The main problem with having a hook that just fires instead of the others is that you end up firing a hook a whole bunch of times where it essentially "does nothing" because it is still waiting for some other hook for it to actually be ready. The "something-changed" proposal essentially colapses the 10 calls to various hooks into a single firing.
William has thought much more about it, so I'd like him to fill in any details I've missed. John =:-> On Sun, Aug 17, 2014 at 1:59 PM, Nate Finch <[email protected]> wrote: > That's an interesting document, but I feel like it doesn't really explain > the problem it's trying to solve. > > Why does a single entry point cause a lot of boilerplate (I presume he > means code boilerplate)? Isn't it just a switch on the name of the hook? > What does it mean "when a new hook is introduced"? Doesn't the charm > define what hooks it has? And wouldn't the aforementioned switch mean that > any new hook (whatever that means) would be ignored the same way it would > if the hook file wasn't there? > > Can someone explain to me what exactly the problem is? > > > On Sun, Aug 17, 2014 at 1:30 AM, John Meinel <[email protected]> > wrote: > >> I'd just like to point out that William has thought long and hard about >> this problem, and what semantics make the most sense (does it get called >> for any hook, does it always get called, does it only get called when the >> hook doesn't exist, etc). >> I feel like had some really good decisions on it: >> https://docs.google.com/a/canonical.com/document/d/1V5G6v6WgSoNupCYcRmkPrFKvbfTGjd4DCUZkyUIpLcs/edit# >> >> default-hook sounds (IMO) like it may run into problems where we do logic >> based on whether a hook exists or not. There are hooks being designed like >> leader-election and address-changed that might have side effects, and >> default-hook should (probably?) not get called for those. >> >> I'd just like us to make sure that we actually think about (and document) >> what hooks will fall into this, and make sure that it always makes sense to >> rebuild the world on every possible hook (which is how charm writers will >> be implementing default-hook, IMO). >> >> John >> =:-> >> >> >> >> On Sat, Aug 16, 2014 at 1:02 AM, Aaron Bentley < >> [email protected]> wrote: >> >>> -----BEGIN PGP SIGNED MESSAGE----- >>> Hash: SHA1 >>> >>> On 14-08-15 04:36 PM, Nate Finch wrote: >>> > There's new hook in town: default-hook. If it exists and a hook >>> > gets called that doesn't have a corresponding hook file, >>> > default-hook gets called with the name of the original hook as its >>> > first argument (arg[1]). >>> > >>> > That's it. >>> >>> Nice! Thank you. >>> >>> Aaron >>> -----BEGIN PGP SIGNATURE----- >>> Version: GnuPG v1 >>> >>> iQEcBAEBAgAGBQJT7nVvAAoJEK84cMOcf+9h90UH/RMVabfJp4Ynkueh5XQiS6mD >>> TPWwY0FVHfpAWEIbnQTQpnmkhMzSOKIFy0fkkXkEx4jSUt6I+iNYXdu8T77mA38G >>> 7IZ7HAi+dAzRCrGTIZHsextrs5VpxhdzFJYOxL+TN5VUWYt+U+awSPFn0MlUZfAC >>> 5aUuV3p3KjlHByLNT7ob3eMzR2mwylP+AS/9UgiojbUOahlff/9y83dYqkCDYzih >>> C2rlwf0Wal12svu70ifggGKWcnF/eiwSm4TQjJsfMdCfw0gSg4ICgmIbWQ78OytJ >>> AM4UBk1/Ue94dUm3YP+lcgAqJCC9GW5HksCFN74Qr+4xcnuqYoCJJxpU5fBOTls= >>> =5YwW >>> -----END PGP SIGNATURE----- >>> >>> -- >>> Juju-dev mailing list >>> [email protected] >>> Modify settings or unsubscribe at: >>> https://lists.ubuntu.com/mailman/listinfo/juju-dev >>> >> >> >> -- >> Juju-dev mailing list >> [email protected] >> Modify settings or unsubscribe at: >> https://lists.ubuntu.com/mailman/listinfo/juju-dev >> >> >
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