rmoorman

; FIXME: The grammar has been transformed so that `w` appears after a
; token, but there is no way in ABNF to define it as token-separator
; that can optionally contain a mix of comments and white-space. Take
; `;;` as an example, for that to match `sql-stmt-list` `w` would
; have to match the empty string. But if `w` matches the empty string
; then `ISNOT` is the same as `IS NOT`.

sql-stmt-list = [ sql-stmt ] *( ";" w [ sql-stmt ] )
sql-stmt = [ "EXPLAIN" w [ "QUERY" w "PLAN" w ] ] ( alter-table-stmt / analyze-stmt / attach-stmt / begin-stmt / commit-stmt / create-index-stmt / create-table-stmt / create-trigger-stmt / create-view-stmt / create-virtual-table-stmt / delete-stmt / delete-stmt-limited / detach-stmt / drop-index-stmt / drop-table-stmt / drop-trigger-stmt / drop-view-stmt / insert-stmt / pragma-stmt / reindex-stmt / release-stmt / rollback-stmt / savepoint-stmt / select-stmt / update-stmt / update-stmt-limited / vacuum-stmt )
alter-table-stmt = "ALTER" w "TABLE" w [ schema-name w "." w ] table-na

rmoorman

#!/bin/bash

ip=`echo $SSH_CONNECTION | cut -d " " -f 1`
hostname=`hostname`
fqdn=`hostname -f`

logger -t ssh-wrapper $USER login from $ip

sendmail -t <<EOF
To: Alex <adzhurinskij@gmail.com>

rmoorman

#!/usr/bin/ruby
# chkconfig: 35 99 01
# description: EC2 DNS registration
# processname: ec2hostname

require 'aws-sdk'
require 'net/http'

`touch /var/lock/subsys/ec2hostname`

rmoorman

#!/usr/bin/ruby
# chkconfig: 35 99 01
# description: EC2 DNS loadbalancing
# processname: ec2hostname

require 'aws-sdk'
require 'net/http'

`touch /var/lock/subsys/ec2hostname`

rmoorman

AWS CLI command to update CNAME

When you have a set of application servers running in EC2 in an active/passive configuration, the easiest way to failover is to simply update the DNS to point to the second server as soon as it's available to serve requests. If you are using Route 53 to manage your DNS configuration, with the AWS CLI you can make this change in a single command.

Initial Setup

• Install the AWS CLI
• Login with an account that has an IAM Policy that gives it access to the Route53 Service
• Get the HostedZoneID for the domain you want to update from the AWS console here: https://console.aws.amazon.com/route53/home#hosted-zones:

The CLI expects the change to be submitted via a JSON-formatted configuration file. I've inclu

rmoorman

defmodule YourApp.Validators.Email do
  use Ecto.Changeset
  @mail_regex ~r/^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,4}$/
  # ensure that the email looks valid
  def validate_email(changeset, field) do
    changeset
    |> validate_format(field, @mail_regex)
  end 
end

rmoorman

defmodule App.RegistrationController do
  use App.Web, :controller
  alias App.{Registration, Repo}

  def new(conn, _params) do
    changeset = Registration.changeset(%Registration{})
    render conn, :new, changeset: changeset
  end

  def create(conn, %{"registration" => registration_params}) do

rmoorman

Renaming table in Ecto migration

I recently wanted to rename a model and its postgres table in a Phoenix app. Renaming the table was simple and documented, but the table also had constraints, sequences, and indexes that needed to be updated in order for the Ecto model to be able to rely on default naming conventions. I couldn't find any examples of what this would look like but was eventually able to figure it out. For anyone else in the same situation, hopefully this example helps.

In the example below, I'm renaming the Permission model to Membership. This model belongs to a User and an Account, so it has foreign key constraints that need to be renamed.

defmodule MyApp.Repo.Migrations.RenamePermissionsToMemberships do
  use Ecto.Migration

rmoorman

defmodule App.Registration do
  use App.Web, :model
  alias App.{Account, User, Membership, Repo}

  embedded_schema do
    field :email
    field :org_name
  end

  @required_fields ~w(email org_name)a

rmoorman

#!/usr/bin/python
# -*- coding: utf-8 -*-

def xpath_soup(element):
    # type: (typing.Union[bs4.element.Tag, bs4.element.NavigableString]) -> str
    """
    Generate xpath from BeautifulSoup4 element.

    :param element: BeautifulSoup4 element.
    :type element: bs4.element.Tag or bs4.element.NavigableString