[Dancer-users] Strange errors while running multiple dancer apps with mount

[Gurunandan Bhat]

On Sun, Jun 3, 2012 at 8:55 PM, Naveed Massjouni <naveedm9 at gmail.com> wrote:

> On Thu, May 31, 2012 at 5:17 PM, Gurunandan Bhat <gbhat at pobox.com> wrote:
> > I have 2 applications that work fine when run individually. One uses
> > sessions (Storable) and the other does not use sessions at all.
> >
> > When mounted as recommended in  Dancer::Deployment however, I get strange
> > errors depending on the sequence that I visit the two applications. app1
> > does not use sessions and app2 uses sessions (Storable)
> >
> > My app.psgi can be viewed here: http://pastie.org/4004017
> >
> > Here is what I find:
> >
> > When I visit http://localhost:5000/app1 first and then
> > http://localhost:5000/app2. app2 dies with an error: "core - Must
> specify
> > session engine in settings prior to using 'session' keyword at...". The
> > Settings section in the Debug panel shows no session related settings
> even
> > though they are present in config.yml
> > When I visit http://localhost:5000/app2 and then
> http://localhost:5000/app1,
> > app2 dies again but with a different error: "core - template - file
> error -
> > signin_header.tt: not found at...". signin_header.tt is used in the
> index
> > template using [% INCLUDE....%] directive of TT. This time, the session
> > related settings are correctly displayed in the debug panel
> > When I visit app2, then app1, then back to app2, I get the session error
> > described in item 1.
> > Sometimes, and this is random, app2 (the one that uses sessions) also
> loses
> > the value of the database configuration parameters (I use
> > Dancer::Plugin::Database) giving me a "...database not defined..." error.
> > But this is once in about 8-10 visits. Situations 1, 2 and 3 however play
> > out each time.
> >
> >
> > It appears to me that if two apps one using sessions and the other not,
> then
> > visiting the application that does not use sessions somehow deletes the
> > session settings of the other application.
> >
> > I can easily fix the error in item 2 (template not found..) by giving the
> > full path of the template, but I would lose the very advantage that makes
> > hosting multiple apps *without making any change* to their configuration
> so
> > attractive.
> >
> > I have tried to debug this for a few days and am unable to figure this.
> > Would really appreciate some help/pointers here.
> >
> >
> > Thank you.
>
> Mounting multiple Dancer apps has been broken for a very long time. It
> has to do with global things interfering with each other. You can
> search the mailing list for alternative solutions. Such as deploying
> each app with it's own starman and proxing to them via nginx. My
> understanding is that it might be fixed when Dancer2 is released. We
> really need to remove the example of mounting multiple apps from the
> documentation.
> -Naveed
>


Ah! Thank you.

Whom do I petition to get this removed from the documentation? I think
there is a reference to this in one of the Advent articles too (not sure,
will check).

Thank you once again for stating this clearly and unambiguously
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