swarmctl: interactive setup walks the first-run ceremony

swarmctl setup with no subcommand checks the setup status first, then takes the open steps one at a time: prompts for input, shows a running action as one live line, prints the store keys, root token and new password under a warning until the operator confirms, and names the deploy option for a step this host cannot do. It calls the code of bao init, bao grant-bootstrap, user add, forge make-admin, agent create, agent permissions set and agent set-state. Refuses without root or a terminal.

swarmctl/src/setup.rs

@@ -356,23 +356,30 @@ pub(crate) fn render(steps: &[Step]) -> String {
 ///
 /// `target` and `users_file` arrive as the results of resolving them, so a
 /// host that lacks either still reports the steps that need neither.
-pub(crate) fn status(target: Result<Target>, users_file: Result<std::path::PathBuf>) -> bool {
+pub(crate) fn status(target: &Result<Target>, users_file: &Result<std::path::PathBuf>) -> bool {
     let observed = observe(target, users_file);
     let steps = classify(&observed);
     print!("{}", render(&steps));
     complete(&steps)
 }
 
-fn observe(target: Result<Target>, users_file: Result<std::path::PathBuf>) -> Observed {
+/// Run every check once. The inputs are borrowed so that `swarmctl setup` can
+/// look again after each step.
+pub(crate) fn observe(
+    target: &Result<Target>,
+    users_file: &Result<std::path::PathBuf>,
+) -> Observed {
     let store = bao_status();
     let granter = granter();
     let policy_units = policy_units();
     let admin_user = users_file
-        .map_err(|e| unset_reason(&e))
-        .and_then(|path| has_admin_user(&path).map_err(|e| format!("{e:#}")));
+        .as_ref()
+        .map_err(unset_reason)
+        .and_then(|path| has_admin_user(path).map_err(|e| format!("{e:#}")));
     let agents = target
-        .map_err(|e| unset_reason(&e))
-        .and_then(|t| agents(&t).map_err(|e| format!("{e:#}")));
+        .as_ref()
+        .map_err(unset_reason)
+        .and_then(|t| agents(t).map_err(|e| format!("{e:#}")));
     Observed {
         store,
         granter,
@@ -467,6 +474,20 @@ fn granter() -> Result<Granter, String> {
     Ok(Granter { state, uploaded })
 }
 
+/// Whether this host has the granter unit, which only the host running
+/// swarm-bao does.
+pub(crate) fn granter_unit_exists() -> bool {
+    run(Command::new("systemctl").args([
+        "show",
+        GRANTER_UNIT,
+        "-p",
+        "LoadState",
+        "-p",
+        "ActiveState",
+    ]))
+    .is_ok_and(|shown| parse_unit_state(&shown.stdout, GRANTER_UNIT).is_ok())
+}
+
 /// `ActiveState` out of `systemctl show -p LoadState -p ActiveState`.
 fn parse_unit_state(shown: &str, unit: &str) -> Result<String, String> {
     let field = |name: &str| {