gistfile1.txt

defmodule Parallel do
  # Allows mapping over a collection using N parallel processes
  def pmap(collection, function) do
    # Get this process's PID
    me = self
    collection
    |>
    Enum.map(fn (elem) ->
      # For each element in the collection, spawn a process and
      # tell it to:
      # - Run the given function on that element
      # - Call up the parent process
      # - Send the parent its PID and its result
      # Each call to spawn_link returns the child PID immediately.
      spawn_link fn -> (send me, { self, function.(elem) }) end
    end) |>
    # Here we have the complete list of child PIDs. We don't yet know
    # which, if any, have completed their work
    Enum.map(fn (pid) ->
      # For each child PID, in order, block until we receive an
      # answer from that PID and return the answer
      # While we're waiting on something from the first pid, we may
      # get results from others, but we won't "get those out of the
      # mailbox" until we finish with the first one.
      receive do { ^pid, result } ->
        IO.puts result
      end
    end)
  end
end

HTTPoison.start

# Calculate squares of these numbers
parallelism = 20
Parallel.pmap(1..parallelism, fn(integer) ->
  IO.puts "getting animal #{integer}"
  # response = HTTPoison.get!("http://localhost:8888/animals/#{integer}", [], [recv_timeout: 1000000])
  response = HTTPoison.get!("http://localhost:8888/hello?name=#{integer}", [], [recv_timeout: 1000000])
  IO.puts "response for #{integer}: #{response.body}"
end)