I have my existing Django web application that uses a MySQLDB without memcaching.
I would like to implement memcaching to improve the responsiveness of this site. I see the instructions here.
However, these instructions leave me with some unanswered question(s). Is this all I need to do to get memcache working after I setup the memcached server? Or do I need to alter any of my code outside of settings.py? Does Django nicely handle all the memcaching operations behind the scenes for me whenever models are read or written? (If so, that's very cool!) How can I see what improvement the memcaching is having on the number of DB accesses?
What you've done is just a set up of a Cache Backend.
In order to benefit from caching you need to find the places where it is appropriate and would have a positive impact on performance: your views, templates..you can cache the whole views, templates, template fragments etc.
If you want some automation to help you, take a look at Johnny Cache package:
Johnny Cache is a caching framework for django applications. It works
with the django caching abstraction, but was developed specifically
with the use of memcached in mind. Its main feature is a patch on
Django’s ORM that automatically caches all reads in a consistent
manner.
Or django-cache-machine package:
Cache Machine provides automatic caching and invalidation for Django
models through the ORM.
There is also an interesting project called django-cacheops that is aiming to improve Django ORM caching, but it uses Redis backend.
Also, django_debug_toolbars caching panel can help you in the future.
Note that django querysets have a built-in internal cache, but it has nothing to do with a cache framework.
Further reading:
Using Django querysets effectively
Caching and QuerySets
Related
I want to replace the default Django Admin templates with a completely revamped bootstrap version. The data in the Dashboard should be populated from the DB. How do I work with templated files ? Which files should be overriden ? In which template tag does HTML code go ?
From django docs on admin:
The admin’s recommended use is limited to an organization’s internal management tool. It’s not intended for building your entire front end around.
It's possible to change templates to do what you want, but that will be very complex - you have to basically rewrite most of the templates, get to know how it is working internally and probably change that too to your own design (after all, you are going to show specific details, like charts, data and so).
You will faster to achieve results if you going to build your own app, that will work exactly like you need without multiple fixes. Does it have to use js frameworks depends entirely on your requirements. Usually they are much more simple for admin backends, that are going to be used by owners, not clients. Anyway, if you don't have experience or knowledge in this, you will probably better off with just plain static django templates.
Django admin is just a same app as the ones you build, so limitations will be the same. Security wise, it doesn't offer much that you can't do yourself - make sure you have permissions set in models/views. Read more about security in django.
From functionality point of view, django admin just comes with CRUD access to your models, which can be done quite quickly. Once you past that, you will have much easier time adding functionality to your own app instead of overriding django admin.
Overall, I advise you to build your app for CMS-like admin panel. JS frameworks is neat, but that require burden of multiple additional tests (with api mocks), constant swapping between adding api / writing a component and much higher time consumption overall.
I am developing an application in which user can add, delete , retrieve or update the transactions. I want to store transactions data in the redis cache based storage to improve the performance, what steps should I follow to achieve this?
I highly recommend you to check out cacheops django package.
https://github.com/Suor/django-cacheops
It has build in functionality for automatic/manual query/view/template sections/function caching as well as get/set primitives for simple cache by key.
There is a Django Redis package that might help you.
If you want to automatically cache all querysets (e.g. on SELECT ... operations) you may also use this package with django-redis as a cache backend. Both of above will work with Django Rest Framework.
I have two apps that both access the same database. The first has clients connecting via TCP and writes to the db using SQLAlchemy. The second is a more typical webapp using Django. Both have read/write requirements.
I would like to unify the database access layer, but picking just SQLAlchemy or just Django is unattractive because:
I would like to use django auth, permissions, and maybe third party plugins, which require the Django ORM (correct me if I'm wrong).
For the first app, using SQLAlchemy (so far) is much simpler than trying to use the Django ORM outside of a Django app - it is a TCP/IP server app, not a HTTP/web app.
Are there any problems with mixing these two ORMs on the same database?
