OpenEssence is part of JHU/APL's Suite for Automated Global Electronic bioSurveillance (SAGES). Sages provides a modular, flexible, open source set of tools to aid in the creation of electronic disease surveillance capabilities. OpenEssence provides a web application for data entry, reporting, and visualization with the Sages suite.

You can read more about Sages at the publicity site.

OpenEssence uses Gradle as its build system. Since Gradle comes with a wrapper script that's checked in to source control, you do not need to install Gradle; just run gradlew build in the root project directory to build all artifacts.

Build artifacts can be found in $SUBPROJECT/build/libs, as per Gradle convention. For example, the WAR file built from core can be found in core/build/libs/openessence.war.

OpenEssence comes equipped with a Vagrantfile and Chef scripts to get a development environment up and running as quickly as possible. Here are the steps:

Vagrant can be found at vagrantup.com. If you're on Windows, make sure the installer puts Vagrant in a path with no spaces (the default on newer versions). For example, older versions of Vagrant were installed in C:\Program Files (x86), as per Windows convention. Unfortunately, Vagrant ships with an embedded Ruby environment that doesn't like spaces in path names.

Vagrant uses VirtualBox to manage the virtual machines used for development. If you really don't want to use VirtualBox, you can use any of the providers supported by Vagrant, e.g. VMWare, but be prepared to modify the Vagrantfile.

OpenEssence currently uses two Vagrant plugins: vagrant-omnbius and vagrant-librarian-chef. Install them by running vagrant plugin install vagrant-omnibus and vagrant plugin install vagrant-librarian-chef in your shell. Vagrant is kind enough to add itself to your PATH variable on Windows, so this should just work.

SSH is needed if you want to log in to the VMs. Note that you can get OpenEssence up and running without logging into the VMs, but at some point you'll probably want to do work on the guest instances. On Windows, you can install SSH via Cygwin's openssh package; or you can install a dedicated application like PuTTY.

OpenEssence needs some certs for the frontend to present to the user, and for each machine to communicate with each other. Luckily, we have a convenient Ruby script (chef/sages_dev_cert.rb, run it in the chef directory) you can run to generate everything you need. In the future, it might be nice to integrate this into Vagrant so there's one less thing you have to run, or maybe delegate this to a Chef Server. Pull requests welcome!

GeoServer and PostgreSQL require admin passwords. For GeoServer, create a file called default.rb and put it in the chef/cookbooks/oe-geoserver/attributes directory. The files should look something like this:

default['oe-geoserver']['password'] = 'PASSWORD'

Likewise for the database, create a file called default.rb and put it in the chef/cookbooks/oe-db/attributes directory. The files should look something like this:

default['oe-db']['password'] = 'PASSWORD'

This isn't strictly necessary, but it can make things a lot easier. See the example hosts file in chef/hosts. This link provides a good tutorial for doing this on Windows.

Run vagrant up. This should bring up three VMs: db, geoserver, and web. db contains the PostgreSQL instance, geoserver contains the GIS services, and web contains the frontend webserver (currently Apache). Note that this does not bring up a Tomcat instance to run the application code. Instead, for development, we recommend running Tomcat on the host machine (it's hard to get IDE hot code deployment working on a remote Tomcat). You should be able to hit the webserver at the web.local address (assuming you added it to your hosts file). GeoServer should be reachable at web.local/geoserver and Tomcat should be reachable at web.host.local. See the Apache config for more information.

There's still some work we need to do to make this a little easier. For now, SSH into db (vagrant ssh db) or use pgAdmin to set up your database.

Again, there's more work we can do to integrate this into Vagrant.

If everything goes well, you should now have a running OpenEssence instance.

OpenEssence leverages Gradle's built in IDE support.

Importing the project into IntelliJ IDEA should just work as long as you have the Gradle plugin installed. However, as with most things, Eclipse can require a little more work.

You can either use the Eclipse Gradle Plugin or generate the Eclipse metadata manually. If you use the Gradle Plugin, the projects should be importable as Gradle projects.

If you want to generate the Eclipse metadata manually, run gradlew eclipse. Each project should then be importable as an "Existing Project." Make sure to import the root project, as well as each subproject you want to work on.

There is one caveat to the Eclipse support. Eclipse doesn't support projects made up of subprojects, like IntelliJ does with their "modules." Consequently, multi-project builds in Maven and Gradle require subprojects to be imported as top-level Eclipse projects. But Eclipse also has a restriction against duplicate project names. This means that you would not be able to work on multiple forks of OpenEssence at the same time in Eclipse, since all the forks would have a core project, open-detectors project, etc.

Luckily, Gradle's Eclipse plugin allows us to work around these restrictions by assigning unique names to each project. This is done in each fork's site.gradle file. For example, in our demo build of OpenEssence, we prefix each Eclipse project name with demo- like so:

ext {
    eclipseProjectPrefix = 'demo-'
}

This will result in a project called demo-core, demo-graph, etc, that can be imported alongside the mainline projects.

For more information, see the documentation on Gradle's Eclipse and IDEA plugins.

Feel free to ask technical questions on the sages-health-support mailing list.

For general disease surveillance questions, check out the sages-health-epi mailing list.