jwhiteman

# elixir
defmodule Example do
  def work(_msg) do
    IO.puts "called 1st function"
  end

  def work(_msg, data=[_a, _b, _c]) do
    IO.puts "called 2nd function #{inspect data}"
  end

jwhiteman

sudo apt-get update
sudo apt-get install vim

# generate keys and copy them over
ssh-copy-id -i id_rsa.pub vagrant@hnclient # move node ssh key to the client
# update /etc/hosts on each node to know at least the master; the master about the slave nodes
# make sure master can ssh into localost
cat .ssh/id_rsa.pub >> .ssh/authorized_keys

# re-read: http://stackoverflow.com/questions/8872807/hadoop-datanodes-cannot-find-namenode

jwhiteman

# http://is.gd/NzZxYT

defmodule BinaryTree do
  def invert([n, list]) when is_integer(n) and is_list(list) do
    [n, invert(list)]
  end
  def invert([n, nc, m, mc])
      when is_integer(n) and is_integer(m)
      and is_list(nc) and is_list(mc) do

jwhiteman

require "thread"

stage_one    = Queue.new
stage_two    = Queue.new
stage_three  = Queue.new

stage_one_worker = Thread.new do
  100.times do |n|
    stage_one << n
    

jwhiteman

# A reminder that join conceptually combines the stacks of the parent and child threads.
# If you consider that the stack grows downard, the child stack will sit below the parent
# stack. See output below.
def main?
  Thread.current == Thread.main
end

def name
  if main?
    "main"

jwhiteman

strace cmd 2> /dev/stdout | cut -d '(' -f 1 | sort | uniq | grep -v "[+=]" | sort -rn -k1,1

jwhiteman

# or `echo some-request | nc localhost 8181 -4u `
MAX_READ = 1024 * 8
FLAGS    = 0

c = Socket.new :INET, :DGRAM
s = Socket.pack_sockaddr_in 8181, "127.0.0.1"

c.send("some-request", FLAGS, s)

res = c.recv(MAX_READ)

jwhiteman

require 'httparty'
require 'redis'
require 'json'
require 'timeout'

$publisher  = Redis.new
$subscriber = Redis.new

CHANNEL = 'omg'

jwhiteman

defmodule DFA do
  def accepts?(accept: accept_states, rules: rules, s: string) do
    string
    |> String.graphemes
    |> List.foldl(1, fn(char, state) -> next(state: state, char: char, rules: rules) end)
    |> member?(accept_states)
  end

  defp next(state: nil, char: _char, rules: _rules) do
    nil

jwhiteman

=begin
{
    "AccessKey": {
        "UserName": "s3.deploy.foo",
        "Status": "Active",
        "CreateDate": "2016-11-04T16:25:27.123Z",
        "SecretAccessKey": "secret",
        "AccessKeyId": "access"
    }
}