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:net_kernel.start([:"main@127.0.0.1"])
:erlang.set_cookie(:cook)
{:ok, peer, peername} =
   :peer.start(%{connection: 0, name: :peer, host: ~C'127.0.0.1'})
:peer.call(peer, :erlang, :set_cookie, [:cook])
Node.connect(peername)

# add code paths
:rpc.call(peername, :code, :add_paths, [:code.get_path()])

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.

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# ATTENTION: This is now supported in plug_cowboy as of 2.1.0:
# https://hexdocs.pm/plug_cowboy/Plug.Cowboy.Drainer.html

defmodule DrainStop do
  @moduledoc """
  DrainStop Attempts to gracefully shutdown an endpoint when a normal shutdown
  occurs. It first shuts down the acceptor, ensuring that no new requests can be
  made. It then waits for all pending requests to complete. If the timeout
  expires before this happens, it stops waiting, allowing the supervision tree
  to continue its shutdown order.

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#!/usr/bin/env bash
set -x

term_handler() {
  echo "Stopping the server process with PID $PID"
  erl -noshell -name "term@127.0.0.1" -eval "rpc:call('app@127.0.0.1', init, stop, [])" -s init stop
  echo "Stopped"
}

trap 'term_handler' TERM INT

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Dagger Demos

Summary

Dagger is a tool for modeling your workflows as data that can be composed together at runtime.

Dagger constructs can be integrated into a Dagger.Workflow and evaluated lazily in concurrent contexts.

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Getting Lazy with Dataflow Graphs in Elixir

Intro

What do Tensorflow, Apache Airflow, Rule Engines, and Excel have in common?

Under the hood they all use DAGs to model data-flow dependencies of the program. Using graphs to model programs is great because you can modify the program at runtime. Lets talk about doing this in Elixir for great good.

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UPDATED 3.12.2020

The old version of youtube with "disable_polymer" is not working anymore, so the script also stopped working.

Thanks to JanTheDeveloper we have a new working script. Big up!

I just changed the '//span[contains(text(),"Watch later")]', to '//span[contains(text(),"Remove from")]', and it should work for any playlist, not just the watch later one. (thanks to hudsonite for the tip)

setInterval(function () {
 document.querySelector('#primary button[aria-label="Action menu"]').click();

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Falsehoods programmers believe about prices

1. You can store a price in a floating point variable.
2. All currencies are subdivided in 1/100th units (like US dollar/cents, euro/eurocents etc.).
3. All currencies are subdivided in decimal units (like dinar/fils)
4. All currencies currently in circulation are subdivided in decimal units. (to exclude shillings, pennies) (counter-example: MGA)
5. All currencies are subdivided. (counter-examples: KRW, COP, JPY... Or subdivisions can be deprecated.)
6. Prices can't have more precision than the smaller sub-unit of the currency. (e.g. gas prices)
7. For any currency you can have a price of 1. (ZWL)
8. Every country has its own currency. (EUR is the best example, but also Franc CFA, etc.)

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Demonstrate Erlang's 'busy wait' effect on CPU utilization

How?

Just make Erlang to do some light-load task in a bunch of relatively short leaving processes. Calculating PI to 80th digit in batches per 10 procs with short, 8 ms, sleep in-between, to give schedulers a breath space, will do.

Running

Run erl with 8 schedulers and no busy waiting on schedulers at all.

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# file: code_lock.ex
# Translated from: http://erlang.org/doc/design_principles/statem.html#example-revisited
# callback mode: :handle_event_function
#
defmodule CodeLock do
  @behaviour :gen_statem
  @name :code_lock_2

  def start_link(code),
    do: :gen_statem.start_link({:local, @name}, __MODULE__, code, [])