Creating Resources
WattDepot: A system for collecting and storing data from
electricity meters for smart grid research and experimentation.
As discussed in the RestApi, there is a hierarchy of resources in WattDepot: Users own Sources, and Sources contain SensorData. This page explains how to create Users, Sources, and SensorData.
Unfortunately, there is currently no user-friendly tool for creating the resources. They must either be created by hand-edited XML, or programmatically through the RestApi.
If you are creating a small number of relatively homogeneous resources, it is straightforward to
write the XML for them. In the WattDepot distribution, there is a directory
src/main/resources/xml/example-resources that contains example XML for a User and several
Sources. You can use these as templates and create your own User(s) and Source(s). The RestApi also
has example XML for each resource, and the PropertyDictionary describes the canonical properties
used for resources.
Once you have created the XML for your resources, you need to load it into the server. The server
will look for default resources in a directory named default-resources in the server subdirectory.
Each type of resource should be in a separate subdirectory, users for Users, sources for
Sources, and sensordata for SensorData. So for example, Sources should be placed in
~/.wattdepot/server/default-resources/sources (assuming the default server subdirectory name is
used). The WattDepot server looks for this directory when it starts up, so either start the server,
or if it is already running, shut it down and restart it.
Note that the server will examine the default-resources directory each time it starts and try to
load any resources it finds. Since the resources placed here are generally intended to be loaded
once, the next time the server is restarted it will attempt to recreate the resources and generate
error messages. For this reason, you should move the default-resources directory aside after you
have successfully loaded the resources once, for example by renaming the directory to
default-resources-stored.
Sources can be created through the RestApi, so depending on your application, you might want to create the resources you need programmatically. This might be appropriate if you always create Sources with a particular name. If you end up writing a general purpose tool for creating resources, we'd be happy to add it to WattDepot.