webREPLdemo

This is slightly modified Chris Granger's Noir-blog application, a demo for his Noir web framework.

Its main purpose is to provide a showcase for ringMon, a middleware for Ring web library. This library (Ring) is de-facto standard for Clojure web applications.

Once injected into web aplication's Ring chain, ringMon drives a single monitoring web page that displays important application statistics (such as CPU load and raw JMX property values) and more importantly, it provides full featured nREPL front end with syntax colored editor, command history and peristent sessions.

The noirMon also demonstrates how to incorporate ringMon into a typical Noir based application that is deployed on Heroku. cloud platform.

Demo

The addition of a sigle file in project folder (Procfile) enables this application to be deployed on Heroku. You can see it see it in action here.

Since this is a blog app anway, it was convenient to add couple of of blog entries that describe ringMon features in more detail.

The blog contents is kept `sdb.db. New enttries are added using the following procedure:

• Start application locally (see bellow for instructions)
• The initial username is admin , password clojars, this user can be removed once you add yourself as a another user.
• Log in and add/modify blog entry.
• Shut down the application and redeploy it with updated sdb.db on Heroku with:

git commit -a -m "Added new blog article."
git push origin # Update GitHub repository
git push heroku master # rebuild and redeploy on Heroku

Local Usage

To run locally:

lein deps
lein run

Point your browser to localhost:8080.

If you want to do equivalent of lein repl but now using ringMon's nREPL web interface then enter:

lein run -m ringmon.server :local-repl true :port 7777

This will start a separate Jetty instance on port 7777 just to serve the nREPL page. Your default browser window will automatically be opened pointing to the page itself. If :port is set to zero at command line then its value will be autoselected. The default port value is 8888.

If you already have the browser window listening at port 7777 from the previous run, then you should ommit :local-repl option, or set it to false.

lein run -m ringmon.server :port 7777

Note: For the time being (hopefully not for long) only one nREPL session is supported per browser/per client computer, so if you have 2 or more windows within the web browser connected to the same Jetty server, nREPL output will be randomly sprinkled accros all of them. The workaround is to use another browser type side by side (tested on Chrome, Firefox and Safari).

Since both browser and application run locally, the page refresh rate will be adjusted accordingly. At this point noirMon is not runnning yet. You can start it by entering this in nREPL input window:

(use 'noirmon.server)
(-main)

Note that now there are 2 Jetty instances running, one at port 8080 is serving the application, while the ather (at port 7777) is just serving the ringMon's nREPL interface page. This scenario is only possible in local environment since Heroku does not allow more than one server socket per web application process.

The ringMon monitoring page within noirMon itself will not be accessible in this case - you will get ringMon already wrapped into separate web server at port 7777 error message if you try to follow the link from the main blog application page.

License

Copyright (C) 2012 Zoran Tomicic

Distributed under the Eclipse Public License, the same as Clojure.