Re: [Freeipa-devel] [PATCH] Add interface for baseldap plugins to register additional callbacks.
Pavel Zůna wrote: Rob Crittenden wrote: Pavel Zůna wrote: This is somewhat of a tech-preview patch. It works, but the whole concept might need some more work/thinking done. It adds another way to extend plugins without resorting to the versioning system. Until now, every baseldap command had two callbacks. The pre-callback called before data was passed to python-ldap and the post-callback called after. This patch introduces class methods, that enable the registration of new pre/post callbacks. It supports top level functions as well, so you don't have to touch the original class at all. It works likes this: from ipalib.plugins.user import user_show def test_callback(inst, ldap, dn, attrs_list, *keys, **options): inst.log.info('hello callback world!') attrs_list = ['uid'] # only retrieve the user name return dn user_show.register_pre_callback(test_callback) The original callbacks defined in the class are always called first. Pavel I think I'd like another registration argument, sort of a hint on where you'd like this plugin registered: first or last (defaulting to last). We wouldn't necessarily guarantee where the plugin would get registered but we could easily handle prepending or appending the new registration. The argument is already there, but as you said, it doesn't guarantee a specific order. The "in-class" callback is added when the plugin instance is created and is inserted at the beginning of the list. More callbacks could be theoretically added later before this one, but that probably won't happen. Not sure how complicated we want this to be but we could also add a dependency system, so that if some other callback is registered, then this one comes first (or registration fails), etc. A priority system might be better and easier to implement in this case. I'm also thinking of making the callback signature common for all commands (even though they have different "needs") and adding a context variable callbacks could use to pass data to each other. rob By the way, the approach with class methods and class attributes I'm using is 100% compatible with the versioning system I proposed before. You can do this for example: class user_show(...): VERSION = (1, 0) ... user_show.register_pre_callback(some_callback) user.show_register_pre_callback(some_other_callback) class user_show(user_show): VERSION = (1, 1) ... And the new user_show class will have all the callbacks for the previous version. Isn't that cool? Man, I love python. It's the hackers holy grail. :D Pavel ack, pushed to master ___ Freeipa-devel mailing list Freeipa-devel@redhat.com https://www.redhat.com/mailman/listinfo/freeipa-devel
Re: [Freeipa-devel] [PATCH] Add interface for baseldap plugins to register additional callbacks.
Rob Crittenden wrote: Pavel Zůna wrote: This is somewhat of a tech-preview patch. It works, but the whole concept might need some more work/thinking done. It adds another way to extend plugins without resorting to the versioning system. Until now, every baseldap command had two callbacks. The pre-callback called before data was passed to python-ldap and the post-callback called after. This patch introduces class methods, that enable the registration of new pre/post callbacks. It supports top level functions as well, so you don't have to touch the original class at all. It works likes this: from ipalib.plugins.user import user_show def test_callback(inst, ldap, dn, attrs_list, *keys, **options): inst.log.info('hello callback world!') attrs_list = ['uid'] # only retrieve the user name return dn user_show.register_pre_callback(test_callback) The original callbacks defined in the class are always called first. Pavel I think I'd like another registration argument, sort of a hint on where you'd like this plugin registered: first or last (defaulting to last). We wouldn't necessarily guarantee where the plugin would get registered but we could easily handle prepending or appending the new registration. The argument is already there, but as you said, it doesn't guarantee a specific order. The "in-class" callback is added when the plugin instance is created and is inserted at the beginning of the list. More callbacks could be theoretically added later before this one, but that probably won't happen. Not sure how complicated we want this to be but we could also add a dependency system, so that if some other callback is registered, then this one comes first (or registration fails), etc. A priority system might be better and easier to implement in this case. I'm also thinking of making the callback signature common for all commands (even though they have different "needs") and adding a context variable callbacks could use to pass data to each other. rob By the way, the approach with class methods and class attributes I'm using is 100% compatible with the versioning system I proposed before. You can do this for example: class user_show(...): VERSION = (1, 0) ... user_show.register_pre_callback(some_callback) user.show_register_pre_callback(some_other_callback) class user_show(user_show): VERSION = (1, 1) ... And the new user_show class will have all the callbacks for the previous version. Isn't that cool? Man, I love python. It's the hackers holy grail. :D Pavel ___ Freeipa-devel mailing list Freeipa-devel@redhat.com https://www.redhat.com/mailman/listinfo/freeipa-devel
Re: [Freeipa-devel] [PATCH] Add interface for baseldap plugins to register additional callbacks.
