proxy_benchmark.exs

defmodule Web do
  # $ elixir -v
  # Erlang/OTP 19 [erts-8.1] [source] [64-bit] [smp:4:4] [async-threads:10] [kernel-poll:false]
  #
  # Elixir 1.3.4

  # MATCH CASES
  # *** &Web.cond_and_regex_match/1 ***
  # 1.6 sec     2M iterations   0.78 μs/op
  #
  # *** &Web.string_split_and_map_get/1 ***
  # 1.2 sec     2M iterations   0.59 μs/op
  #
  # NO MATCH CASES
  # *** &Web.cond_and_regex_match/1 ***
  # 1.5 sec     2M iterations   0.73 μs/op
  #
  # *** &Web.string_split_and_map_get/1 ***
  # 1.2 sec     2M iterations   0.59 μs/op

  defmodule Endpoint1 do; end
  defmodule Endpoint2 do; end
  defmodule Endpoint3 do; end
  defmodule Endpoint4 do; end
  defmodule Endpoint5 do; end

  def cond_and_regex_match(path) do
    cond do
      # path =~ ~r{/bar} -> Endpoint2
      # path =~ ~r{/baz} -> Endpoint3
      # path =~ ~r{/boo} -> Endpoint4
      path =~ ~r{/foo} -> Endpoint1
      true             -> Endpoint5
    end
  end

  @path_prefixes %{"foo" => Endpoint1}
  def string_split_and_map_get(path) do
    [_, prefix | _] = String.split(path, "/")
    Map.get @path_prefixes, prefix, Endpoint5
  end

  def benchmark do
    funcs = [
      &__MODULE__.cond_and_regex_match/1,
      &__MODULE__.string_split_and_map_get/1
    ]

    IO.puts "MATCH CASES"
    path = "/foo/bar/123/baz"
    Benchwarmer.benchmark funcs, path

    IO.puts "NO MATCH CASES"
    path = "/foo/bar/123/baz"
    Benchwarmer.benchmark funcs, path
  end
end

proxy_benchmark_equivalent.rb

module Web
  module Endpoint1; end
  module Endpoint2; end
  module Endpoint3; end
  module Endpoint4; end
  module Endpoint5; end

  def self.cond_and_regex_match(path)
    ### "cond + regex match" equiv ###
    if path =~ %r[/foo] then Web::Endpoint1
      # elsif path =~ %r[/bar] then Web::Endpoint2
      # elsif path =~ %r[/baz] then Web::Endpoint3
      # elsif path =~ %r[/boo] then Web::Endpoint4
    else Web::Endpoint5 end
    # alternatively `case`
  end

  @@path_prefixes = { "foo" => Web::Endpoint1 }
  def self.string_split_and_map_get(path)
    ### "String.split/2 + Map.get/3" equiv ###
    _, prefix = path.split(?/) # path.split(?/)[1]
    @@path_prefixes.fetch(prefix, Web::Endpoint5)
  end
end

path = "/foo/bar/123/baz"

puts Web.cond_and_regex_match(path)
puts Web.cond_and_regex_match("miss")
puts Web.string_split_and_map_get(path)
puts Web.string_split_and_map_get("miss")