The application (written in perl) is used for environmental monitoring.

The two sorts of plugins we have discussed would

• Define new data fields that are calculated based on existing data. For example if you have air temperature and humidity, but want a dew point field, you can write a dew point plugin, install it and then any sensors that can provide the required fields will magically also provide dewpoint.
• Define an action. The app has the ability to trigger a notification if certain events occur. Right now we only offer one common behavior. We would like to allow our customers to create additional behaviors. For example, an action might be "Send SMS Message". Actions would need to have some UI associated with them.

The two types of plugins need not operate in the same way, as long as they are easy to install.

Plugins only need to run on the same machine as is hosting the main application.

The basic flow of execution would be:

1. App collects data from sensor
2. App calculates any custom fields from field plugins
3. App checks for any conditions that would cause an alert
4. If an alert occurs do any actions associated with the alert.

Worst case, we will be dealing with data collection occuring at most tens of times an hour across hundreds of sensors with tens of fields each. Depending on the connection type, it can take as little as 2 seconds to get data from a sensor, or as much as 2 minutes.

Thanks for the ideas.