Hi Sheila, Thank you for all your great ideas, for some backgrounds checkout a discussion about the future of the charm in this thread:
http://comments.gmane.org/gmane.linux.ubuntu.juju.user/1649 I'm working to rewrite the charm using Ansible so I don't think I'll add new features to the current "pure python" charm. But all your comments are really welcome for helping building the new charm. 2015-01-09 10:29 GMT-05:00 sheila miguez <she...@pobox.com>: > I need to have upgrade functionality for this charm. I'm not experienced > with writing hooks, so I want to check my assumptions and ask questions. > > Here begins the wall of text. > > During install, configure_and_install[1] is called in the install hook to > install Django and, optionally, South. > > configure_and_install is handling concerns that I think would be better to > split out. > > Here is the current logic: > * if the user specifies a ppa, it will add the ppa > * if the user specifies a key, it will add the key > * if the method is somehow called with an empty string, it bails > * otherwise it defaults to pip > > I think it would be better to break this up. > > Adding apt repositories and keys should be done separately. Config items > could be added for a ppa list and a key list. Install could check for those > and add them regardless of any django or south concerns. > I agree with you. The idea will be to create an "aptkit" ansible role that could be reuse as many time that you need in the charm's playbook see: http://bazaar.launchpad.net/~patrick-hetu/charms/precise/python-django/ansible_reboot/view/head:/playbooks/roles/aptkit/defaults/main.yml or you could use "pure" ansible modules in the in the pre_tasks section: http://docs.ansible.com/apt_repository_module.html > > Django and South versions/distro/whatever would proceed separately. > The idea here was to create a "django-app" ansible role that handle is dependencies independently of the other apps: http://bazaar.launchpad.net/~patrick-hetu/charms/precise/python-django/ansible_reboot/view/head:/playbooks/roles/django-app/tasks/main.yml > This makes upgrade simpler, I think. Upgrade would have similar steps to > install, but I have a question about idempotence when adding apt > repositories and keys. Are those idempotent? If not, then refactoring them > out of that method makes it easier to idempotently handle Django and South > dependencies. > They should be idempotent because apt-add-repository, pip, apt-get are idempotent and in the pure-python charm they are checked every time configuration change. So changing the ppa should upgrade the packages. > > Now on to general plans for upgrade hook. It needs these to be added, but > I want to know if my assumptions are mistaken: > * ability to pull new src > * ability to upgrade django and south > * ability re-inject settings > > I think those actions could be done via configuration changes and not necessarily via an explicit upgrade but drawing the line is tricky. I'm trying to build the new charm in a way that it would be easier to be integrated in a continuous integration workflow but I'm really not sure how thing would work. > And one general observation I have -- if I could remove some of the > options this charm allows, it would be easier to deal with. e.g. not give > many options for how packages are installed. Force people to do it only one > way. Pick a recommended practice and stick with it. I recommend taking a > look at what audryr and pydanny suggest, but ultimately, whatever devops > people decide to want, I will roll with it. but pick one way. > I don't think there is a clear recommended practice that I can stick with. > To sum up, if you reached this far, I'd really like for my assumptions to > be checked and corrected. Help! > > Ps. as a side note, you can see some of the tiny incremental changes I'm > thinking about in my branch[2]. I need to have the ability to install a > project from a tarball due to lack of access. I'm not sure I will > ultimately request any merge for tarball functionality as it is really > janky. but it's what I have to work with based on what we've been doing at > work. > Yeah, I can really see how this feature would be useful. Also, Micheal is working on something similar: https://github.com/absoludity/charm-ansible-roles/tree/master/wsgi-app Thanks again and sry to have took so long to answer. Patrick
-- Juju mailing list Juju@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/juju
