Re: Proposal: Change repository's UUID over RA layer
On Sun, Aug 1, 2010 at 1:17 AM, Ramkumar Ramachandra artag...@gmail.com wrote: Hi, I've found that I need the functionality to change a repository's UUID over the RA layer in 'svnrdump load' (see my recently committed tests to see why). I initially planned to put this off until functionality until someone thinks I'm capable of handling this and gets me commit access to libsvn_ra. However, Daniel asked me not to expect this and start working on a branch instead after notifying the list- I've therefore started a new ra-uuid branch for this (see r981164). Expect to see some commits soon :) It looks like this idea has been discussed, but probably won't go forward. It's probably time to remove the branch. -Hyrum
Re: Proposal: Change repository's UUID over RA layer
Hi Hyrum, Hyrum K. Wright writes: On Sun, Aug 1, 2010 at 1:17 AM, Ramkumar Ramachandra artag...@gmail.com wrote: Hi, I've found that I need the functionality to change a repository's UUID over the RA layer in 'svnrdump load' (see my recently committed tests to see why). I initially planned to put this off until functionality until someone thinks I'm capable of handling this and gets me commit access to libsvn_ra. However, Daniel asked me not to expect this and start working on a branch instead after notifying the list- I've therefore started a new ra-uuid branch for this (see r981164). Expect to see some commits soon :) It looks like this idea has been discussed, but probably won't go forward. It's probably time to remove the branch. Indeed. Thanks for the reminder. Branch removed in r986566. -- Ram
Re: Proposal: Change repository's UUID over RA layer
Hi Daniel, Daniel Shahaf writes: The implementation should be trivial (over ra_local and ra_svn; probably over ra_dav too but I don't know that one as well). But what about authz concerns? Do you want to allow any authenticated user to change the repository UUID? No, this doesn't make sense. Do you want UUID changing to be disallowed by default (unless the server admin took an explicit action)? Yeah. Maybe something like the pre-revprop-change hook? -- Ram
Re: Proposal: Change repository's UUID over RA layer
Ramkumar Ramachandra wrote on Fri, Aug 06, 2010 at 13:40:17 +0530: Hi Daniel, Daniel Shahaf writes: The implementation should be trivial (over ra_local and ra_svn; probably over ra_dav too but I don't know that one as well). But what about authz concerns? Do you want to allow any authenticated user to change the repository UUID? No, this doesn't make sense. Right. So when *would* a UUID change be permitted? When the hook says yes? Or do you want to extend the existing (read/write/none) authz schemes? Do you want UUID changing to be disallowed by default (unless the server admin took an explicit action)? Yeah. Maybe something like the pre-revprop-change hook? Yes, a pre-uuid-change hook (and disallowing a UUID change unless it exists) is one option. But that means the logic lives in libsvn_repos, so you have to think how 'svnadmin setuuid' would interact with it... Daniel -- Ram
Re: Proposal: Change repository's UUID over RA layer
On 08/06/2010 04:30 AM, Daniel Shahaf wrote: Yes, a pre-uuid-change hook (and disallowing a UUID change unless it exists) is one option. But that means the logic lives in libsvn_repos, so you have to think how 'svnadmin setuuid' would interact with it... We just follow the pattern that already exists. By default, 'svnadmin setuuid' would bypass the hooks. (In generally, I think it is assumed that anyone who can run 'svnadmin' on a repository directly can also modify its hooks.) And then we add --use-pre-uuid-change-hook and --use-post-uuid-change-hook options. See 'svnadmin setrevprop' / svn_repos_fs_change_rev_prop3() and 'svnadmin load' / svn_repos_load_fs3() for prior art. -- C. Michael Pilato cmpil...@collab.net CollabNet www.collab.net Distributed Development On Demand signature.asc Description: OpenPGP digital signature
Re: Proposal: Change repository's UUID over RA layer
Back up here. Why would an admin install a hook to allow changing a UUID? Why would a UUID be allowed to change over time? If a UUID is supposed to be changed, then why wouldn't that admin just do it himself? Why does this have to be allowed remotely? I'm sorry, but this whole feature just seems misguided. The UUID is supposed to be stable and unchanging. We use it to determine what repository we're talking to. It isn't supposed to change from one day to the next. -g On Fri, Aug 6, 2010 at 09:02, C. Michael Pilato cmpil...@collab.net wrote: On 08/06/2010 04:30 AM, Daniel Shahaf wrote: Yes, a pre-uuid-change hook (and disallowing a UUID change unless it exists) is one option. But that means the logic lives in libsvn_repos, so you have to think how 'svnadmin setuuid' would interact with it... We just follow the pattern that already exists. By default, 'svnadmin setuuid' would bypass the hooks. (In generally, I think it is assumed that anyone who can run 'svnadmin' on a repository directly can also modify its hooks.) And then we add --use-pre-uuid-change-hook and --use-post-uuid-change-hook options. See 'svnadmin setrevprop' / svn_repos_fs_change_rev_prop3() and 'svnadmin load' / svn_repos_load_fs3() for prior art. -- C. Michael Pilato cmpil...@collab.net CollabNet www.collab.net Distributed Development On Demand
