README
¶
dht
dht is a distributed hash table implementation that uses Consul
and rendezvous hashing to distribute keys among distributed
nodes. Because it uses rendezvous hashing to determine key placement, removing a
node from the hash table is minimally disruptive in terms of key re-assignment.
Local hash table state is refreshed in a background goroutine using blocking
Consul API queries with the default consistency mode. Errors
encountered in the background goroutine are logged using the log package in
the following format:
[dht <name> <id>] error: <error message>
dht requires a locally-running Consul agent (version 0.5.2 or newer) with its
HTTP API listening on 127.0.0.1:8500. dht nodes run a simple HTTP server on
an available ephemeral port to allow Consul to periodically check that the node
is still alive.
Example
node1, err := dht.Join("worker", "worker-1")
node2, err := dht.Join("worker", "worker-2")
node1.Member("some_key") // true
node2.Member("some_key") // false
err = node1.Leave()
err = node2.Leave()
Documentation
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Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Node ¶
type Node struct {
// contains filtered or unexported fields
}
Node is a single node in a distributed hash table, coordinated using services registered in Consul. Key membership is determined using rendezvous hashing to ensure even distribution of keys and minimal key membership changes when a Node fails or otherwise leaves the hash table.
Errors encountered when making blocking GET requests to the Consul agent API are logged using the log package.
func Join ¶
Join creates a new Node and adds it to the distributed hash table specified by the given name. The given id should be unique among all Nodes in the hash table.
func (*Node) Leave ¶
Leave removes the Node from the distributed hash table by de-registering it from Consul. Once Leave is called, the Node should be discarded. An error is returned if the Node is unable to successfully deregister itself from Consul. In that case, Consul's health check for the Node will fail and require manual cleanup.
Source Files