tverlaan / libcluster_db

Database-backed strategy for libcluster

LibclusterDb

This clustering strategy relies on nodes stored in a database.

You can have libcluster automatically connect nodes on startup for you by configuring the strategy like below:

config :libcluster,
  topologies: [
    db_config_example: [
      strategy: Cluster.Strategy.Database,
      config: [repo: MyApp.Repo, timeout: 30_000]
    ]
  ]

An optional timeout can be specified in the config. This is the timeout that will be used in the GenServer to connect the nodes. This defaults to :infinity meaning that the connection process will only happen when the worker is started. Any integer timeout will result in the connection process being triggered. In the example above, it has been configured for 30 seconds.

Installation

If available in Hex, the package can be installed by adding libcluster_db to your list of dependencies in mix.exs:

def deps do
  [
    {:libcluster_db, "~> 0.2.0"}
  ]
end

The docs can be found at https://hexdocs.pm/libcluster_db.

Migrate database

defmodule MyApp.Repo.Migrations.AddLibClusterDb do
  use Ecto.Migration

  def up do
    Cluster.Strategy.Database.Migration.up()
  end

  def down do
    Cluster.Strategy.Database.Migration.down()
  end
end