Re: Proposal: Change repository's UUID over RA layer
I have to agree. While it may make sense to be able create a dumpfile of a remote repository, I'm not so sure that /loading/ a dumpfile remotely is sensible. And it's the load that potentially requires a UUID change. -- Brane On 06.08.2010 16:03, Greg Stein wrote: Back up here. Why would an admin install a hook to allow changing a UUID? Why would a UUID be allowed to change over time? If a UUID is supposed to be changed, then why wouldn't that admin just do it himself? Why does this have to be allowed remotely? I'm sorry, but this whole feature just seems misguided. The UUID is supposed to be stable and unchanging. We use it to determine what repository we're talking to. It isn't supposed to change from one day to the next. -g On Fri, Aug 6, 2010 at 09:02, C. Michael Pilato cmpil...@collab.net wrote: On 08/06/2010 04:30 AM, Daniel Shahaf wrote: Yes, a pre-uuid-change hook (and disallowing a UUID change unless it exists) is one option. But that means the logic lives in libsvn_repos, so you have to think how 'svnadmin setuuid' would interact with it... We just follow the pattern that already exists. By default, 'svnadmin setuuid' would bypass the hooks. (In generally, I think it is assumed that anyone who can run 'svnadmin' on a repository directly can also modify its hooks.) And then we add --use-pre-uuid-change-hook and --use-post-uuid-change-hook options. See 'svnadmin setrevprop' / svn_repos_fs_change_rev_prop3() and 'svnadmin load' / svn_repos_load_fs3() for prior art. -- C. Michael Pilato cmpil...@collab.net CollabNet www.collab.net Distributed Development On Demand
Re: Proposal: Change repository's UUID over RA layer
Hi Greg, Greg Stein writes: Why would an admin install a hook to allow changing a UUID? Why would a UUID be allowed to change over time? If a UUID is supposed to be changed, then why wouldn't that admin just do it himself? Why does this have to be allowed remotely? Agreed- this feature has a very narrow usecase. Anyway, since I started the thread, let me explain the motivation for this feature. It derives from `svnrdump` -- Anybody without administrative priviliges can actually mirror a complete Subversion repository using `svnrdump dump | svnrdump load` quite efficiently. Let's say some sponsor wants to provide a mirroring service- with the proposed feature the person will simply have to create a blank repository and enable pre-revprop-change/ pre-uuid-change on and wait for someone to load the content into that repository. After the intial mirroring is done, he can always turn off the pre-uuid-change. It's probably a dangerous feature, and I don't know if it's worth the trouble. -- Ram
Re: Proposal: Change repository's UUID over RA layer
On Fri, Aug 6, 2010 at 9:24 AM, Greg Stein gst...@gmail.com wrote: On Fri, Aug 6, 2010 at 10:15, Ramkumar Ramachandra artag...@gmail.com wrote: Hi Greg, Greg Stein writes: Why would an admin install a hook to allow changing a UUID? Why would a UUID be allowed to change over time? If a UUID is supposed to be changed, then why wouldn't that admin just do it himself? Why does this have to be allowed remotely? Agreed- this feature has a very narrow usecase. Anyway, since I started the thread, let me explain the motivation for this feature. It derives from `svnrdump` -- Anybody without administrative priviliges can actually mirror a complete Subversion repository using `svnrdump dump | svnrdump load` quite efficiently. Let's say some sponsor wants to provide a mirroring service- with the proposed feature the person will simply have to create a blank repository and enable pre-revprop-change/ pre-uuid-change on and wait for someone to load the content into that repository. After the intial mirroring is done, he can always turn off the pre-uuid-change. It's probably a dangerous feature, and I don't know if it's worth the trouble. I disagree that the UUID should be mirrored. You're loading a *NEW* repository. Thus, it should not have the same UUID as the original. The original continues to exist. Having two repositories with the same UUID is just wrong. That is contrary to the entire design principle.. Agreed. *Universally Unique* Identifier. -Hyrum
Re: Proposal: Change repository's UUID over RA layer
When I've mirrored repositories with the intent of keeping them in sync, I've typically given them the same UUID. I don't know if that has much impact in practice, since I think working copies tend to stick to one of the mirrors (either the RW master or the RO slave). The philosophical question here isn't whether the ID is universally unique but what it's identifying. Is it identifying the repository content or the the container in which the content is held?
