Simple Web Agent Walk-through

A simple web enabled agent that will hook up with a VOLTTRON message bus and allow interaction between it via HTTP. This example agent shows a simple file serving agent, a JSON-RPC based call, and a websocket based connection mechanism.

Starting VOLTTRON Platform


Starting the VOLTTRON platform requires an Activated Environment. Run the following command from the root directory:

. env/bin/activate

In order to start the simple web agent, we need to bind the VOLTTRON instance to the a web server. We need to specify the address and the port for the web server. For example, if we want to bind the localhost:8080 as the web server we start the VOLTTRON platform as follows:

./start-volttron --bind-web-address

Once the platform is started, we are ready to run the Simple Web Agent.

Running Simple Web Agent


The following assumes the shell is located at the VOLTTRON_ROOT.

Copy the following into your shell (save it to a file for executing it again later):

python scripts/ \
    --agent-source examples/SimpleWebAgent \
    --tag simpleWebAgent \
    --vip-identity webagent \
    --force \

This will create a web server on http://localhost:8080. The index.html file under simpleweb/webroot/simpleweb/ can be any HTML page which binds to the VOLTTRON message bus .This provides a simple example of providing a web endpoint in VOLTTRON.

Path based registration examples

  • Files will need to be in webroot/simpleweb in order for them to be browsed from http://localhost:8080/simpleweb/index.html

  • Filename is required as we don’t currently auto-redirect to any default pages as shown in"/simpleweb", os.path.join(WEBROOT))

The following two examples show the way to call either a JSON-RPC (default) endpoint and one that returns a different content-type. With the JSON-RPC example from volttron central we only allow post requests, however this is not required.

  • Endpoint will be available at http://localhost:8080/simple/text"/simple/text", self.text)

  • Endpoint will be available at http://localhost:8080/simple/jsonrpc"/simpleweb/jsonrpc", self.rpcendpoint)

  • text/html content type specified so the browser can act appropriately like [("Content-Type", "text/html")]

  • The default response is application/json so our endpoint returns appropriately with a JSON based response.