Mercurial push locks

[durwin at mgtsciences.com]

Simon King <simon at simonking.org.uk> wrote on 09/27/2014 03:14:15 PM:

> From: Simon King <simon at simonking.org.uk>
> To: durwin at mgtsciences.com
> Cc: Matt Mackall <mpm at selenic.com>, Mercurial mailing list 
> <mercurial at selenic.com>
> Date: 09/27/2014 03:14 PM
> Subject: Re: Mercurial push locks
> 
> On 27 Sep 2014, at 00:16, durwin at mgtsciences.com wrote:
> 
> > Matt Mackall <mpm at selenic.com> wrote on 09/26/2014 03:30:00 PM:
> > 
> > > From: Matt Mackall <mpm at selenic.com> 
> > > To: durwin at mgtsciences.com, 
> > > Cc: Mercurial mailing list <mercurial at selenic.com>, Simon King 
> > > <simon at simonking.org.uk> 
> > > Date: 09/26/2014 03:30 PM 
> > > Subject: Re: Mercurial push locks 
> > > 
> > > On Fri, 2014-09-26 at 11:19 -0600, durwin at mgtsciences.com wrote:
> > > > > > > With the introduction of phases (Mercurial 2.1, Feb 2012), 
pushes 
> > > > may
> > > > > > > now acquire a lock on the sending side (so that it can 
update the 
> > > > phase
> > > > > > > of local commits). Thus, you may get a deadlock if you 
> push inside a
> > > > > > > hook where a lock is already held.
> > > > > > 
> > > > > > This appears to what is occurring.  Is there a way around 
this?  I 
> > > > need to 
> > > > > > perform a push
> > > > > > to the other repository after each push to either.  ShouldI 
change 
> > > > this 
> > > > > > to a script and
> > > > > > run it in an 'at' job delayed a minute?
> > > > > 
> > > > > What version of Mercurial are you running on the server?
> > > > 
> > > > Mercurial version 2.6.3
> > > 
> > > Hmmm, shouldn't be a problem here: the changegroup hook is run
> > > immediately after lock release.
> > > 
> > > Perhaps you can create a minimal model of your flow:
> > > 
> > > $ hg init local
> > > $ hg init server1
> > > # add push hook
> > > $ hg init server2
> > > 
> > > ..and see if you can get it to lock.
> > 
> > I do have a 'test' repository where all I have are two files.  The
> hook always works for me.  In fact the project repository all ways 
> works for me.  There was a time where I would see the lock, but that
> is no longer occurring.  I tried logging into server as one of the 
> users having the problem and cloned their repository, but it would 
> not lock up, it pushed just fine. 
> > 
> 
> I’m not sure I understand your setup here. Based on your earlier 
> emails you say you have:
> 
> Local machine
>   -> push to ssh://server//home/svnuser/project-hg/WebApplication
>     -> changegroup hook pushing to 
/home/svnuser/project-hg/WebApplication/
> 
> This doesn’t appear to make any sense (changegroup hook pushing to 
> the current repository), so perhaps you’ve changed the paths and 
> they’re not really like this.
> 
> For the first push, I assume that each user has their own account on
> the server, but file permissions are set up such that they all have 
> write privileges on the first server-side repo. This is a potential 
> source of problems if the users don’t have appropriate umask and 
> group settings, as one user could create files that can’t be updated
> by other users.
> 
> The hook then uses sudo to run the second push as the user 
> “svnuser”, and it calls a program called “hg-svnuser”. This raises a
> couple more questions:

I have 2 servers, each with a clone of the project.  Webuser works off 
ServerA,
while the rest work off ServerB.  When a push is done to ServerB, it must 
then
push to ServerA.  I copied hg executable to hg-svnuser then set the SUID
and the user to 'svnuser' with the intent on getting consistent 
properties.
Every user is in the 'svnuser' sudo group with NOPASSWD defined for 
hg-svnuser executable.

> 
> 1. Do all users have the same sudo privileges? Perhaps the blocking 
> happens because sudo is trying to prompt for a password in some cases?
> 
> 2. Is “hg-svnuser” a different installation of mercurial than the 
> one invoked as part of the “initial” push? If so, have you checked 
> the version numbers of both installations?
> 
> I don’t know what you mean when you say you logged into the server 
> as a different user and cloned their repository - perhaps you could 
> explain those steps in detail.

I had logged into one users login on ServerB to see if I can duplicate 
problem.

$ ssh user1 at serverb
$ hg clone ssh://serverb//home/svnuser/project/ project/

Then make an edit, commit, then push.

None of the users are actually working *on* the server.  They are using 
Windows,
most using Netbeans, one using Cygwin.

I even had one create a new clone, but still had lockups.

I did remove the hook for testing and there was no lockups.
I am trying to recode hook to perform a push to other server *after* user 
has
competed (using at).

> 
> Thanks,
> 
> Simon


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