class

Clustering

Inherits Reference < Object

Constants

Log = ::Log.for(self)

Constructors

new(uri : String | URI, name : String = ULID.generate, discovery : HoundDog::Discovery | Nil = nil, etcd_host : String = ENV["ETCD_HOST"]? || "localhost", etcd_port : Int32 = ENV["ETCD_PORT"]?.try(&.to_i?) || 2379)

Class methods

election_key

meta_namespace

readiness_key

service_namespace

Instance methods

cluster_change

Leader publishes a new version upon nodes joining/leaving the cluster

cluster_consistent?

When there's an event under the readiness namespace, node creates a hash from node to version. If all the nodes are at the same version, the cluster is consistent.

cluster_version

The version the current node is stable against

consume_stabilization_events

Consume stabilization events until fiber channel empty

Ensures that the node will have only the latest version

discovery

Provides cluster node discovery

etcd_client

Generate a new Etcd client

handle_readiness_event

The leader calls the on_stable callback if...

cluster's version state is consistent
consistent state has not already been confirmed to be consistent

handle_version_change(value)

Leader has published a new version to etcd

leader?

Whether node is the cluster leader

leader_node

Attains the current leader node

name(*args, **options)

name(*args, **options, &)

node_versions

nodes(*args, **options)

nodes(*args, **options, &)

retry_on_missing_lease

Retry a query if a lease is missing for at most the maximum requested lease TTL

service(*args, **options)

service(*args, **options, &)

stabilize

Performed to align nodes in the cluster

start

Starts the node's clustering processes.

discovery (via hound-dog)
election_watcher (election event consumer)
readiness_watcher (cluster node version event consumer)
version_watcher (version change event consumer)
consume_stabilization_events (created by version_watcher)

start(on_stable : String -> Nil | Nil = nil, &stabilize : Array(HoundDog::Service::Node) -> Bool)

Like above. Accepts a block that will be called with cluster nodes during stabilization events

If stabilize callback is true, the node is marked as ready.

stop

Unregisters node from the cluster and ceases event handling

uri(*args, **options)

uri(*args, **options, &)