Category: DevOps

  • Django: how to run backgroung tasks in parallel and deferred processing (background tasks) thanks to celery

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    Head of celery, sold as a vegetable. Usually only the stalks are eaten. (Photo credit: Wikipedia) I am implementing a web app with Django. In my App, a user submits tasks, and receives an email when they are done.  The tasks can take a few minutes to complete, and an end-user can submit several tasks…

  • Discovering Django on Debian – part 3: creating the models (example of a text processing web app)

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    Django logo (Photo credit: Wikipedia) Have a look to the first two parts of this serie of Django tutorials, to see how to install virtualenv and django, and how to configure django with a mysql database. First a bit of vocabulary. We have seen that Django creates a package that contains the configuration of our…

  • How to install google chrome on debian?

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    Debian OpenLogo (Photo credit: Wikipedia) Logo used from the start of the Chrome project until March 2011 (Photo credit: Wikipedia) You can install Google chrome on Debian in only three steps: (1) go to https://www.google.com/intl/en/chrome/browser/ and download the appropriate .deb package (2)  Install it sudo dpkg -i ~/google-chrome-stable_current_amd64.deb (3)Solve dependency issues sudo apt-get -f install…

  • A Django tutorial on Debian – part 5: implementing the frontend

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    Django logo (Photo credit: Wikipedia) In Django the essential part of any project consists in defining the data structures. Then, implementing a webpage to a web application consists in nothing more than providing a “view” on these data structures. We will define such view for our web application in the file textModif/views.py from django.http import…

  • A Django tutorial on Debian – part 4: creating the web administration portal

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    Django logo (Photo credit: Wikipedia) .Django creates automatically a web admin portal for our web app. We just have to edit the settings.py file and to uncomment “django.contrib.admin” in the INSTALLED_APPS setting. # Uncomment the next line to enable the admin: ‘django.contrib.admin’, # Uncomment the next line to enable admin documentation: ‘django.contrib.admindocs’,    We need…

  • How to solve the duplicate entry errors in Django

    Sometimes when saving an object in Django, one faces the following kind of errors: File “/home/alan/virtualenv_1/lib/python2.6/site-packages/MySQLdb/connections.py”, line 36, in defaulterrorhandler raise errorclass, errorvalueIntegrityError: (1062, “Duplicate entry ’18’ for key ‘PRIMARY'”)   To solve such error, the easiest way is often to just delete the object that was previously stored, with the following command: TextModification.objects.filter(id=18).delete()  …