schematics/src/symbols/systemd/user_session.rs

use crate::command_runner::CommandRunner;
use crate::symbols::Symbol;
use std::error::Error;
use std::path::Path;

#[derive(Debug)]
pub struct UserSession<'a, U, C> {
  user_name: U,
  command_runner: &'a C,
}

impl<'a, U, C> UserSession<'a, U, C> {
  pub fn new(user_name: U, command_runner: &'a C) -> Self {
    Self {
      user_name,
      command_runner,
    }
  }
}

impl<U: AsRef<str>, C: CommandRunner> Symbol for UserSession<'_, U, C> {
  fn target_reached(&self) -> Result<bool, Box<dyn Error>> {
    let path = Path::new("/var/lib/systemd/linger").join(self.user_name.as_ref());
    Ok(path.exists())
    // Could also do `loginctl show-user ${self.user_name} | grep -F 'Linger=yes`
  }

  fn execute(&self) -> Result<(), Box<dyn Error>> {
    self
      .command_runner
      .run_successfully("loginctl", args!["enable-linger", self.user_name.as_ref()])
  }
}