Hi Chris, I've been working with Patrick on this charm and I implemented a simple version of support for private repositories. It basically creates a .netrc file with the user name and password for the correct machine. It's not ideal but it did enable me to get code from a private github repo. We need something more robust in the long term but it's a start.
Regarding the concept of running gunicorn on a different machine, this will not be necessary going forward. v2.0 of Juju is meant to support co-location where you could have different services on the same machine (in practice this is already supported in the jitsu package). However, Patrick's idea is to ensure that you can use any WSGI server, whether Apache or gunicorn without having to force one or the other. Everything else you suggest is definitely in the pipe. The main stumbling block at the moment and for which we could do with Django expertise is about the structure of the settings files. Some settings are application specific and should be left alone by Juju, others are environment specific and should be generated by Juju (database config for instance). Patrick solved that problem by separating different config elements in different files but this implies that juju'ised applications would need to follow the same structure. Is that a good idea? Cheers, Bruno On Saturday, 2 March 2013 20:14:19 UTC, Christopher Glass wrote: > > Hi Patrick, > > Great to hear you're interested in writing a Django charm for juju! I have > toyed around with the idea, but never got around to implementing something > good. > I started looking at the current Django charm a little while ago, and > while it works to some extend I think we could make really great things > happen with a little work. > > As far as feedback for your point goes, here are a few points and > suggestion I'd like to add to the discussion: > > - Most of the Django websites will likely live in private git/bzr/whatever > repositories, and so in the workflow you outlined, you need to somehow push > the *private identifier* to the running juju instance. In the "standard" > scenario that means pushing your private ssh key to the instance, so it can > git clone from a private repository on github... I think it's safe to say > that most people will at least frown at the idea :) > Maybe we should instead make this a "push" process? > > - It seems a little strange to me to run gunicorn on another machine. Most > of the Django project I have encountered run Django with gunicorn on the > webservers themselves (add gunicorn to INSTALLED_APPS and then "manage.py > run_gunicorn"). Perhaps we should be a little more opinionated about things > and for the sake of scaling simplicity deploy nginx or apache locally too > (wither with a charm subordinate or at install), so that we can > load-balance to all of the servers easily with any frontend (that means all > webservers would serve static files, which might not be optimal, but we can > refine that later). > > - We should absolutely define a cache relation (redis or memcached). > > Theses points would make the whole workflow look like the following (the > juju syntax might be a little wrong, but please bear with me :) ) > > juju bootstrap > > juju deploy --config my_django_conf.yaml cs:django_server my_django_site > juju deploy cs:postgresql # or mysql,mongodb, etc > juju deploy cs:memcached # or redis if that's still popular > juju deploy cs:haproxy > > juju add-relation my_django_site postgresql > juju add-relation my_django_site memcached > juju add-relation my_django_site haproxy # strictly speaking that's > optional if you have only one django machine > > juju expose haproxy > > # when needed (I hope we all need it someday!) > juju add-unit my_django_site > juju add-unit memcached > juju add-unit postgresql > > So now we would have a running django server with no code. > But if it's a push process, we can implement many of the config changes as > git hooks, which makes the workflow continue with: > > cd my-django-site > git init . # If that's not done already of course > git add . > git commit -m "produciton push yay!" > git remote add production > git+ssh://my_django_site/some_configurable_url.git > git push production master # or of course whatever branch you put in the > config.yaml > > Of course, that requires a non-trivial amount of git triggers to be > written, and we should put some requirements.pip.txt file and > requirements.apt.txt or whatever in the project tree, but I think that's > acceptable. > The whole thing basically follows what many PaaS providers already do, so > I guess most Django developers with some sites in production probably are > familiar with the workflow. > > This would just add the juju coolness to it :) > > Hope this fuels the discussion, > > - Chris > > On Friday, March 1, 2013 8:13:36 PM