[dancer-users] Multiple apps with Plack and Apache

[Chad Wallace]

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/
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