[dancer-users] Multiple apps with Plack and Apache
janet davis
oscarjwoofer at gmail.com
Wed Jul 13 19:25:55 BST 2016
Yes, it would be fantastic if this method worked and I have tried but I get
the following error when switching between app1 and app2. Yes Perl 5.14
sadly, we are due to update to Debian 8 shortly which will bring us up to
5.20.2.
Error while loading /var/www/webapp/app2/bin/app.psgi: Can't locate app2.pm
in @INC (@INC contains: /var/www/webapp/app1/bin/../lib /etc/perl
/usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5
/usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14
/usr/local/lib/site_perl . /etc/apache2) at
/var/www/webapp/app2/bin/app.psgi line 8.\nBEGIN failed--compilation
aborted at /var/www/webapp/app2/bin/app.psgi line 8.
App2 will work after a refresh, but them going back to App1 I get:
and
Error while loading /var/www/webapp/app1/bin/app.psgi: Can't locate app1.pm
in @INC (@INC contains: /var/www/webapp/app2/bin/../lib /etc/perl
/usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5
/usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14
/usr/local/lib/site_perl . /etc/apache2) at
/var/www/webapp/app1/bin/app.psgi line 8.\nBEGIN failed--compilation
aborted at /var/www/webapp/app1/bin/app.psgi line 8
Here's my Apache config:
<Location /app1>
SetHandler perl-script
PerlResponseHandler
Plack::Handler::Apache2
PerlSetVar psgi_app
/var/www/webapp/app1/bin/app.psgi
</Location>
<Location
/app2>
SetHandler
perl-script
PerlResponseHandler
Plack::Handler::Apache2
PerlSetVar psgi_app
/var/www/webapp/app2/bin/app.psgi
</Location>
On Wed, Jul 13, 2016 at 5:14 PM, Chad Wallace <cwallace at lodgingcompany.com>
wrote:
> On Wed, 13 Jul 2016 14:28:23 +0100
> janet davis <oscarjwoofer at gmail.com> wrote:
>
> > Thanks for both of your input, it has really helped a lot.
>
> You're welcome! But I have another suggestion...
>
> After re-reading your original post, I looked up the
> Plack::Handler::Apache2 option, and it looks like it might be better.
> It's at least worth exploring.
>
> From the example in the deployment guide you mentioned, it looks like
> all you'd have to do to your existing virtual host is add a <Location>
> section for each of your apps, like this:
>
> <VirtualHost>
> ServerName www.myserver
>
> [...]
>
> <Location /app1>
> SetHandler perl-script
> PerlResponseHandler Plack::Handler::Apache2
> PerlSetVar psgi_app /websites/app1/app.psgi
> </Location>
> <Location /app2>
> SetHandler perl-script
> PerlResponseHandler Plack::Handler::Apache2
> PerlSetVar psgi_app /websites/app2/app.psgi
> </Location>
> <Location /app3>
> SetHandler perl-script
> PerlResponseHandler Plack::Handler::Apache2
> PerlSetVar psgi_app /websites/app3/app.psgi
> </Location>
>
> [...]
>
> </VirtualHost>
>
> That way, your plack apps will start and stop with your apache server.
>
> I don't have any experience with this approach, so hopefully someone
> else can weigh in on the pros and cons. It seems much simpler to me.
>
> One drawback I can think of is that your apache processes would all
> load a copy of perl, Plack, Dancer and all the rest. It may be better
> for memory usage to use the proxy method, especially if you have dozens
> of apache workers, but only need a few Dancer workers. The impact of
> that would depend on the relative weight of your existing website vs.
> the new apps, and also whether you already use mod_perl and a lot of
> the same modules....
>
> You should definitely try both methods and see which is best. And be
> sure to let us know what you find!
>
>
> > On Wed, Jul 13, 2016 at 12:25 AM, Chad Wallace
> > <cwallace at lodgingcompany.com> wrote:
> >
> > > On Tue, 12 Jul 2016 22:07:56 +0100
> > > janet davis <oscarjwoofer at gmail.com> wrote:
> > >
> > > > The only problem is the uri_base doesn't point to the public
> > > > directory in my application root it points to / so no css/js etc.
> > > >
> > > > I have:
> > > > ProxyPass /app1 http://localhost:5000
> > > > ProxyPassReverse /app1 http://localhost:5000
> > > > And I can reach app1 on myserver.com/app1
> > > >
> > > > Is there anywhere in the config that I can specify the correct
> > > > uri_base per app?
> > >
> > > There's the behind_proxy config option (see Dancer2::Config).
> > >
> > > > I will try using Plack Builder with some example apps. Are there
> > > > any performance implications if I run a lot of Dancer apps in
> > > > this way (15+) alongside my cgi scripts? I don't want to go down
> > > > this route and then discover that I have issues with server
> > > > resources.
