, or None if no phi detector is configured.

pub fn time_since_heartbeat(&self) -> Option<Duration>

Returns the duration since the last heartbeat, or None if no heartbeat has been recorded.

pub fn update_master(&self, name: &str, term: u64) -> bool

Update the master only if term is greater than or equal to the current term.

This ensures that stale election results (from older terms) cannot overwrite a more recent master.

Returns true if the master was updated, false if the update was rejected due to a stale term.

pub fn heartbeat_timeout(&self) -> Duration

Returns the configured heartbeat timeout.