Install Python 2.7 and Python 3.5 alongside Python 2.6 on CentOS 6.5

I got mostly from this post.

Install Python 2.7 and Python 3.5 alongside Python 2.6 on CentOS 6.5

1. Prep
# yum groupinstall "Development tools"
# yum install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel

2. Compile as shared library - add /usr/local/lib on /etc/ld.so.conf
# vi /etc/ld.so.conf
include ld.so.conf.d/*.conf
/usr/local/lib
# ldconfig

3.  Install python on  /usr/local
# Python 2.7.12:
wget http://python.org/ftp/python/2.7.12/Python-2.7.12.tar.xz
tar xf Python-2.7.12.tar.xz
cd Python-2.7.12
./configure --prefix=/usr/local --enable-unicode=ucs4 --enable-shared 
make && make altinstall

# Python 3.5.2:
wget http://python.org/ftp/python/3.5.2/Python-3.5.2.tar.xz
tar xf Python-3.5.2.tar.xz
cd Python-3.5.2
./configure --prefix=/usr/local --enable-shared
make && make altinstall

4. Run ldconfig again
# ldconfig

5. Install python virtualenv
# yum install python-virtualenv

6. Create virtualenv for python2.7
$ mkdir project_home
$ cd project_home
$ virtualenv -p /usr/local/bin/python2.7 .venv2.7

7. Create virtualenv for python3.5
$ mkdir project_home
$ cd project_home
$ pyvenv-3.5 .venv3.5
(this seems to work even though I get an error message:
Unable to symlink '/usr/local/bin/python3.5' to '/auto/home/delacs/python_projects_on_perf_utils/test_project/.venv3.5/bin/python3.5')

DRF JWT Authentication

i.e., Django REST Framework with JSON Web Token Authentication. Got the solution from here: http://getblimp.github.io/django-rest-framework-jwt/ http://zqpythonic.qiniucdn.com/data/20141006233346/index.html

$ pip install djangorestframework-jwt

In settings.py:
REST_FRAMEWORK = {
    'DEFAULT_PERMISSION_CLASSES': (
        'rest_framework.permissions.IsAuthenticated',
    ),
    'DEFAULT_AUTHENTICATION_CLASSES': (
        'rest_framework.authentication.BasicAuthentication',
        'rest_framework.authentication.SessionAuthentication',
        'rest_framework_jwt.authentication.JSONWebTokenAuthentication',
    ),
}

In urls.py:
from rest_framework_jwt.views import obtain_jwt_token, refresh_jwt_token

urlpatterns = patterns(
    # ...
    url(r'^api-token-auth/', obtain_jwt_token),
    url(r'^api-token-refresh/', refresh_jwt_token)
)

To test:
$ curl -X POST -d "username=admin&password=password123" http://localhost:8000/api-token-auth/
$ curl -X POST -H "Content-Type: application/json" -d '{"username":"admin","password":"password123"}' http://localhost:8000/api-token-auth/
$ curl -H "Authorization: JWT " http://localhost:8000/protected-url/

Django LDAP Integration

These posts helped me: http://kacperdziubek.pl/python/django-ldap-open-directory-integration/ https://pythonhosted.org/django-auth-ldap/

Install:
$ pip install django-auth-ldap

Then in settings.py, add:
import ldap
from django_auth_ldap.config import LDAPSearch

AUTHENTICATION_BACKENDS = (
    'django.contrib.auth.backends.ModelBackend',
    'django_auth_ldap.backend.LDAPBackend',
)

AUTH_LDAP_SERVER_URI = "ldap://my.appauth.com" # ip or host name of Open Directory server
AUTH_LDAP_BIND_DN = "CN=Accounts,OU=US Security,DC=corp,DC=com"
AUTH_LDAP_BIND_PASSWORD = "MySecurePassword"
AUTH_LDAP_USER_SEARCH = LDAPSearch("OU=US Users,dc=corp,dc=com",
    ldap.SCOPE_SUBTREE, "(sAMAccountName=%(user)s)")
AUTH_LDAP_CONNECTION_OPTIONS = {
    # make search fast
    ldap.OPT_REFERRALS: 0
}

AUTH_LDAP_USER_ATTR_MAP = {
    "username": "sAMAccountName",
    "first_name": "givenName",
    "last_name": "sn",
    "email": "mail"
}

The mapping above would result into automatically saving the information to the users table.

