HRW.Skeleton (hrw v0.1.0)

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A skeleton-based variant of HRW that gives O(log n) lookups by grouping nodes into clusters and routing keys through a virtual tree.

Build the skeleton once with build/2, then pass it to each owner/3 call. The skeleton is plain data, not a process.

Summary

Types

t()

Functions

build(nodes, opts \\ [])

Builds a skeleton from nodes.

owner(key, skeleton, opts \\ [])

Returns the node responsible for key in the given skeleton.

Types

t()

@type t() :: %HRW.Skeleton{
  clusters: tuple(),
  fanout: pos_integer(),
  levels: non_neg_integer()
}

Functions

build(nodes, opts \\ [])

@spec build(
  [term()],
  keyword()
) :: t()

Builds a skeleton from nodes.

Options

  • :fanout - branching factor of the virtual tree. Defaults to 3.
  • :cluster_size - target number of nodes per cluster. Defaults to 16.

Examples

iex> HRW.Skeleton.build(["server1", "server2", "server3"])
#HRW.Skeleton<3 nodes, fanout: 3>

owner(key, skeleton, opts \\ [])

@spec owner(term(), t(), keyword()) :: term()

Returns the node responsible for key in the given skeleton.

Options

  • :hash_fn - a function term -> integer. Defaults to &:erlang.phash2/1.

Examples

iex> skeleton = HRW.Skeleton.build(["server1", "server2", "server3"])
iex> HRW.Skeleton.owner("192.168.0.2", skeleton)
"server3"