Documentation
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Index ¶
- type AcceptedValue
- type GossipState
- type Node
- type NodeClaims
- type NodeID
- type Observer
- func (observer *Observer) Consensus() (bool, AcceptedValue)
- func (observer *Observer) GossipState() GossipState
- func (observer *Observer) IsElector() bool
- func (observer *Observer) Propose()
- func (observer *Observer) SetQuorum(uint)
- func (observer *Observer) Think() bool
- func (observer *Observer) Update(from GossipState) bool
- type Participant
- type ProposalID
- type Status
- type Value
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type AcceptedValue ¶
type AcceptedValue struct {
Value Value
Origin ProposalID
}
An AcceptedValue is a Value plus the proposal which originated that Value. The origin is not essential, but makes comparing AcceptedValues easy even if comparing Values is not.
type GossipState ¶
type GossipState map[NodeID]NodeClaims
type Node ¶
type Node struct {
// contains filtered or unexported fields
}
func (*Node) Consensus ¶
func (node *Node) Consensus() (bool, AcceptedValue)
Has a consensus been reached, based on the known claims of other nodes?
func (*Node) GossipState ¶
func (node *Node) GossipState() GossipState
func (*Node) Propose ¶
func (node *Node) Propose()
Initiate a new proposal, i.e. the Paxos "Prepare" step. This is simply a matter of gossipping a new proposal that supersedes all others.
func (*Node) Think ¶
The heart of the consensus algorithm. Return true if we have changed our claims.
func (*Node) Update ¶
func (node *Node) Update(from GossipState) bool
Update this node's information about what other nodes know. Returns true if we learned something new.
type NodeClaims ¶
type NodeClaims struct {
// The node promises not to accept a proposal with id less
// than this.
Promise ProposalID
// The accepted proposal, if valid
Accepted ProposalID
AcceptedVal AcceptedValue
}
type NodeID ¶
The node identifier. The use of the UID here is important: Paxos acceptors must not forget their promises, so it's important that a node does not restart and lose its Paxos state but claim to have the same ID.
type Observer ¶
type Observer struct {
}
func (*Observer) Consensus ¶
func (observer *Observer) Consensus() (bool, AcceptedValue)
func (*Observer) GossipState ¶
func (observer *Observer) GossipState() GossipState
func (*Observer) Update ¶
func (observer *Observer) Update(from GossipState) bool
type Participant ¶
type Participant interface {
GossipState() GossipState
Update(from GossipState) bool
SetQuorum(uint)
Propose()
Think() bool
Consensus() (bool, AcceptedValue)
IsElector() bool
}
func NewObserver ¶
func NewObserver() Participant
type ProposalID ¶
type ProposalID struct {
// round numbers begin at 1. round 0 indicates an
// uninitialized ProposalID, and precedes all other ProposalIDs
Round uint
Proposer NodeID
}
note all fields exported in structs so we can Gob them
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