feat(desktop): ask consent on attach and take over a foreign runtime with the bundled CLI

desktop/src-tauri/src/claim.rs

@@ -0,0 +1,289 @@
+//! Recording this installation as the runtime owner, through the bundled CLI.
+//!
+//! The claim is only valid against the exact answer the consent prompt was approved from,
+//! so this is a subprocess with expectations on argv rather than an in-process write: the
+//! ownership mutation lease, the subject revalidation and the managing-CLI re-observation
+//! all live in the CLI's `recordServiceOwner`, and re-running them here would be a second
+//! implementation of a rule that has to be identical.
+//!
+//! Like `runtime_stop`, the result is a document, not a guess: `ocx service claim --json`
+//! puts one summary on stdout and this consumes `ok` and the exit code rather than
+//! inferring them. A claim that did not end in exit 0 with `ok:true` is a claim that did
+//! not happen — and a takeover that reached here already stopped the foreign runtime, so
+//! the caller's failure is a stopped runtime with no owner recorded, which the next launch
+//! resolves as an ordinary absence.
+
+use serde::Deserialize;
+use tauri::AppHandle;
+use tauri_plugin_shell::ShellExt;
+use tokio::time::{timeout_at, Instant};
+
+/// The wire version this shell understands.
+pub const SCHEMA: &str = "ocx-service-claim/1";
+
+#[derive(Clone, Debug, PartialEq, Eq, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct ClaimOwnership {
+    pub owner: String,
+    pub install_id: String,
+    pub consent_generation: u64,
+}
+
+#[derive(Clone, Debug, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct ClaimSummary {
+    pub schema: String,
+    pub ok: bool,
+    /// Present on success.
+    pub ownership: Option<ClaimOwnership>,
+    /// Present on failure: the CLI's machine-readable error code.
+    pub code: Option<String>,
+    /// Present on failure.
+    pub message: Option<String>,
+}
+
+/// What the shell concluded.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum ClaimResult {
+    /// The CLI recorded the claim and named the generation it landed at.
+    Recorded(ClaimOwnership),
+    /// It reported anything else, or the run could not be read at all.
+    Failed(String),
+}
+
+impl ClaimResult {
+    #[cfg(test)]
+    pub fn is_recorded(&self) -> bool {
+        matches!(self, Self::Recorded(_))
+    }
+}
+
+/// The arguments a takeover builds from the resolve answer it was approved against.
+///
+/// `Recorded::Unknown` gets no argv: fabricating `--expect-none --expect-revision 0` would claim
+/// against a subject nobody approved, so the answer is None and the caller refuses.
+pub fn args(
+    install_id: &str,
+    recorded: &crate::ownership::Recorded,
+    token: &str,
+) -> Option<Vec<String>> {
+    let mut argv = vec![
+        "service".to_owned(),
+        "claim".to_owned(),
+        "--owner".to_owned(),
+        "desktop".to_owned(),
+        "--install-id".to_owned(),
+        install_id.to_owned(),
+    ];
+    match recorded {
+        crate::ownership::Recorded::None { revision } => {
+            argv.push("--expect-none".to_owned());
+            argv.push("--expect-revision".to_owned());
+            argv.push(revision.to_string());
+        }
+        crate::ownership::Recorded::Owned {
+            ownership,
+            revision,
+        } => {
+            argv.extend([
+                "--expect-owner".to_owned(),
+                match ownership.owner {
+                    crate::ownership::Owner::Cli => "cli".to_owned(),
+                    crate::ownership::Owner::Desktop => "desktop".to_owned(),
+                },
+                "--expect-install-id".to_owned(),
+                ownership.install_id.clone(),
+                "--expect-generation".to_owned(),
+                ownership.consent_generation.to_string(),
+                "--expect-revision".to_owned(),
+                revision.to_string(),
+            ]);
+        }
+        // A takeover is only offered when the record was read; unknown never reaches here,
+        // and refusing beats inventing an approval.
