heroku migration

UPDATE: I setup a template project for django project bootstrapping on heroku; take a look and fork it.

Finally got my original site up. Phew...

Today I continue my migration work. The major problem is, again, serving static files. I am not sure if other web frameworks have such problem in serving static files too, but this one really bugs me, every time.

Anyway, searched a lot, not much helpful, stuck with it for quite some time. During this I find a weird question though, that people use different project structure for django. As default, when you run startproject command, you will create a project like this:

project_name:
|-- manage.py
|-- project_name:
    |-- __init__.py
    |-- settings.py
    |-- wsgi.py
    |-- urls.py

It creates a subdir inside your project dir with the same name to store configuration files. Somehow people tend to move them up to the project dir and delete the subdir. I am not sure why they are doing this but in my opinion it would be better to stay as the original because thus you could separate project configuration files with other miscellaneous ones like Procfile. Actually some posts I find about how to serve static files use such "flat" structure. This actually leads to a difference in settings.py. So in the file we have to indicate the path for static files, templates, media so that django knows where to find those files. You could of course hard code them if you know every bit of the path for your files, but an easier way would be using a built-in python module os:

import os

SITE_ROOT = os.path.dirname(os.path.realpath(__file__))

STATICFILES_DIRS = (
    ...
    os.path.join(SITE_ROOT, '../static'),
)

TEMPLATE_DIRS = (
    ....
    os.path.join(SITE_ROOT, '../templates')
)

The method above would return the absolute path for this particular file, then we could append specific folder name for different use. This is especially useful when you are doing web dev, because it is likely that you will have at least two environment, development and production. To hardcode for two different environment would be tedious. Now just let the script do the job.

Anyway, you notice the .. before each folder name, because I use the default project structure, my static and templates folders are outside of the folder that contains settings.py. In order to locate them correctly, I have to first go up one level in the dir, then find those folders.

The project structure is not a trivial thing because it will get messy if you have a big project with multiple apps and possibly many external apps. I also find some great tutorials about complex project structure; might need them some day.

Anyway, I keep this original structure, and find a great post about using this structure and Amazon S3 to serve static files for django project in Heroku. It is step-by-step tutorial and most important it works (at least for me). Using S3 is surprisingly simple; now I know why django users all like it. When you setup the environment, every time you add new static files, you use django command collectstatic locally, which will automatically upload new ones to your S3 bucket and serve for your heroku app. Also it will collect admin static files for you as long as you keep them in a child folder admin in your static folder.

After solving static file issue, things get faster. I copy some codes, move some files. Then, I got to say, after shutting down my site for several days, it is good to see it's back live. I mean, I know there is few people would accidentally stumble across it, but for me it is a place I build from the scratch. Now I have this free power of heroku; let's build more.