CachexMemoize

CachexMemoize provides straightforward memoization macros using Cachex as a backend.

How to memoize

If you want to cache a function, use CachexMemoize on the module and change def to defmemo and specify a cache. IMPORTANT! If your cache is not started the function will run directly without Cachex. If this behaviour is not desirable You can provide a fail parameter.

for example:

defmodule Example do
  def f(x) do
    Process.sleep(1000)
    make_ref()
  end
end

this code changes to:

Cachex.start(:mycache) # Normally you would `start_link` Cachex in a supervisor.

defmodule Example do
  use CachexMemoize
  defmemo f(x), cache: :mycache do
    Process.sleep(1000)
    make_ref()
  end
end

If a function defined by defmemo raises an error, the result is not cached and one of waiting processes will call the function.

Exclusive

A caching function that is defined by defmemo is never called in parallel.

Cachex.start(:mycache)
defmodule Calc do
use Memoize
    defmemo calc(), cache: :mycache do
      Process.sleep(1000)
      IO.puts "called!"
    end
end

# call `Calc.calc/0` in parallel using many processes.
for _ <- 1..10000 do
  Process.spawn(fn -> Calc.calc() end, [])
end

# but, actually `Calc.calc/0` is called only once.

Installation

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

def deps do
  [
    {:cachex_memoize, "~> 0.1.0"}
  ]
end

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/cachex_memoize.