Question

I’ve installed Snap/Haskell on my production Ubuntu server (on EC2), and checked-out my project – but how do I run it?

I mean, locally, I run it from command line:

project-name -p 8000

Does snap come with it’s own web-server (it looks like it), and if so how do I go about configuring it to run as a daemon of some sort?

Any tips?

Edit 2:

On the wiki they say:

snap-server is an HTTP server library that supports the interface
defined in snap-core.

While here, the haskell wiki about “Deployment/Backend options for your haskell web code” says that Snap:

includes its own server. see Web/Frameworks

But HOW? How would I run it’s own server? Why must I know about deployment of the damn thing if I am just interested in programming…

Edit: related question: Deploy Haskell code that uses the Snap Framework

Answer 1

Ok, so after some digging and asking, here is what I came up with.

Big idea

Compile your Snap application into a binary and then run it as a service with the help of upstart.

Step by Step

1. Compile your webapp. For the sake of this example, we’ll assume the webapp is at /home/john/webapps/mysite:

   $ cd /home/john/webapps/mysite
   $ cabal install
   ...
   Preprocessing executable 'mysite` for 'mysite-0.1'...
   Installing executable(s) in /home/john/.cabal/bin
   

   As we can see the, the binary is placed in /home/john/.cabal/bin. You may move it to any place you like, but we’ll leave it there.

2. Create a log in your application folder, otherwise snap will complain:

   $ mkdir /home/john/webapps/mysite/log
   

3. Now we will create a service that will run our webapp. To do so we will use Ubuntu’s service facility called upstart.

   a) We name our service simply by creating a conf file with the desired name in the /etc/init/ directory. Let’s call it mysite:

   $ sudo vi /etc/init/mysite.conf
   

   b) Now let’s add the description of what our service is:

   start on startup
   chdir /home/john/webapps/mysite
   exec /home/john/.cabal/bin/mysite -p 80
   

   First, we say that the service should run on startup (or on bootup) of the system.

   Second, since snap needs it’s snaplets and other static resources (like the log directory we created earlier) – we tell the service to run inside our project’s directory.

   Lastly, we specify the binary that actually will run as a service: /home/john/.cabal/bin/mysite. We pass the -p 80 parameter to the snap webserver to make it run on port 80. (Note: you have to disable all apache and nginx servers, so that they don’t take up that port any more)

4. Done. You can check if it is running and start it manually if you need to:

   initctl list | grep mysite
   initctl start mysite