Struct LogEntry 

pub struct LogEntry {
    pub term: Term,
    pub index: Index,
    pub kind: EntryKind,
    pub command: Vec<u8>,
}

A single entry in the replicated log.

The command is opaque bytes: for a Normal entry the protocol replicates and orders it but never interprets it, and the application’s state machine decodes it on apply; for a Config entry the bytes encode the new voting membership. Each entry records the term in which the leader created it and its index in the log, which together identify it uniquely.

Examples

use raft_io::LogEntry;

let entry = LogEntry::new(2, 7, b"put k v".to_vec());
assert_eq!(entry.term, 2);
assert_eq!(entry.index, 7);
assert_eq!(entry.command, b"put k v");

Fields

term: Term

Term in which the leader created this entry.

index: Index

1-based position of this entry in the log.

kind: EntryKind

Whether this is a normal command or a configuration change.

command: Vec<u8>

Opaque bytes: an application command, or an encoded member set for a Config entry.

Implementations

impl LogEntry

pub fn new(term: Term, index: Index, command: Vec<u8>) -> Self

Creates a Normal log entry at index in term carrying command.

Examples

use raft_io::LogEntry;

let e = LogEntry::new(1, 1, vec![0xAB]);
assert_eq!(e.command, vec![0xAB]);

pub fn config(term: Term, index: Index, members: &[NodeId]) -> Self

Creates a Config log entry carrying the voting membership members.

Examples

use raft_io::LogEntry;

let e = LogEntry::config(3, 9, &[1, 2, 3]);
assert_eq!(e.members(), Some(vec![1, 2, 3]));

pub fn members(&self) -> Option<Vec<NodeId>>

Returns the voting membership a Config entry carries, or None for a Normal entry.

Examples

use raft_io::LogEntry;

assert_eq!(LogEntry::new(1, 1, vec![]).members(), None);
assert_eq!(LogEntry::config(1, 2, &[7, 8]).members(), Some(vec![7, 8]));

Trait Implementations

impl Clone for LogEntry

fn clone(&self) -> LogEntry

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for LogEntry

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deserialize for LogEntry

fn deserialize<__D: Decode + ?Sized>(__decoder: &mut __D) -> Result<Self>

Read a value of Self from the decoder, advancing its cursor.

fn deserialize_many<D>( decoder: &mut D, count: usize, ) -> Result<Vec<Self>, SerialError>

where D: Decode + ?Sized,

Read count consecutive Self values into a freshly-allocated Vec.

impl Eq for LogEntry

impl PartialEq for LogEntry

fn eq(&self, other: &LogEntry) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for LogEntry

fn serialize<__E: Encode + ?Sized>(&self, __encoder: &mut __E) -> Result<()>

Append the encoded bytes of self to encoder.

fn serialize_slice<E>( slice: &[Self], encoder: &mut E, ) -> Result<(), SerialError>

where E: Encode + ?Sized, Self: Sized,

Append the encoded bytes of every element of slice to encoder.

impl StructuralPartialEq for LogEntry