Django Notes

1. Backup and seed data using fixtures
# Save data
$ python manage.py dumpdata --format=json myapp > myapp/fixtures/initial_data.json
# Load data
$ python manage.py loaddata vlanapi/fixtures/initial_data.json

2. Open python shell - interactive console
$ python manage.py shell
Python 2.7.12 (default, Jul  1 2016, 15:12:24) 
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>>

3. Start a project
$ django-admin startproject mysite

4. Start initial migration
$ python manage.py migrate

5. Start server
$ python manage.py runserver

6. Create an app
$ python manage.py startapp newapp

7. Create and run a migration
$ python manage.py makemigrations
$ python manage.py migrate

Python Notes

1. Booleans
The numbers 0, 0.0, and 0+0j are all False; any other number is True.
The empty string "" is False; any other string is True.
The empty list [] is False; any other list is True.
The empty dictionary {} is False; any other dictionary is True.
The empty set set() is False; any other set is True.
The special Python value None is always False.

2. Working on REPL
Import library
>>> from autoinfra.resource import Client, Ddr, Resource
List all available methods
>>> dir(Client)
['__class__', '__delattr__', '__dict__', '__doc__', '__format__', '__getattribute__', '__hash__', '__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', '_connect_ssh', 'bring_up_eth', 'configure_ip', 'eth_filter', 'get_eths_details', 'get_eths_via_ifconfig', 'get_eths_via_ip_a', 'get_switch_port_details', 'is_connected', 'is_eth_link_detected', 'send_cmd']
Access docstring on a method
>>> help(Client.get_switch_port_details)

3. Testing
From this post.

$ pip install nose

From root of project run nosetests, this would look for any test under this directory and run it
$ pwd
/auto/home13/delacs/Documents/projects/nextgen/libs/autoinfra
$ nosetests
.....
----------------------------------------------------------------------
Ran 5 tests in 2.659s
OK

To run a single file
$ nosetests -v autoinfra/resources/tests/test_ddr.py
test_get_10g_eths (test_ddr.TestDdr) ... ok
test_se_cmd (test_ddr.TestDdr) ... ok
test_send_cmd (test_ddr.TestDdr) ... ok
----------------------------------------------------------------------
Ran 3 tests in 2.602s

To run a particular test in a file
$ nosetests -v autoinfra/switches/tests/test_cisco.py:TestCisco.test_move_to_vlan_no_nxapi_single
test_move_to_vlan_no_nxapi_single (test_cisco.TestCisco) ... ok
----------------------------------------------------------------------
Ran 1 test in 12.423s
OK

This works when test files have imports like this...
from autoinfra.resources.client import Client

4. Install python 2.7.12 on another directory (/opt/python)
# wget https://www.python.org/ftp/python/2.7.12/Python-2.7.12.tgz
# tar zxf Python-2.7.12.tgz
# cd Python-2.7.12/
# ./configure --prefix=/opt/python
# make
# make install

5. Create a virtual environment
$ sudo yum install python-virtualenv
$ mkdir sample_project
$ cd sample_project
$ virtualenv -p /opt/python/bin/python2.7 .venv

6. Data dumper
>>> from pprint import pprint
>>> pprint(vars(Host.objects.get(name="w3-perfsds-0001")))

Install TP-Link AC1200 T4U in Ubuntu 16.04

$ sudo apt-get install synaptic
search for rtl8812au-dkms and install
$ sudo service network-manager stop
$ sudo modprobe -rfv 8812au
$ sudo modprobe -v 8812au
$ sudo service network-manager start
$ sudo dkms status
rtl8812au, 4.3.8.12175.20140902+dfsg, 4.4.0-31-generic, x86_64: installed

Everytime kernel is updated, do these steps to recompile:
$ dkms status
$ sudo dkms remove rtl8812au/4.3.8.12175.20140902+dfsg -k $(uname -r)
$ sudo dkms install rtl8812au/4.3.8.12175.20140902+dfsg
$ sudo modprobe 8812au

Cron Like Program in Ruby with Clockwork

I like this gem I discovered called clockwork. A good replacement for cron plus more because you can do extra programming when scheduling jobs.

require 'clockwork'
module Clockwork
  handler do |job|
    puts "Running #{job}"
  end 

  # handler receives the time when job is prepared to run in the 2nd argument
  # handler do |job, time|
  #   puts "Running #{job}, at #{time}"
  # end

  every(1.hour, 'hourly.ms_status') do
    `cd $HOME/Documents/projects/monweb_management && $HOME/.rvm/wrappers/ruby-2.3.0@RailsDev/rake file:get_ms_status`
  end 

  every(1.day, 'daily.pbba_query', :at => '07:00') do
    `cd $HOME/Documents/projects/monweb_management && $HOME/.rvm/wrappers/ruby-2.3.0@RailsDev/rake file:get_pbba_sizing`
  end 
end

Then run it like this...

$ clockwork job_scheduler.rb
I, [2016-05-24T09:18:21.215569 #771]  INFO -- : Starting clock for 2 events: [ hourly.ms_status daily.pbba_query ]
I, [2016-05-24T09:18:21.215729 #771]  INFO -- : Triggering 'hourly.ms_status'