Re: Proposal: Change repository's UUID over RA layer
Greg Hudson wrote on Fri, Aug 06, 2010 at 10:49:27 -0400: The philosophical question here isn't whether the ID is universally unique but what it's identifying. Is it identifying the repository content or the the container in which the content is held? The former, if I remember correctly a discussion I participated in (on this list) a few years ago. And even so, we might decide that the admin should setuuid out-of-band of the RA layer. It it isn't unreasonable, given that it's an operation needed exactly once over the lifetime of any repository^Wcontainer instance. Daniel (possibly the discussion was even before I became a committer)
Re: Proposal: Change repository's UUID over RA layer
On Fri, Aug 6, 2010 at 7:34 AM, Branko Čibej br...@xbc.nu wrote: Ahem. You guys have forgotten about Justin's RW-master/RO-slave replication hack, which *requires* the slave repositories to have the same UUID as the master. And that 'svnadmin load' has both --ignore-uuid and --force-uuid. When doing any master/slave initial configuration, doing a local 'svnadmin setuuid' should be sufficient. IOW, I don't see that use case as driving this need. -- justin
Re: Proposal: Change repository's UUID over RA layer
On 06.08.2010 19:26, Justin Erenkrantz wrote: On Fri, Aug 6, 2010 at 7:34 AM, Branko Čibej br...@xbc.nu wrote: Ahem. You guys have forgotten about Justin's RW-master/RO-slave replication hack, which *requires* the slave repositories to have the same UUID as the master. And that 'svnadmin load' has both --ignore-uuid and --force-uuid. When doing any master/slave initial configuration, doing a local 'svnadmin setuuid' should be sufficient. IOW, I don't see that use case as driving this need. -- justin Exatly. And while that's being done locally, one might just as well do the whole 'svnadmin load' which can implicitly set the UUID. Which means we don't need an 'svnadmin setuuid' since loading a dump is pretty much the only time one might reasonably want to change the repository UUID, IMHO. -- Brane
Re: Proposal: Change repository's UUID over RA layer
Hi Daniel, Daniel Shahaf writes: Ramkumar Ramachandra wrote on Sun, Aug 01, 2010 at 11:47:51 +0530: However, Daniel asked me not to expect this and start working on a branch instead after notifying the list- No, I didn't ask you to notify the list; I asked you to start a design discussion on the list. That's a different beast. You should not just tell us Hey, I started a branch for feature X; you should also discuss the plans --- the UI (both for users and admins) and the implementation --- and solicit feedback. Sounds good in theory, but I don't know enough about the infrastructure to sketch out any concrete design plans- the moment I start studying it in this detail, I'll have a mock implementation ready- when I'm there, I think I'll post the RFC patch to the list and wait for feedback. Thanks. -- Ram
Re: Proposal: Change repository's UUID over RA layer
Ramkumar Ramachandra wrote on Fri, Aug 06, 2010 at 07:54:36 +0530: Hi Daniel, Daniel Shahaf writes: Ramkumar Ramachandra wrote on Sun, Aug 01, 2010 at 11:47:51 +0530: However, Daniel asked me not to expect this and start working on a branch instead after notifying the list- No, I didn't ask you to notify the list; I asked you to start a design discussion on the list. That's a different beast. You should not just tell us Hey, I started a branch for feature X; you should also discuss the plans --- the UI (both for users and admins) and the implementation --- and solicit feedback. Sounds good in theory, but I don't know enough about the infrastructure to sketch out any concrete design plans- the moment I start studying it in this detail, I'll have a mock implementation ready- when I'm there, I think I'll post the RFC patch to the list and wait for feedback. The implementation should be trivial (over ra_local and ra_svn; probably over ra_dav too but I don't know that one as well). But what about authz concerns? Do you want to allow any authenticated user to change the repository UUID? Do you want UUID changing to be disallowed by default (unless the server admin took an explicit action)? Thanks. -- Ram
Re: Proposal: Change repository's UUID over RA layer
Ramkumar Ramachandra wrote on Sun, Aug 01, 2010 at 11:47:51 +0530: However, Daniel asked me not to expect this and start working on a branch instead after notifying the list- No, I didn't ask you to notify the list; I asked you to start a design discussion on the list. That's a different beast. You should not just tell us Hey, I started a branch for feature X; you should also discuss the plans --- the UI (both for users and admins) and the implementation --- and solicit feedback.