Pavel Zůna wrote: This is somewhat of a tech-preview patch. It works, but the whole concept might need some more work/thinking done. It adds another way to extend plugins without resorting to the versioning system. Until now, every baseldap command had two callbacks. The pre-callback called before data was passed to python-ldap and the post-callback called after. This patch introduces class methods, that enable the registration of new pre/post callbacks. It supports top level functions as well, so you don't have to touch the original class at all. It works likes this: from ipalib.plugins.user import user_show def test_callback(inst, ldap, dn, attrs_list, *keys, **options): inst.log.info('hello callback world!') attrs_list = ['uid'] # only retrieve the user name return dn user_show.register_pre_callback(test_callback) The original callbacks defined in the class are always called first. Pavel I think I'd like another registration argument, sort of a hint on where you'd like this plugin registered: first or last (defaulting to last). We wouldn't necessarily guarantee where the plugin would get registered but we could easily handle prepending or appending the new registration. Not sure how complicated we want this to be but we could also add a dependency system, so that if some other callback is registered, then this one comes first (or registration fails), etc. rob ___ Freeipa-devel mailing list Freeipa-devel@redhat.com https://www.redhat.com/mailman/listinfo/freeipa-devel
Re: [Freeipa-devel] [PATCH] Add interface for baseldap plugins to register additional callbacks.
On 03/04/2010 10:15 AM, Pavel Zůna wrote: This is somewhat of a tech-preview patch. It works, but the whole concept might need some more work/thinking done. It adds another way to extend plugins without resorting to the versioning system. Until now, every baseldap command had two callbacks. The pre-callback called before data was passed to python-ldap and the post-callback called after. This patch introduces class methods, that enable the registration of new pre/post callbacks. It supports top level functions as well, so you don't have to touch the original class at all. It works likes this: from ipalib.plugins.user import user_show def test_callback(inst, ldap, dn, attrs_list, *keys, **options): inst.log.info('hello callback world!') attrs_list = ['uid'] # only retrieve the user name return dn user_show.register_pre_callback(test_callback) The original callbacks defined in the class are always called first. I don't see any problem with this approach, plus it seems advantageous to have a list of callbacks as opposed to a single callback. FWIW this is how some of the frameworks I'm familiar with (e.g. GTK2) work. -- John Dennis Looking to carve out IT costs? www.redhat.com/carveoutcosts/ ___ Freeipa-devel mailing list Freeipa-devel@redhat.com https://www.redhat.com/mailman/listinfo/freeipa-devel
[Freeipa-devel] [PATCH] Add interface for baseldap plugins to register additional callbacks.
This is somewhat of a tech-preview patch. It works, but the whole concept might need some more work/thinking done. It adds another way to extend plugins without resorting to the versioning system. Until now, every baseldap command had two callbacks. The pre-callback called before data was passed to python-ldap and the post-callback called after. This patch introduces class methods, that enable the registration of new pre/post callbacks. It supports top level functions as well, so you don't have to touch the original class at all. It works likes this: from ipalib.plugins.user import user_show def test_callback(inst, ldap, dn, attrs_list, *keys, **options): inst.log.info('hello callback world!') attrs_list = ['uid'] # only retrieve the user name return dn user_show.register_pre_callback(test_callback) The original callbacks defined in the class are always called first. Pavel 0001-Add-interface-for-baseldap-plugins-to-register-addit.patch Description: application/mbox ___ Freeipa-devel mailing list Freeipa-devel@redhat.com https://www.redhat.com/mailman/listinfo/freeipa-devel