> > >
> > > I'm guessing you'll get better performance with them combined. They
> > > should at least use less memory that way, because the single process
> > > would load all modules only once, rather than loading one process
> > > per app, each with its own copy of perl, Plack, Dancer, Moo, etc.
> > >
> > > Adding the mounts with Plack::Builder probably doesn't add too much
> > > overhead. From what I've seen, Plack and Dancer are both designed
> > > to perform and scale well.
> > >
> > > You could test both methods and compare the results.
> > >
> > >
> > > > On Tue, Jul 12, 2016 at 9:21 PM, Chad Wallace
> > > > <cwallace at lodgingcompany.com> wrote:
> > > >
> > > > > On Tue, 12 Jul 2016 19:55:31 +0100
> > > > > janet davis <oscarjwoofer at gmail.com> wrote:
> > > > >
> > > > > > Hi there,
> > > > > >
> > > > > > I have a web server running Apache with a single vhost that
> > > > > > serves a lot of Perl cgi scripts from cgi-bin.
> > > > > >
> > > > > > I've been trying out Dancer, which I really like, but I can't
> > > > > > figure out the best way to deploy apps in my Apache
> > > > > > environment. I want to keep my Apache cgi configuration to
> > > > > > serve legacy scripts but I want to start building new
> > > > > > projects based on psgi in something like Dancer.
> > > > > >
> > > > > > I want Apache to use www.myserver/cgi-bin/appname/script.pl
> > > > > > for old code (which currently works) and www.myserver/app1
> > > > > > for newer Dancer based apps. Please don't think I'm being
> > > > > > lazy by asking, I have read the documentation and looked at
> > > > > > the example for deploying multiple apps via fcgi but I am
> > > > > > still confused as I have limited experience with Apache - I
> > > > > > am working on that. What's the best way to set this up,
> > > > > > bearing in mind that I may want to run say 10-15 Dancer apps
> > > > > > from my server alongside my cgi-scripts? Do I have to set up
> > > > > > a vhost for each app? I have Apache::Plack::Handler but I'm
> > > > > > not sure whether I should be using Plack::Builder to mount my
> > > > > > apps (which is mentioned in an older Dancer Cookbook, but not
> > > > > > the current deployment guide. Can someone help me get on the
> > > > > > right track please?
> > > > >
> > > > > I'm not sure it matches what you currently have in mind, but
> > > > > what I would do is set up www.myserver/app1 with mod_proxy to a
> > > > > standalone Plack/Dancer process for the app. You would need
> > > > > something like this in your VirtualHost for each app:
> > > > >
> > > > > ProxyPass /app1 http://localhost:5000/app1
> > > > >
> > > > > You'd also have to manage starting, stopping and reloading each
> > > > > of your apps on its own, with a dedicated port, like 5000 in
> > > > > the line above.
> > > > >
> > > > > If you wanted to combine your apps into one, you can do that
> > > > > with Plack::Builder in a single app.psgi script. Then you get
> > > > > the benefit of only having one script to start and stop, and
> > > > > one port. I currently do that with one of my apps to separate
> > > > > the AJAX-specific stuff, based on code I found in
> > > > > Dancer2::Cookbook[1]:
> > > > >
> > > > > #!/usr/bin/env perl
> > > > >
> > > > > use strict;
> > > > > use warnings;
> > > > >
> > > > > use FindBin;
> > > > > use lib "$FindBin::Bin/../lib";
> > > > >
> > > > > use Plack::Builder;
> > > > > use newtlc;
> > > > > use newtlc::API;
> > > > >
> > > > > builder {
> > > > > mount '/' => newtlc->to_app;
> > > > > mount '/api' => newtlc::API->to_app;
> > > > > };
> > > > >
> > > > >
> > > > > [1]
> > > > >
> > > > >
> > >
> https://metacpan.org/pod/distribution/Dancer2/lib/Dancer2/Cookbook.pod#App-specific-feature
> > >
> > >
> > > --
> > >
> > > C. Chad Wallace, B.Sc.
> > > The Lodging Company
> > > http://www.lodgingcompany.com/
> > > OpenPGP Public Key ID: 0x262208A0
> > >
> > > _______________________________________________
> > > dancer-users mailing list
> > > dancer-users at dancer.pm
> > > http://lists.preshweb.co.uk/mailman/listinfo/dancer-users
> > >
>
>
> --
>
> C. Chad Wallace, B.Sc.
> The Lodging Company
> http://www.lodgingcompany.com/
> OpenPGP Public Key ID: 0x262208A0
>
> _______________________________________________
> dancer-users mailing list
> dancer-users at dancer.pm
> http://lists.preshweb.co.uk/mailman/listinfo/dancer-users
>
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