+        crate::ownership::Recorded::Unknown { .. } => return None,
+    }
+    argv.extend([
+        "--expect-compatibility-token".to_owned(),
+        token.to_owned(),
+        "--json".to_owned(),
+    ]);
+    Some(argv)
+}
+
+/// Read one claim summary.
+///
+/// Exit 0 with `ok:true` is the only success — the claim path uses exit 1 with a
+/// machine-readable `code` for subject mismatches and changed compatibility, and both of
+/// those are refusals to re-ask from, not partial writes.
+pub fn read(exit_code: Option<i32>, stdout: &[u8], stderr: &[u8]) -> ClaimResult {
+    let text = String::from_utf8_lossy(stdout);
+    let summary: ClaimSummary = match serde_json::from_str(text.trim()) {
+        Ok(summary) => summary,
+        Err(error) => {
+            let detail = String::from_utf8_lossy(stderr);
+            let detail = detail.trim();
+            let code = exit_code
+                .map(|code| code.to_string())
+                .unwrap_or_else(|| "no exit code".to_owned());
+            return ClaimResult::Failed(if detail.is_empty() {
+                format!("the bundled CLI's claim output could not be read (exit {code}: {error})")
+            } else {
+                format!("the bundled CLI's claim output could not be read (exit {code}): {detail}")
+            });
+        }
+    };
+    if summary.schema != SCHEMA {
+        return ClaimResult::Failed(format!(
+            "the bundled CLI answered with schema {} and this app understands {SCHEMA}",
+            summary.schema
+        ));
+    }
+    if exit_code != Some(0) || !summary.ok {
+        return ClaimResult::Failed(summary.message.unwrap_or_else(|| {
+            format!(
+                "the claim was refused ({})",
+                summary.code.unwrap_or_else(|| "no code".to_owned())
+            )
+        }));
+    }
+    match summary.ownership {
+        Some(ownership) => ClaimResult::Recorded(ownership),
+        None => ClaimResult::Failed(
+            "the claim reported success but carried no ownership record".to_owned(),
+        ),
+    }
+}
+
+/// Run the bundled `ocx service claim`, under the caller's deadline.
+pub async fn run(app: &AppHandle, argv: Vec<String>, deadline: Instant) -> ClaimResult {
+    let command = match app.shell().sidecar("ocx") {
+        Ok(command) => command.args(argv),
+        Err(error) => {
+            return ClaimResult::Failed(format!("the bundled CLI could not be started ({error})"))
+        }
+    };
+    match timeout_at(deadline, command.output()).await {
+        Ok(Ok(output)) => read(output.status.code(), &output.stdout, &output.stderr),
+        Ok(Err(error)) => {
+            ClaimResult::Failed(format!("the bundled CLI could not be run ({error})"))
+        }
+        Err(_) => ClaimResult::Failed(
+            "the bundled CLI did not finish the claim before the deadline".to_owned(),
+        ),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{args, read, ClaimResult};
+    use crate::ownership::{Owner, Recorded};
+
+    fn document(ok: bool, extra: &str) -> String {
+        format!(r#"{{"schema":"ocx-service-claim/1","ok":{ok}{extra}}}"#)
+    }
+
+    #[test]
+    fn the_arguments_carry_the_exact_approved_subject() {
+        let none = args("install-a", &Recorded::None { revision: 0 }, "tok");
+        assert_eq!(
+            none.expect("argv for a read record"),
+            vec![
+                "service",
+                "claim",
+                "--owner",
+                "desktop",
+                "--install-id",
+                "install-a",
+                "--expect-none",
+                "--expect-revision",
+                "0",
+                "--expect-compatibility-token",
+                "tok",
+                "--json",
+            ]
+        );
+        let owned = Recorded::Owned {
+            ownership: crate::ownership::Claim {
+                owner: Owner::Cli,
+                install_id: "npm-1".to_owned(),
+                consent_generation: 2,
+            },
+            revision: 9,
+        };
