Custom address resolution policy

Ruby driver uses plug-able address-resolution policy to map Apache Cassandra node’s ip address to another address value if necessary.

Using a custom address resolution strategy

Given

a running cassandra cluster in 2 datacenters with 2 nodes in each

And

a file named “custom_address_resolver.rb” with:

class CustomAddressResolver
  def initialize(addresses)
    @addresses = addresses
  end

  def resolve(address)
    @addresses.fetch(address, address)
  end
end

And

the following example:

require 'cassandra'
require 'custom_address_resolver'

resolver  = CustomAddressResolver.new({
  IPAddr.new('127.0.0.3') => IPAddr.new('192.168.10.3'),
  IPAddr.new('127.0.0.4') => IPAddr.new('192.168.10.4')
})
cluster   = Cassandra.cluster(address_resolution_policy: resolver)

puts cluster.each_host.map!(&:ip).sort!

When

it is executed

Then

its output should contain:

127.0.0.1
127.0.0.2
192.168.10.3
192.168.10.4