# Socket and servers

Source: https://libtmux.org/en/py/stable/topics/socket-and-servers/

> Select a server socket, check liveness, and detect a replacement daemon.

A tmux server is selected by its Unix-domain socket. Use different sockets for
independent servers, such as a development session and an isolated test server.
Choose the default socket, a named socket (`-L`), or an explicit path (`-S`).

## Naming a server

[`Server()`](<https://libtmux.org/en/py/stable/reference/libtmux-server/>) selects the default socket. Pass `socket_name="work"` to
select a named socket, or `socket_path="/tmp/tmux-1000/work"` for an
explicit path.

```python
default_server = libtmux.Server()
named = libtmux.Server(socket_name="work")
```

Choose either a socket name or a socket path. tmux uses `TMUX_TMPDIR` to
resolve the directory for default and named sockets.

[`Server(socket_name_factory=...)`](<https://libtmux.org/en/py/stable/reference/libtmux-server/>) accepts a callable that generates socket
names. Use a unique name for each isolated test server.

## Is the server actually there?

A server handle does not prove that the target server is running. Use a liveness
check when your program needs to distinguish a live server from an unavailable
socket:

[`Server.is_alive`](<https://libtmux.org/en/py/stable/reference/libtmux-server-is_alive/>) returns a boolean indicating whether the server
responds.

```python
if server.is_alive():
    server.sessions
```

## Killing a server, and telling two apart

Killing a server ends all its sessions. Use this only for a server your program
owns; for narrower cleanup, kill the session or pane you created.

Call [`server.kill_server()`](<https://libtmux.org/en/py/stable/reference/libtmux-server-kill_server/>). [`Server.__eq__`](<https://libtmux.org/en/py/stable/reference/libtmux-server-__eq__/>) compares [`socket_name`](<https://libtmux.org/en/py/stable/reference/libtmux-server-socket_name/>) and
[`socket_path`](https://libtmux.org/en/tmux/latest/catalog/formats/socket_path/) when deciding whether two handles select the same endpoint.

A restarted server can reuse a socket path while having different state. Do
not treat a matching path as proof that a cached object still exists.