+        let argv = args("install-a", &owned, "tok").expect("a claim against a read record");
+        assert!(argv
+            .windows(2)
+            .any(|pair| pair == ["--expect-owner", "cli"]));
+        assert!(argv
+            .windows(2)
+            .any(|pair| pair == ["--expect-install-id", "npm-1"]));
+        assert!(argv
+            .windows(2)
+            .any(|pair| pair == ["--expect-generation", "2"]));
+        assert!(argv
+            .windows(2)
+            .any(|pair| pair == ["--expect-revision", "9"]));
+    }
+
+    #[test]
+    fn an_unread_record_gets_no_claim_rather_than_a_fabricated_one() {
+        // Nobody approved a subject the resolve could not read, so there is nothing to claim
+        // against -- and "expect none, revision 0" would be that approval invented.
+        assert!(args(
+            "install-a",
+            &Recorded::Unknown {
+                reason: "why".to_owned()
+            },
+            "tok"
+        )
+        .is_none());
+    }
+
+    #[test]
+    fn a_recorded_claim_is_the_only_success() {
+        let ok = document(
+            true,
+            r#","ownership":{"owner":"desktop","installId":"install-a","consentGeneration":1},"revision":3"#,
+        );
+        let result = read(Some(0), ok.as_bytes(), b"");
+        match result {
+            ClaimResult::Recorded(ownership) => {
+                assert_eq!(ownership.install_id, "install-a");
+                assert_eq!(ownership.consent_generation, 1);
+            }
+            ClaimResult::Failed(reason) => panic!("{reason}"),
+        }
+        // Success has to arrive with exit 0 and the record it wrote.
+        assert!(!read(Some(1), ok.as_bytes(), b"").is_recorded());
+        assert!(!read(Some(0), document(true, "").as_bytes(), b"").is_recorded());
+    }
+
+    #[test]
+    fn a_refusal_carries_the_clis_own_message() {
+        let refused = document(
+            false,
+            r#","code":"service-ownership-subject-mismatch","message":"ownership changed""#,
+        );
+        let result = read(Some(1), refused.as_bytes(), b"");
+        match result {
+            ClaimResult::Failed(reason) => assert!(reason.contains("ownership changed")),
+            ClaimResult::Recorded(_) => panic!("a refused claim is not recorded"),
+        }
+    }
+
+    #[test]
+    fn output_that_cannot_be_read_is_a_failure_not_a_claim() {
+        assert!(!read(Some(0), b"", b"boom").is_recorded());
+        assert!(!read(Some(0), b"not json", b"").is_recorded());
+        assert!(!read(None, b"", b"").is_recorded());
+        let future = document(true, r#","ownership":{"owner":"desktop","installId":"i","consentGeneration":1},"revision":1"#)
+            .replace("ocx-service-claim/1", "ocx-service-claim/2");
+        let result = read(Some(0), future.as_bytes(), b"");
+        assert!(!result.is_recorded());
+        match result {
+            ClaimResult::Failed(reason) => assert!(reason.contains("ocx-service-claim/2")),
+            _ => unreachable!(),
+        }
+    }
+}

desktop/src-tauri/src/lib.rs

@@ -1,4 +1,5 @@
 mod auth;
+mod claim;
 mod endpoint;
 mod exit;
 mod first_run;
@@ -156,6 +157,17 @@ fn retry_startup(app: tauri::AppHandle) {
     startup::begin(&app);
 }
 
+/// The user's answer to the takeover prompt the startup sequence is waiting on.
+///
+/// The sequence holds a oneshot for exactly the duration of the prompt; a decision arriving
+/// with nothing pending is a click after the fact, and it changes nothing.
+#[tauri::command]
+fn decide_takeover(app: tauri::AppHandle, approved: bool) {
+    if let Some(startup) = app.try_state::<startup::Startup>() {
+        startup.decide_takeover(approved);
+    }
+}
+
 pub fn run() {
     let builder = tauri::Builder::default()
         .plugin(tauri_plugin_single_instance::init(|app, _args, _cwd| {
@@ -188,7 +200,8 @@ pub fn run() {
             hide_dashboard,
             startup_snapshot,
             startup_phases,
-            retry_startup
+            retry_startup,
+            decide_takeover
         ])
         .setup(|app| {
             app.manage(AppState::new());