In which system (Django, SQLA) should I create the models, vs using some kind of introspection such as Django inspectdb?
Firstly - it's not very hard to use Django ORM outside a manage.py, WSGI handlers and other HTTP related stuff. You can use it any python script, but it needs some initialization (example).
Secondly - SQLA is a very powerfull tool and it's able to do stuff which is very hard to achive in Django ORM (like genuine polymorphism and polymorphic queries). If I had to choose, I'd personally choose to use Django ORM as a platform to create models, then manually map them in SQLA since it is much more flexibile and hopefully will be able to adopt. Which may not work in the opposite case.
Finally, since you can use Django ORM on both sides, and you just have to use a Django ORM because of the plugins, I suggest to abandon the SQLA. It's a powerfull tool, but also rather complicated. Having two different ORMs operating on one database may result in unexpected problems in the future and increases the complexity of your app, so it'll be harder to maintenance.
I have a Django web front-end that consumes data from a REST API backend.
Even the users are made and created on the backend.
My Problem :
How to use 3rd party apps within this system, that heavily depend on django models/ORM ?
Is there something that can provide some bridge between the REST API resources and the ORM?
How can this problem be dealt with ?
Update
DRY principal seems to be failing in this situation.
Probably things have changed since this question has been originally posted. Now there are a couple of interesting related questions on StackOverflow about this topic.
To code yourself a solution as explained in this answer, you can create an external service layer (aka services.py) and write there the logic to access the external resources. Your views will consume this layer, and make the proper actions. There are other questions that provide help on how to pass information from the original request received by the django-view to the external service like this or this
There is also a django app that takes this situation into account as explained in this answer. django-roa uses the Resource Oriented Architecture paradigm to solve this.
I'm facing a similar obstacle with a new ecommerce project.
The project is a front end to a full-fledged store management software (CMS+ERP+CRM). It needs to use the master product database, but have its own entries for product reviews, ratings and so on.
The initial thought was to make a cached copy of the master database. The website will benefit from fast loading times for the cached items, but the implementation is not trivial.
After some considerations, the selected approach was updating the website's DB from the management program. This way the website's copy will always be correct, and most of the implementation doesn't need to worry about REST services (it'll still be used for user registration, shipment tracking etc.)
In your case, where you can't have the service update your own database remotely, you need to come up with a mechanism that allows you to refer to REST recourses like regular models, and that caches them in the background.
Important note: research for a way to make sure the cache is always correct (non-dirty)...
I'm not sure I completely understand your question or requirements. The way I am reading it, you have a primary back-end which is basically a black-box, and you want to use some 3rd-party apps in your project which use the Django ORM.
I am unclear as to why there would be a need for being able to have a two-way synchronization between the two data-stores. The users of your project would be returned data from your primary back-end, and from the project's ORM.
Since you are concerned about saving the "ORM" data in your primary back-end, maybe you would consider creating a Transaction Middleware that would fire any time ORM data gets updated, which could serialize the structure being saved and transmit it to your REST API. This REST API, I assume, is able to accept arbitrary data structures?
You'll probably at least want to use some form of middleware, and maybe a utility module/class to help form the "bridge".
I'm building my first python app on app-engine and wondering if I should use Django or not.
What are the strong points of each? If you have references that support your answer, please post them. Maybe we can make a wiki out of this question.
Aral Balkan wrote a really nice piece addressing this very question. Its a year or so old, so take it with a grain of salt - I think that a lot more emphasis should be put on the awesomeness of django's Object-Relational-Model. Basically, IMHO, it all comes down to whether or not you have a preference for using DJango's object model (which I happen to).
If it's not a small project, I try to use Django. You can use the App Engine Patch (http://code.google.com/p/app-engine-patch/). However, the ORM cannot use Django's meaning your models.py will still be using GAE's Datastore.
One of the advantages of using Django on GAE is session management. GAE does not have a built-in session.
You won't be able to using most Django 3rd-party apps though especially those with model changes. I had to build my own tagging app for GAE.