App Server¶

The App Server (pkg/app/appserver/) manages the lifecycle of Skywire applications within a visor. It handles process management, inter-process communication, and network connectivity for apps.

Application Types¶

Native Apps (In-Process)¶

Native apps run as goroutines within the visor process: - skychat — messaging over Skywire routes - vpn-server / vpn-client — VPN over Skywire routes - skysocks / skysocks-client — SOCKS5 proxy over Skywire routes - skynet — skynet forwarding server

External Apps¶

External apps run as separate processes. Communication with the visor uses a pair of UNIX pipes (file descriptors 3 and 4) inherited by the forked process.

App Configuration¶

Apps are configured in the launcher.apps section of the visor config:

{
  "name": "skychat",
  "args": ["--addr", ":8001"],
  "auto_start": true,
  "port": 1
}

Field	Description
`name`	App binary name (looked up in `launcher.bin_path`)
`args`	Command-line arguments passed to the app
`auto_start`	Whether to start the app on visor startup
`port`	Skywire routing port the app listens on

App Network Interface¶

Apps communicate over the Skywire network via the appnet package. When an app opens a connection to a remote visor, the visor's router establishes a route and provides the app with a bidirectional stream.

The app server tracks: - Running app processes and their PIDs - App connection states - App logs (ring buffer accessible via visor app log <name>)

Runtime App Management¶

Action	CLI command
List apps	`skywire cli visor app ls`
Start app	`skywire cli visor app start <name>`
Stop app	`skywire cli visor app stop <name>`
Set autostart	`skywire cli visor app arg autostart <name> true\\|false`
Set killswitch	`skywire cli visor app arg killswitch <name> true\\|false`
Set secure mode	`skywire cli visor app arg secure <name> true\\|false`
Set network interface	`skywire cli visor app arg netifc <name> <iface>`
View logs	`skywire cli visor app log <name>`