Struct rings_core::dht::PeerRing

pub struct PeerRing {
    pub did: Did,
    pub finger: Arc<Mutex<FingerTable>>,
    pub successor_seq: SuccessorSeq,
    pub predecessor: Arc<Mutex<Option<Did>>>,
    pub storage: VNodeStorage,
    pub cache: VNodeStorage,
}

PeerRing is used to help a node interact with other nodes. All nodes in rings network form a clockwise ring in the order of Did. This struct takes its name from that. PeerRing implemented Chord algorithm. PeerRing implemented ChordStorage protocol.

Fields

did: Did

The did of current node.

finger: Arc<Mutex<FingerTable>>

FingerTable help node to find successor quickly.

successor_seq: SuccessorSeq

The next node on the ring. The SuccessorSeq may contain multiple node dids for fault tolerance. The min did should be same as the first element in finger table.

predecessor: Arc<Mutex<Option<Did>>>

The did of previous node on the ring.

storage: VNodeStorage

Local storage for ChordStorage.

cache: VNodeStorage

Local cache for ChordStorage.

Implementations

impl PeerRing

pub fn new_with_storage(did: Did, succ_max: u8, storage: VNodeStorage) -> Self

Same as new with config, but with a given storage.

pub fn lock_successor(&self) -> Result<SuccessorSeq>

👎Deprecated

Return successor sequence. This function is deprecated, please use [chord.successors] instead.

pub fn successors(&self) -> SuccessorSeq

Return successor sequence

pub fn lock_finger(&self) -> Result<MutexGuard<'_, FingerTable>>

Lock and return MutexGuard of finger table.

pub fn lock_predecessor(&self) -> Result<MutexGuard<'_, Option<Did>>>

Lock and return MutexGuard of predecessor.

pub fn remove(&self, did: Did) -> Result<()>

Remove a node from finger table. Also remove it from successor sequence. If successor_seq become empty, try setting the closest node to it.

pub fn bias(&self, did: Did) -> BiasId

Calculate bias of the Did on the ring.

Trait Implementations

impl Chord<PeerRingAction> for PeerRing

fn join(&self, did: Did) -> Result<PeerRingAction>

Join a ring containing a node identified by did. This method is usually invoked to maintain successor sequence and finger table after connect to another node.

This method will return a RemoteAction::FindSuccessorForConnect to the caller. The caller will send it to the node identified by did, and let the node find the successor of current node and make current node connect to that successor.

fn find_successor(&self, did: Did) -> Result<PeerRingAction>

Find the successor of a Did. May return a remote action for the successor is recorded in another node.

fn notify(&self, did: Did) -> Result<Did>

Handle notification from a node that thinks a did is the predecessor of current node. The did in parameters is the Did of that predecessor. If that node is closer to current node or current node has no predecessor, set it to the did. This method will return current predecessor after setting.

fn fix_fingers(&self) -> Result<PeerRingAction>

Fix finger table by finding the successor for each finger. According to the paper, this method should be called periodically. According to the paper, only one finger should be fixed at a time.

impl<const REDUNDANT: u16> ChordStorage<PeerRingAction, REDUNDANT> for PeerRing

fn vnode_lookup<'life0, 'async_trait>( &'life0 self, vid: Did ) -> Pin<Box<dyn Future<Output = Result<PeerRingAction>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Look up a VirtualNode by its Did. Always finds resource by finger table, ignoring the local cache. If the vid is between current node and its successor, its resource should be stored in current node.

fn vnode_operate<'life0, 'async_trait>( &'life0 self, op: VNodeOperation ) -> Pin<Box<dyn Future<Output = Result<PeerRingAction>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Handle VNodeOperation if the target vnode between current node and the successor of current node, otherwise find the responsible node and return as Action.

impl ChordStorageCache<PeerRingAction> for PeerRing

fn local_cache_put<'life0, 'async_trait>( &'life0 self, vnode: VirtualNode ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Cache fetched vnode locally.

fn local_cache_get<'life0, 'async_trait>( &'life0 self, vid: Did ) -> Pin<Box<dyn Future<Output = Result<Option<VirtualNode>>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Get vnode from local cache.

impl ChordStorageSync<PeerRingAction> for PeerRing

fn sync_vnode_with_successor<'life0, 'async_trait>( &'life0 self, new_successor: Did ) -> Pin<Box<dyn Future<Output = Result<PeerRingAction>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

When the successor of a node is updated, it needs to check if there are VirtualNodes that are no longer between current node and new_successor, and sync them to the new successor.

impl CorrectChord<PeerRingAction> for PeerRing

fn update_successor<'life0, 'async_trait>( &'life0 self, did: impl 'async_trait + LiveDid ) -> Pin<Box<dyn Future<Output = Result<PeerRingAction>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

When Chord have a new successor, ask the new successor for successor list

fn join_then_sync<'life0, 'async_trait>( &'life0 self, did: impl 'async_trait + LiveDid ) -> Pin<Box<dyn Future<Output = Result<PeerRingAction>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Join Operation in the paper. Zave’s work differs from the original Chord paper in that it requires a newly joined node to synchronize its successors from remote nodes.

fn rectify(&self, pred: Did) -> Result<()>

TODO: Please check this function and make sure it is correct. TODO: Please comment this with clear description. Rectify Operation in the paper.

fn pre_stabilize(&self) -> Result<PeerRingAction>

Pre-Stabilize Operation: Before stabilizing, the node should query its first successor for TopoInfo. If there are no successors, return PeerRingAction::None.

fn stabilize(&self, info: TopoInfo) -> Result<PeerRingAction>

Stabilize Operation: Perform stabilization for the successor list.

fn topo_info(&self) -> Result<TopoInfo>

A function to provide topological information about the chord.

fn extend_successor<'life0, 'life1, 'async_trait>( &'life0 self, dids: &'life1 [impl 'async_trait + LiveDid] ) -> Pin<Box<dyn Future<Output = Result<PeerRingAction>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Hook of updating successor

impl TryFrom<&PeerRing> for TopoInfo

type Error = Error

The type returned in the event of a conversion error.

fn try_from(dht: &PeerRing) -> Result<TopoInfo>

Performs the conversion.