refactor(userLifecycle): add user lifecycle, more clarety + better integration for the future

src/application/services/user_lifecycle_service.rs

@@ -0,0 +1,184 @@
+//! User-lifecycle dispatcher + the always-on `AuditLifecycleHook`.
+//!
+//! [`UserLifecycleService`] aggregates every registered
+//! [`UserLifecycleHook`] and fans out each lifecycle event with
+//! per-event failure semantics. See `user_lifecycle.rs` for the trait
+//! contract and tips for implementors.
+//!
+//! [`AuditLifecycleHook`] lives in this file (not under
+//! `infrastructure/services/`) because it's cross-cutting — no domain
+//! service owns "user-lifecycle audit", and the hook is small enough that
+//! a separate module would be ceremony. Every other hook lives with the
+//! service that owns its work (see `architecture/user-lifecycle.md`).
+
+use std::sync::Arc;
+
+use async_trait::async_trait;
+
+use crate::application::ports::user_lifecycle::{DeletionMode, LogoutReason, UserLifecycleHook};
+use crate::common::errors::DomainError;
+use crate::domain::entities::user::User;
+
+/// Composite dispatcher for user-lifecycle events.
+///
+/// Mirrors the [`FileLifecycleService`] shape: a `Vec<Arc<dyn ...>>` and a
+/// builder. The per-event failure semantics differ from the file-side
+/// (file events are sync fire-and-forget; user events have per-method
+/// rules — see the trait docstring).
+pub struct UserLifecycleService {
+    hooks: Vec<Arc<dyn UserLifecycleHook>>,
+}
+
+impl Default for UserLifecycleService {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl UserLifecycleService {
+    pub fn new() -> Self {
+        Self { hooks: Vec::new() }
+    }
+
+    pub fn with_hook(mut self, hook: Arc<dyn UserLifecycleHook>) -> Self {
+        self.hooks.push(hook);
+        self
+    }
+
+    /// Created: log-and-continue. If a hook returns `Err`, the user is
+    /// still created — the next login's `on_user_login` will retry
+    /// idempotently. See tip #6 in the trait docstring.
+    pub async fn dispatch_created(&self, user: &User) {
+        for h in &self.hooks {
+            if let Err(e) = h.on_user_created(user).await {
+                tracing::error!(
+                    target: "user_lifecycle",
+                    hook = h.name(),
+                    user_id = %user.id(),
+                    error = %e,
+                    "on_user_created failed; will retry on next login"
+                );
+            }
+        }
+    }
+
+    /// Login: log-and-continue. Same reasoning as `dispatch_created`.
+    /// Must fire BEFORE `user.register_login()` so that hooks observing
+    /// `last_login_at().is_none()` correctly detect the first-ever login.
+    pub async fn dispatch_login(&self, user: &User) {
+        for h in &self.hooks {
+            if let Err(e) = h.on_user_login(user).await {
+                tracing::error!(
+                    target: "user_lifecycle",
+                    hook = h.name(),
+                    user_id = %user.id(),
+                    error = %e,
+                    "on_user_login failed; will retry on next login"
+                );
+            }
+        }
+    }
+
+    /// Logout: fire-and-forget. Spawned so the HTTP response doesn't wait
+    /// for downstream cache flushes. Takes ownership of `User` because the
+    /// spawn outlives the caller's borrow.
+    pub fn dispatch_logout(&self, user: User, reason: LogoutReason) {
+        let hooks = self.hooks.clone();
+        tokio::spawn(async move {
+            for h in &hooks {
+                if let Err(e) = h.on_user_logout(&user, reason).await {
+                    tracing::error!(
+                        target: "user_lifecycle",
+                        hook = h.name(),
+                        reason = ?reason,
+                        user_id = %user.id(),
+                        error = %e,
+                        "on_user_logout failed"
+                    );
+                }
+            }
+        });
+    }
+
+    /// Deleted: log-and-continue (post-commit today). PR 4 refactors
+    /// `delete_user_admin` to expose a transaction handle and switches
+    /// this to abort-on-first-Err to make cleanup atomic with the user
+    /// DELETE. See tip #7 in the trait docstring.
+    pub async fn dispatch_deleted(&self, user: &User, mode: DeletionMode) {
+        for h in &self.hooks {
+            if let Err(e) = h.on_user_deleted(user, mode).await {
+                tracing::error!(
+                    target: "user_lifecycle",
+                    hook = h.name(),
+                    mode = ?mode,
+                    user_id = %user.id(),
+                    error = %e,
+                    "on_user_deleted failed"
+                );
+            }
+        }
+    }
+}
+
+// ─────────────────────────────────────────────────────────────────────────────
+// AuditLifecycleHook
+//
+// Always-on observer. Emits one structured `tracing::info!(target: "audit",
+// ...)` line per event. The only hook registered in PR 1; subsequent PRs
+// add HomeFolderLifecycleHook, AuthzCacheLifecycleHook, etc., each living
+// next to the service it works for.
+// ─────────────────────────────────────────────────────────────────────────────
+
+/// Cross-cutting audit observer for user-lifecycle events. Co-located with
+/// the dispatcher because audit has no domain owner.
+pub struct AuditLifecycleHook;
+
+#[async_trait]
+impl UserLifecycleHook for AuditLifecycleHook {
+    fn name(&self) -> &'static str {
+        "audit"
+    }
+
+    async fn on_user_created(&self, user: &User) -> Result<(), DomainError> {
+        tracing::info!(
+            target: "audit",
+            event = "user.created",
+            user_id = %user.id(),
+            username = %user.username(),
+        );
+        Ok(())
+    }
+
+    async fn on_user_login(&self, user: &User) -> Result<(), DomainError> {
+        tracing::info!(
+            target: "audit",
+            event = "user.login",
+            user_id = %user.id(),
+            username = %user.username(),
+            first_login = user.last_login_at().is_none(),
+        );
+        Ok(())
+    }
+
+    async fn on_user_logout(&self, user: &User, reason: LogoutReason) -> Result<(), DomainError> {
+        tracing::info!(
+            target: "audit",
+            event = "user.logout",
+            user_id = %user.id(),
+            username = %user.username(),
+            reason = ?reason,
+        );
+        Ok(())
+    }
+
+    async fn on_user_deleted(&self, user: &User, mode: DeletionMode) -> Result<(), DomainError> {
+        tracing::info!(
+            target: "audit",
+            event = "user.deleted",
+            user_id = %user.id(),
+            username = %user.username(),
+            mode = ?mode,
+        );
+        Ok(())
+    }
+}