I've written a simple Django Q&A forum app and deployed it on Heroku. The local version of the site works fine. However, the production version does not store the questions, answers etc. for more than a few hours.
I decided to stick with sqlite3 that comes with Django. I don't expect a lot of traffic to the site so I decided it would be worth it to keep the development database for now.
site: http://immense-plateau-35286.herokuapp.com
I've tried a few solutions from the DB setup page on Heroku, but have not had any success so far.
Any idea what this might be?
Heroku's filesystem is ephemeral. Anything you write to it will be lost anytime your dyno restarts, which happens frequently. Since SQLite stores its data in a file on the filesystem it isn't a good choice on Heroku.
Instead, consider using one of the many client-server data stores that Heroku supports. Its PostgreSQL offering works reasonably well.
Related
So I recently finished my python project, grabbing values from an API and put it into my website.
Now I have no clue how I actually start the website (finding a host) and making it accessible to other people, I thought turning to here might find the solution.
I have done a good amount of research, tried "pythonanywhere" and "google app engine" but seem to not really find a solution.
I was hoping to be able to use "hostinger" as a host, as they have a good price and a good host. Contacted them but they said that they couldn't, though I could upload it to a VPS (which they have). Would it work for me to upload my files to this VPS and therefor get it to a website? or should I use another host?
I just deployed my first app and used Heroku. I'm very happy with it so far and it was fairly straight forward to set up. It does require a basic git understanding but was not hard to learn
A VPS would work, but you'll need to understand basic linux server admin to get things setup properly.
Sounds like you don't have any experience with server admin, so something like App Engine would be great for you. There are a ton of tutorials on the internet for deploying flask to GAE.
I'm setting up my new website, but the web have some problem. It gives me an OperationalError at /topics/ and no such table: toms_topic.
This is a Heroku web dyno, running Django2.2 and Python 3.7.3.
I have executed
python manage.py migrate
and when I go to the db.sqlite I find the table toms_topic exists.
And everybody can goto the website https://cblingh.herokuapp.com for take more information
My last website haven't this problem,maybe I add image this time,and the image is foreignkey with topic.But i not sure it's the key of this problem yet.The topic have two foreignkey (entry,image).
You can't use SQLite on Heroku. Its filesystem is dyno-local and ephemeral. Any changes you make to it will be lost whenever your dyno restarts. This happens frequently (at least once per day).
Heroku offers good support for client-server databases. If you want to use Heroku you'll have to switch to one. Their own PostgreSQL service works well and is available out of the box. If you prefer other databases feel free to browse the data store addons.
I am developing a Django application in Atom locally, and then on pythonanywhere, when I'm ready, I'm doing a GIT PUSH command after syncing those changes to GITHUB. The problem is, at some point, those changes which were pushed through from my local development env have overwritten all my live users with just the local dummy users I've been using for testing and development.
Basically, I'm testing the login and registration system locally, logging in and registering with lots of dumb emails. Once I was happy it was working, I synced the Django code I'd changed to GITHUB (with the desktop app) and then did a GIT PUSH command on a PythonAnywhere (my server) console. The sqlite DB is included in those updates/sync - is that correct? Or should it just be totally ignored?
I just realised, that one (perhaps all?) pushes have overwritten my sqlite DB, and there were perhaps 30 or so actual users who had signed up on the website whose data is no longer registered on the site. I managed to find a trace of them in the Django Admin logs, and I've found the version history of the Sqlite DB on GITHUB, but my question is - how do I avoid this happening?
What is the workflow to avoid this situation in the future? And is there a command I can run in shell to get those users back into my 'live' database from the backedup SQlite file?
I know this is a simple question, but I'm new to development and I'm slowly getting there with troubleshooting the code, but versioning, GIT, and workflow are tricky things to get my head around.
Is there a way to use Sqlite3 with Django on Heroku?
The cedar stack's filesystem is not readonly.
However, you still mustn't store any data on it because the filesystem is ephemeral.
Any time your application restarts, whatever you had written to your application's filesystem disappears forever.
