Crate openraft

Openraft

API status

Openraft API is currently unstable. Incompatibilities may arise in upgrades prior to 1.0.0. Refer to our Change-Log for details. Upgrade Guides explains how to upgrade.

Each commit message begins with a keyword indicating the type of change:

• DataChange: Changes to on-disk data types, possibly requiring manual upgrade.
• Change: Introduces incompatible API changes.
• Feature: Adds compatible, non-breaking new features.
• Fix: Addresses bug fixes.

Openraft Document

If you’re starting to build an application with Openraft, check out

• getting_started.
• faq,

To maintain an Openraft cluster, e.g., add or remove nodes, refer to

• cluster_control :
  • cluster_formation describes how to form a cluster;
  • dynamic membership describes how to add or remove nodes without downtime;
  • node lifecycle describes the transition of a node’s state;

When upgrading an Openraft application, consult:

• upgrade_guide :
  • v0.6-to-v0.7;
  • v0.7-to-v0.8;
  • v0.8.3-to-v0.8.4;
  • v0.8-to-v0.9;

To learn about the data structures used in Openraft and the commit protocol, see

• feature_flags;
• data :
  • Vote is the core in a distributed system;
  • Log pointers shows how Openraft tracks entries in the log;
  • Leader lease explains leader lease for a Leader and a Follower;
  • Extended membership explains how members are organized in Openraft;
  • Effective membership explains when membership config takes effect;
• components explains the components in Openraft;
  • RaftStateMachine is the core API for managing the state machine and snapshot functionalities;
• protocol :
  • replication;
    • leader_lease;
    • log_replication;
    • snapshot_replication;

Contributors who want to understand the internals of Openraft can find relevant information in

• internal :
  • Architecture shows the overall architecture of Openraft;
  • Threading describes the threading model of Openraft;

Finally, the archived and discarded documents:

• obsolete describes obsolete design documents and why they are discarded;
  • blank-log-heartbeeat;
  • fast-commit;

Re-exports

pub extern crate openraft_macros;

pub use crate::async_runtime::AsyncRuntime;

pub use crate::async_runtime::TokioRuntime;

pub use crate::entry::Entry;

pub use crate::entry::EntryPayload;

pub use crate::instant::Instant;

pub use crate::instant::TokioInstant;

pub use crate::log_id::LogId;

pub use crate::log_id::LogIdOptionExt;

pub use crate::log_id::LogIndexOptionExt;

pub use crate::log_id::RaftLogId;

pub use crate::metrics::RaftMetrics;

pub use crate::network::RPCTypes;

pub use crate::network::RaftNetwork;

pub use crate::network::RaftNetworkFactory;

pub use crate::raft::Raft;

pub use crate::storage::LogState;

pub use crate::storage::RaftLogReader;

pub use crate::storage::RaftSnapshotBuilder;

pub use crate::storage::Snapshot;

pub use crate::storage::SnapshotMeta;

pub use crate::storage::StorageHelper;

pub use crate::type_config::RaftTypeConfig;

pub use anyerror;

Modules

async_runtime

async runtime interface.

compat

This mod is a upgrade helper that provides functionalities for a newer openraft application to read data written by an older application.

docs

Openraft Document

entry

The default log entry type that implements RaftEntry.

error

Error types exposed by this crate.

impls

Collection of implementations of usually used traits defined by Openraft

instant

A trait for time instants.

log_id

This mod defines the identity of a raft log and provides supporting utilities to work with log id related types.

metrics

Raft metrics for observability.

network

The Raft network interface.

raft

Public Raft interface and data types.

storage

The Raft storage interface and data types.

testing

Testing utilities for OpenRaft.

type_config

Define the configuration of types used by the Raft, such as NodeId, log Entry, etc.

Macros

declare_raft_types

Define types for a Raft type configuration.

Structs

AnyError

AnyError is a serializable wrapper Error.

BasicNode

An implementation of trait Node that contains minimal node information.

Config

The runtime configuration for a Raft node.

DefensiveError

An error that occurs when the RaftStore impl runs defensive check of input or output. E.g. re-applying an log entry is a violation that may be a potential bug.

EffectiveMembership

The currently active membership config.

EmptyNode

EmptyNode is an implementation of trait Node that contains nothing.

LeaderId

LeaderId is identifier of a leader.

Membership

The membership configuration of the cluster.

MembershipState

The state of membership configs a raft node needs to know.

RaftState

A struct used to represent the raft state which a Raft node needs.

SnapshotSegmentId

The identity of a segment of a snapshot.

StorageIOError

Error that occurs when operating the store.

StoredMembership

This struct represents information about a membership config that has already been stored in the raft logs.

Vote

Vote represent the privilege of a node.

Enums

ChangeMembers

Defines various actions to change the membership, including adding or removing learners or voters.

ConfigError

Error variants related to configuration.

ErrorSubject

ErrorVerb

What it is doing when an error occurs.

ServerState

All possible states of a Raft node.

SnapshotPolicy

Log compaction and snapshot policy.

StorageError

A storage error could be either a defensive check error or an error occurred when doing the actual io operation.

Violation

Violations a store would return when running defensive check.

Traits

AppData

A trait defining application specific data.

AppDataResponse

A trait defining application specific response data.

MessageSummary

Node

A Raft Node, this trait holds all relevant node information.

NodeId

A Raft node’s ID.

OptionalSend

OptionalSync

ToStorageResult

Convert error to StorageError::IO();

TryAsRef

Similar to AsRef<T>, it does a cheap reference to reference conversion, but with the ability to return None if it is unable to perform the conversion to &T.

Type Aliases

CommittedLeaderId

The unique identifier of a leader that is already granted by a quorum in phase-1(voting).

SnapshotId

Id of a snapshot stream.

Attribute Macros

add_async_trait

This proc macro attribute optionally adds Send bounds to a trait.