earthgecko

#!/bin/bash
# bash generate random alphanumeric string
#

# bash generate random 32 character alphanumeric string (upper and lowercase) and 
NEW_UUID=$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 32 | head -n 1)

# bash generate random 32 character alphanumeric string (lowercase only)
cat /dev/urandom | tr -dc 'a-z0-9' | fold -w 32 | head -n 1

cpjolicoeur

I'm hunting for the best solution on how to handle keeping large sets of DB records "sorted" in a performant manner.

Problem Description

Most of us have work on projects at some point where we have needed to have ordered lists of objects. Whether it be a to-do list sorted by priority, or a list of documents that a user can sort in whatever order they want.

A traditional approach for this on a Rails project is to use something like the acts_as_list gem, or something similar. These systems typically add some sort of "postion" or "sort order" column to each record, which is then used when querying out the records in a traditional order by position SQL query.

This approach seems to work fine for smaller datasets, but can be hard to manage on large data sets with hundreds (or thousands) of records needing to be sorted. Changing the sort position of even a single object will require updating every single record in the database that is in the same sort group. This requires potentially thousands of wri

chenzhan

# List all tables:
select db_id, id, name, sum(rows) as mysum 
from stv_tbl_perm where db_id = 100546 
group by db_id, id, name order by mysum desc;

# list all running processes:
select pid, query from stv_recents where status = 'Running';

# describe table
select * from PG_TABLE_DEF where tablename='audit_trail';

ostinelli

Erlang Release init.d script

If you have packaged your application into a release generated with Rebar, you might want to have the following:

• The release started on system boot.
• The VM monitored and restarted it if it crashes.

Use HEART

HEART is the Heartbeat Monitoring of an Erlang Runtime System. The purpose of the heart port program is to check that the Erlang runtime system it is supervising is still running, so that if the VM crashes or becomes unresponsive, it is restarted.

henrik

# TODO:
# Runner like https://github.com/elixir-lang/ecto/blob/master/lib/ecto/migration.ex (does it have state?)

defmodule Ecto.Runner do
  def start_command({:create, table}) do
    IO.puts "create table: #{table}"
  end

  def subcommand({:add, column, type}) do
    IO.puts "add column: #{column}(#{type})"

zabirauf

defmodule Expng do

  defstruct [:width, :height, :bit_depth, :color_type, :compression, :filter, :interlace, :chunks]

  def png_parse(<<
  0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A,
                 _length :: size(32),
                 "IHDR",
                 width :: size(32),
                 height :: size(32),

henrik

defmodule HttpRequester do
  use GenServer

  def start_link(_) do
    GenServer.start_link(__MODULE__, nil, [])
  end

  def fetch(server, url) do
    # Don't use cast: http://blog.elixirsips.com/2014/07/16/errata-dont-use-cast-in-a-poolboy-transaction/
    timeout_ms = 10_000

keathley

defprotocol Functor do
  def fmap(data, func)
end

defprotocol Applicative do
  def pure(data)
  def run(wrapped_func, data)
end

defprotocol Monad do

subfuzion

Common Options

-#, --progress-bar Make curl display a simple progress bar instead of the more informational standard meter.

-b, --cookie <name=data> Supply cookie with request. If no =, then specifies the cookie file to use (see -c).

-c, --cookie-jar <file name> File to save response cookies to.

moklett

# This demonstrates that, when using async/await, a crash in the task will crash the caller
defmodule Tasker do
  def good(message) do
    IO.puts message
  end

  def bad(message) do
    IO.puts message
    raise "I'm BAD!"
  end