3. Context-driven data flows¶
In FogFlow each worker is an agent to perform the following two type of deployment actions assigned by Topology Master.
- start/terminate a task instance
- add/remove an input stream to an existing running task instance
For example, each worker takes the following steps to start a task instance.
- the worker asks its local docker engine to create a new container for running the new task instance with a specified listening port number
- the task instance starts to run and listening on the given port number to receive input data streams
- the worker sends a configuration object to the running task instance via its listening port
- the worker issues NGSI10 subscriptions on behalf of the running task instance
- the required input data streams flow into the running task instance for further processing via its listening port
- the running task instance processes the received input stream data and then generate its result
- the running task instance publishes the generated result as its output by sending NGSI10 updates