Any time you add a dyno, the two dynos each have their own ephemeral system; any data stored by one dyno to its ephemeral filesystem is not available to the other dyno or to any additional dynos you may add later.
Sqlite3 writes data to the local filesystem. You cannot use Sqlite3 with Heroku.
Heroku provides a default PostgreSQL installation, which Heroku manages. You can use that.
You can also use any third-party-managed cloud database system, such as Amazon RDS' or Xeround's MySQL, MongoHQ's or MongoLab's MongoDB, or Cloudant's CouchDB - all of which are available as Heroku addons.
I'm not sure when this answer became out of date, but as of at least 21 Nov 2013, sqlite3 CAN be used on heroku: https://devcenter.heroku.com/articles/sqlite3
It will work fine if you're just doing a tiny demo app, e.g. running 1 dyno and don't care that the database gets wiped at least once every 24 hours. If not, the heroku help article suggests migrating to Postgres.
Make sure the .db file is in your git directory somewhere and not in /tmp/ though, as it would be if for instance you were following the Flask tutorial app, flaskr.
I am developping a django app on Windows, SQLite and the django dev server . I have deployed it to my host server which is running Linux, Apache, FastCgi, MySQL.
Unfortunately, I have an error returned by the server on the prod while everything ok on the dev machine. I've asked my provider for a pre-production solution in order to be able to debug and understand the problem.
Anyway, what are according to you the most likely errors that can happen when moving a django app from dev to prod?
Best
Update: I think that a pre-prod is the best way to address this kind of problem. But I would like to build a check list of what must be done before to put in production.
Thanks for the very valuable answers that I received until now :)
Update: FYI, I 've implemented the preprod server and the email notification as suggested by shanyu and I can see that the error comes from the smart_if templatetag that I am using on this new version. Any trick with template tags?
Update: I think I've fixed the pb which was caused I think by the Filezilla FTP sending. I was using the "replace if newer" option which I guess is causing some unexpected results. Using the "replace all" option fix the issue. However, it was an opportunity for me to learn more about deployment. Thansk for your answers.
Problems I typically have include:
Misconfigured productions settings, whether in my production localsettings.py, wsgi/cgi, or apache site files in /etc/sites-available
Database differences. I use South for migrations and have run into some subtle issues when performing my migration on PostgreSQL when it worked smoothly in sqlite.
Static file hosting since I cheat and use the Django server in development
Permissions, both on the file system and within the database
Rare, but possible, network issues preventing me from getting my dependencies, whether on PyPi or some 3rd party site
Ways that I have mitigated these issues:
Use the same database in production and development (in your case, MySQL everywhere)
I've found it is useful to have a "test" environment which mimics production in every way possible (it can be on lower end hardware, or even the same machine). This way, if there are any issues in this "production-like" enivornment, I can solve them without taking my production server offline.
Script everything for repeatable deployments. I use fabric, but zc.buildout or Paver would also work. These tools help reduce typos while deploying and reduce the time to deploy my app.
Use version control (mercurial, git, subversion) and a schema migration tool (like South), so if something does go wrong when you deploy to production, you have the possibility of backing out the changes and allowing production to run on the old code with the old database schema.
I haven't set up an "egg proxy" yet, but I am considering it, to avoid issues when downloading dependencies.
I've found pip's freezing dependencies to be useful, in case a new, incompatible change to a library occurred since I downloaded it initially
Use a web testing framework like Windmill or Selenium to test my application in my "test" environment, so that I can get a lot of test coverage of my system very quickly.
Regarding your case, I can think of 2 simple things that may help you:
You can enable Django to send messages when exceptions occur giving details about them. Look at here for details.
You'll be better off if you set up a test environment on the prod server (say, test.example.com) so that you can check if things will go smoothly or not before you deploy the app.
I believe these were the podcasts I listened to recently (from Pycon 2009):
Locate Django in the Real World (PyCon 2009):
http://advocacy.python.org/podcasts/pycon.rss
Parts 1 to 3
Very good introduction to designing your apps for deployment, in particular for reuse and redeployment.
Regs.