Automated SCP file transfers can be orchestrated in your Flux workflow using SCPAction. This action supports file uploads or downloads using SCP. SCP is basically a remote copy (rcp) through a SSH tunnel. It is easy to setup key-based SSH login for your systems, here is one article describing the steps for Mac. You could also run arbitrary system commands or scripts using this action.
Here is a screen shot showing SCPAction configuration that downloads logs from a linux host.
Here is a screen shot showing SCPAction configuration that executes a remote disk check command for a linux host.
A sample test case that shows how this action could be integrated within a Flux workflow using Java API.
Maven users could just drop this dependency in your POM to use this plugin in your project.
Make sure you include this maven repository where the plugin snapshots are deployed.