In order to remove docker images, first see your images and their corresponding id:

sudo docker images

Now to remove an image just use rmi as below:

sudo docker rmi b0c8cfb8fdb3

b0c8cfb8fdb3 is IMAGE ID to be removed.

#docker #image #rmi #remove

In the last tutorial we designed a project. Project holds the whole infrastructure, it can contain multiple apps. A weblog, an eshop page, poll app could all be an app in our newly created project. The examples are endless.

After project creation to create an app you can use startapp. For now we create a poll app:

$ python manage.py startapp polls
$

The structure of the polls app should be as below:

polls/
    __init__.py
    admin.py
    apps.py
    migrations/
        __init__.py
    models.py
    tests.py
    views.py

All the poll application logic resides here.

We try first by creating a view that return a sample http response. For writing view for your polls application you have to put it inside of views.py:

from django.http import HttpResponse


def index(request):
    return HttpResponse("Hello, world. You're at the polls index.")

Yes! That's it. We have created view in django. But for calling this view from outside you have to map a route to it. In my app I don't have the file urls.py so create it in polls and map as below:

from django.conf.urls import url

from . import views

urlpatterns = [
    url(r'^$', views.index, name='index'),
]

url is django module to implement the routing functionality.

The next step is to bind the newly defined route in polls to your project urls route. So for now go to saturn/urls.py:

from django.conf.urls import include, url
from django.contrib import admin

urlpatterns = [
    url(r'^polls/', include('polls.urls')),
    url(r'^admin/', admin.site.urls),
]

The first url says that give every route that starts with polls to polls.urls. You can see that we have used include to reference URL configuration. When it reaches /polls it removes polls and send the remaining of the URL to polls.

Now run your project with the command below and see the result:

$ python manage.py runserver

The final step is to open your browser and point it to /polls and see the result:

http://127.0.0.1:8000/polls/

Voila! Good job everybody :)

If you go to base path you will see the error below (see the picture):

#django #url #include #views #pattern #django_part3

To install your python module you need a setup.py file inside of your project. The content of the setup.py can be something like below:

setup(name=PROJECT_NAME,
       version=PROJECT_VERSION,
       description=PROJECT_DESCRIPTION,
       long_description=PROJECT_LONG_DESCRIPTION,
       author='Ali',
       author_email='info@ali.com',
       url='http://www.ali.com/',
       license='SOMETHING',
       entry_points=PROJECT_ENTRY_POINTS,
       classifiers=[],
       keywords='',
       packages=find_packages(exclude=['ez_setup', 'examples', 'tests']),
       include_package_data=True,
       namespace_packages=[],
       install_requires=['LIST', 'OF', 'REQUIREMENTS'],
       zip_safe=False,
       test_suite='nose.collector')

Now if you want to install it on your machine as a package just:

python setup.py install

If you want to upload it into your python repository:

python setup.py sdist upload -r my_repo

NOTE: you should be in the root of your project before running the previous command.

my_repo server should be declared inside of ~/.pypirc:

[distutils]
  index-servers =
      my_repo

  [my_repo]
  repository: http://pypi.repo.my_host.com:5000
  username: username
  password: password

If you want to install something from your repository via pip you have to provide the extra-index-url argument:

--extra-index-url http://username:password@pypi.repo.my_host.com:5000 --trusted-host pypi.repo.my_host.com

NOTE: you can put inside of an ENV variable in OS to access it better and in more readable way.

#python #setuppy #setup #package #pypi #private_repo #pypirc #pip #install

In this session we'll have a brief look at the settings.py file and do a migration for the saturn project.

To setup your database you need to give the credential in saturn/settings.py in the section:

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
    }
}

As you see above the default database is set to sqlite3 and the NAME of the database is set to file path of db.sqlite3, if your database is set to MySQL you would have to provide the name of the database in NAME section.

ENGINE can have one of the below database bindings:

'django.db.backends.sqlite3',
'django.db.backends.postgresql',
'django.db.backends.mysql',
'django.db.backends.oracle'

If you are using a db other than sqlite like MySQL you should provide USER, PASSWORD HOST beside ENGINE and NAME.

INSTALLED_APPS is a section that contains apps used by
our project. For example for session management there is django.contrib.sessions section.

Some of these applications use database tables, so for Django apps to work properly, youn need to use migrate command
and create corresponding tables:

$ python manage.py migrate
Operations to perform:
  Apply all migrations: admin, auth, contenttypes, sessions
Running migrations:
  Applying contenttypes.0001_initial... OK
  Applying auth.0001_initial... OK
  Applying admin.0001_initial... OK
  Applying admin.0002_logentry_remove_auto_add... OK
  Applying contenttypes.0002_remove_content_type_name... OK
  Applying auth.0002_alter_permission_name_max_length... OK
  Applying auth.0003_alter_user_email_max_length... OK
  Applying auth.0004_alter_user_username_opts... OK
  Applying auth.0005_alter_user_last_login_null... OK
  Applying auth.0006_require_contenttypes_0002... OK
  Applying auth.0007_alter_validators_add_error_messages... OK
  Applying auth.0008_alter_user_username_max_length... OK
  Applying sessions.0001_initial... OK

You can see that needed tables are created as above. In case you don't need an app just comment it out from INSTALLED_APPS before running migration.