UTC+1, Patrick wrote: >> >> Hi, >> >> I'm building a Juju based Open Source Paas platform for Django and >> I need your help because it is a hard task to make a PAAS system >> that is flexible enough to deploy any projects and at the same time >> simple to use. >> >> For the ones that don't know Juju, it's a service orchestration software >> compatible with LXC (local), EC2, HPCloud, OpenStack and Baremetal/Maas >> developed by Canonical (the company that makes Ubuntu). >> >> Check out the web site for more details: https://juju.ubuntu.com/ >> >> So quickly, here's how it would works: >> >> After installing Juju and configuring it with for your favourite cloud >> provider you >> will need to create a configuration file in the YAML format named >> my_django_conf.yaml >> in this example:: >> >> my_django_site: >> vcs: git >> repos_url: https://github.com/my_username/my_site.git >> site_secret_key: abcdefgh123456789 >> use_virtualenv: True >> >> Then you will need these commands to bootstrap and launch all the >> servers:: >> >> juju bootstrap >> >> juju deploy --config my_django_conf.yaml my_django_site >> juju deploy postgresql # or mysql,mongodb, etc >> juju deploy gunicorn # Or mod_wsgi, etc >> >> juju add-relation my_django_site postgresql >> juju add-relation my_django_site gunicorn >> >> juju expose gunicorn # Open the tcp port in the firewall >> >> You will end up with 3 servers running. One will be the controller >> and one for each service (django and the database). >> Gunicorn will be a special charm that will be installed on your Django >> server. >> After that, adding a new Django node would be as simple as:: >> >> juju add-unit my_django_site >> >> >> >> As I said, where it gets tricky is how do I make the configuration >> flexible enough >> and at the same time simple. >> >> After looking at what was existing in Django's Paas world, I came with >> this: >> >> 1 - We need a configurable requirements files for both pip and apt-get. >> By default >> it would be looking for package in there files at install time:: >> >> requirements_pip_files: requirements.txt,requirements.pip >> requirements_apt_files: requirements.apt >> >> and we could also configure extra packages by adding variables like this >> in the YAML file:: >> >> additional_distro_packages: vim,emacs,etc >> additional_pip_packages: virtualenvwrapper,celery,South,etc >> >> 2 - I'm suggesting to use separate configurations files in a settings/ >> directory >> so by default it will be injecting configuration in those files:: >> >> settings_database_path: settings/20-engine.py >> settings_static_path: settings/20-static.py >> settings_uploads_path: settings/20-media.py >> settings_cache_path: settings/30-cache.py >> settings_secret_key_path: settings/20-secret.py >> >> I'm suggesting splitting settings because when the configuration is >> modified, >> for some reason, it would be difficult and risky to parse settings.py and >> change only the right thing. >> >> So instead, I would be using topic files rendered with templates. >> So if you would need to do more advanced stuff you could just fork the >> charm >> and modify the templates for your needs. >> >> 3 - Finally, I was thinking adding some options to execute custom scripts >> that >> would run a various time during the deployment. Like after packages >> installation >> ,database configuration and static file configuration:: >> >> post_database_script: >> type: string >> default: | >> #!/bin/sh >> python manage.py syncdb --noinput >> python manage.py migrate --noinput >> post_static_script: >> type: string >> default: | >> #!/bin/sh >> python manage.py collectstatic -v 0 --noinput >> >> Note that this is not making unanimity so far. >> There is several reasons that makes the scripts approach tricky: >> >> * You don't want to execute these scripts every time a little detail >> change. >> * You might need the database configuration to be ready for some script. >> * You could be not using south >> * You might want to import some initial data and maybe only once at >> install time. >> * You could want to compress static files after running collectstatic >> * etc >> >> An other idea could be to use a Fabric plug-in that use Juju's database >> to connect >> to the machines and run commands like this for example:: >> >> fab -R my_django_site python manage.py pull >> >> would pull the latest version of the site and reload the application on >> every >> deployed Django machines. >> >> The bottom line here is that it's not simple to find out what a standard >> Django deployment (and is maintenance) looks like. >> >> That being said, I'm really looking forwards for you comments and >> suggestions. >> >> Patrick >> > -- You received this message because you are subscribed to the Google Groups "Django users" group. 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