The next session we would create models for our tables and would do the real parts. :)

#python #django #settings #INSTALLED_APPS #migration #database #ENGINE #django_part4

Install a specific version of NODEJS on linux server:

https://askubuntu.com/questions/957439/how-to-install-a-specific-version-of-node-on-ubuntu-server

#ubuntu #linux #nodejs #node #versioin #installation

Install NPM packages from http or https:

npm config set registry https://registry.npmjs.org/

Sometimes because of filtering issues you need to download node packages from http so make sure to make it http:

npm config set registry http://registry.npmjs.org/

#node #npm #shit #installation #config

If you have Mac system and created bash scripts so far, there is a fun feature on OS X that you can type say command. say will say the phrase:

say hello channel users

Or let's say you have a bash script that will take a lot of time and at the end of the script your want to hear operation done successfully from your speaker:

say operation done successfully

#osx #say #command #fun

There is a command in osX called open that will open finder for you from within of your terminal.

The great thing about this command is that you can open finder when you have traversed a long path and now you want it to have inside of finder. Go to the desired directory in your terminal using cd then use:

open .

it will open you finder. :)

#osx #open #command #fun #trick

If you get the below error for cross device link when installing npm on container:

npm WARN optional Skipping failed optional dependency /webpack/watchpack/chokidar/fsevents:
npm WARN notsup Not compatible with your operating system or architecture: fsevents@1.0.12
npm ERR! Linux 3.16.0-4-amd64
npm ERR! argv "/usr/local/bin/node" "/usr/local/bin/npm" "install"
npm ERR! node v6.3.0
npm ERR! npm  v3.10.3
npm ERR! path /app/node_modules/istanbul/node_modules/abbrev
npm ERR! code EXDEV
npm ERR! errno -18
npm ERR! syscall rename

npm ERR! EXDEV: cross-device link not permitted, rename '/app/node_modules/istanbul/node_modules/abbrev' -> '/app/node_modules/abbrev'
npm ERR! 
npm ERR! If you need help, you may report this error at:
npm ERR!     <https://github.com/npm/npm/issues>

npm ERR! Please include the following file with any support request:
npm ERR!     /app/npm-debug.log
The command '/bin/sh -c npm install' returned a non-zero code: 238

To solve this problem, put the below line of code before any npm command:

RUN cd $(npm root -g)/npm && npm install fs-extra && sed -i -e s/graceful-fs/fs-extra/ -e s/fs.rename/fs.move/ ./lib/utils/rename.js

reference: https://github.com/npm/npm/issues/13306
#npm #docker #container #cross_device

Today in django tutorial series we define 2 models in polls/models.py. One for Question and another for Choice.

from django.db import models
class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField('date published')

class Choice(models.Model):
    question = models.ForeignKey(Question, on_delete=models.CASCADE)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)

Our model's parent class is django models.Model and each model has its own fields. You can define string field by CharField, integer by IntegerField and datetime by DateTimeField.

* The name of each field is the column name in the table.

* max_length can be given as an argument to put restrictions on field's length

* you can give a human readable name to each field by providing an optional first positional argument like pub_date which is set to date published

* you can define foreign keys by models.ForeignKey

* fields can have default value is we have set for votes by using default

Until now Django knows nothing about our polls app, we need to plug it in, in order to include it in our project. Go to saturn/settings.py and do as follow:

INSTALLED_APPS = [
    'polls.apps.PollsConfig',
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
]

Now use makemigrations command to tell Django to store new model changes in migrations folder inside of polls:

$ python manage.py makemigrations polls
Migrations for 'polls':
  polls/migrations/0001_initial.py
    - Create model Choice
    - Create model Question
    - Add field question to choice

Finally use the below command to create the tables:

$ python manage.py migrate
Operations to perform:
  Apply all migrations: admin, auth, contenttypes, polls, sessions
Running migrations:
  Applying polls.0001_initial... OK

migrate is smart and just applies those changes needed, if you are careful enough you can see that a file is created that is called polls.0001_initial. This file is created by our command makemigrations in the previous step.

So we've done 2 steps overall:
1- used makemigrations to create migration files.
2- applied the migration generated in step 1 by using migrate.

#python #django #migrate #models #migrate #makemigrations #django_part5

Django has an admin panel that does lots of tedious works that if you had to create yourself, it wouldn't be an easy t
ask. In this part we try to build the admin panel from ground up.

First of all an admin panel needs an admin user. So create one first:

$ python manage.py createsuperuser
Username (leave blank to use 'fc'): alireza
Email address: a***@***.com
Password:
Password (again):
Superuser created successfully.

Ok after creating the admin user, run the developement server:

$ python manage.py runserver

Now point your URL to http://127.0.0.1:8000/admin/. You should see the login page in the next post. Login and see th
e administrator page of Django.

#python #django #admin #dashboard #createsuperuser #django_part6

#login #django #admin

#django #admin #panel

Django has an admin panel that does lots of tedious works that if you had to create yourself, it wouldn't be an easy task. In this part we try to build the admin panel from ground up.

First of all an admin panel needs an admin user. So create one first:

$ python manage.py createsuperuser
Username (leave blank to use 'fc'): alireza
Email address: a***@***.com
Password:
Password (again):
Superuser created successfully.

Ok after creating the admin user, run the developement server:

$ python manage.py runserver

Now point your URL to http://127.0.0.1:8000/admin/. You should see the login page in the next post. Login and see the administrator page of Django.

#python #django #admin #dashboard #createsuperuser #django_part6


Now to see polls in admin page, you need to register you models. open polls/admin.py:

# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.contrib import admin

from .models import Question
admin.site.register(Question)

Last 2 lines are added to register the Question model as picture below: