refactor: return embedded identity from startup (#3666)

docs/architecture/migration-progress.md

@@ -5,17 +5,15 @@ Status values: `[ ]` not started, `[~]` in progress, `[x]` complete, `[!]` block
 ## Current Context
 
 - Issue: [`rustfs/backlog#660`](https://github.com/rustfs/backlog/issues/660)
-- Branch: `overtrue/arch-embedded-builder-shell`
-- Baseline: completed `R-042/R-043`.
-- Stacked on: embedded handle boundary slice.
+- Branch: `overtrue/arch-embedded-startup-identity-flow`
+- Baseline: completed `R-044/R-045`.
+- Stacked on: embedded builder shell slice.
 - PR type for this branch: `pure-move`
 - Runtime behavior changes: none.
-- Rust code changes: keep the public embedded builder as a thin shell over
-  crate-only startup arguments and move embedded port probing behind
-  startup-server helpers.
-- CI/script changes: make the unsafe allowance checker avoid a local
-  `pipefail` false positive after `rg -q` matches nearby `SAFETY:` comments.
-- Docs changes: record the embedded builder shell slices.
+- Rust code changes: hide embedded startup argument fields behind crate-only
+  setters and return public server identity from the startup result.
+- CI/script changes: none.
+- Docs changes: record the embedded startup identity slices.
 
 ## Phase 0 Tasks
 
@@ -2367,6 +2365,29 @@ Status values: `[ ]` not started, `[~]` in progress, `[x]` complete, `[!]` block
     migration/layer guards, formatting, diff hygiene, Rust risk scan, branch
     freshness check, pre-commit quality gate, and three-expert review.
 
+- [x] `R-046` Encapsulate embedded startup argument mutation.
+  - Do: hide embedded startup argument fields behind crate-only setter methods
+    used by the public builder.
+  - Acceptance: public builder fluent methods still apply the same address,
+    credential, region, and volume values in the same order.
+  - Must preserve: builder method signatures, default values, `volume` append
+    semantics, `volumes` replacement semantics, and startup input ownership.
+  - Verification: focused startup-embedded and embedded checks, RustFS lib
+    check, migration/layer guards, formatting, diff hygiene, Rust risk scan,
+    branch freshness check, pre-commit quality gate, and three-expert review.
+
+- [x] `R-047` Return embedded server identity from startup result.
+  - Do: let the crate-only startup result carry the access key, secret key, and
+    region used by the public server handle.
+  - Acceptance: public server accessors still expose the configured values
+    without the public builder duplicating identity assembly.
+  - Must preserve: startup error mapping, readiness logging order, endpoint
+    address handling, shutdown handle ownership, and no public API signature
+    changes.
+  - Verification: focused startup-embedded and embedded checks, RustFS lib
+    check, migration/layer guards, formatting, diff hygiene, Rust risk scan,
+    branch freshness check, pre-commit quality gate, and three-expert review.
+
 - [x] `E-001/E-SET-001` Add ECStore layout skeleton and set-layout boundary.
   - Do: create the ECStore internal layout ownership buckets and pin static set
     layout versus runtime `Sets`/`SetDisks` orchestration boundaries before any
@@ -2609,21 +2630,35 @@ Status values: `[ ]` not started, `[~]` in progress, `[x]` complete, `[!]` block
 
 ## Next PRs
 
-1. `pure-move`: continue pruning residual embedded builder/startup-only
-   boundaries after the embedded builder shell slice lands.
+1. `pure-move`: continue pruning residual embedded handle/startup-only
+   boundaries after the embedded startup identity slice lands.
 
 ## Pre-Push Review Log
 
 | Expert | Status | Notes |
 |---|---|---|
-| Quality/architecture | passed | R-044 and R-045 keep the public embedded builder as a thin shell over crate-only startup args and move port probing behind startup-server helpers without widening the public API. |
-| Migration preservation | passed | Builder defaults, fluent setters, volume replacement, credential/region accessors, public port helper signature, and localhost ephemeral port behavior stay unchanged. |
-| Testing/verification | passed | Focused embedded/startup-embedded/startup-server checks, RustFS lib check, architecture/layer/unsafe guards, formatting, diff hygiene, Rust risk scan, and pre-commit gate passed. |
+| Quality/architecture | passed | R-046 and R-047 hide startup argument mutation behind crate-only methods and move public server identity assembly into the startup result without widening the public API. |
+| Migration preservation | passed | Builder setter semantics, public server identity accessors, endpoint handling, startup error mapping, and shutdown ownership stay unchanged. |
+| Testing/verification | passed | Focused startup-embedded/embedded checks, RustFS lib check, architecture/layer/unsafe guards, formatting, diff hygiene, Rust risk scan, and pre-commit gate passed. |
 
 ## Verification Notes
 
 Passed before push:
 
+- Issue #660 R-046/R-047 current slice:
+  - `cargo test -p rustfs --lib startup_embedded -- --nocapture`: passed.
+  - `cargo test -p rustfs --lib embedded -- --nocapture`: passed.
+  - `cargo check -p rustfs --lib`: passed.
+  - `cargo fmt --all --check`: passed.
+  - `git diff --check`: passed.
+  - `./scripts/check_architecture_migration_rules.sh`: passed.
+  - `./scripts/check_layer_dependencies.sh`: passed.
+  - `./scripts/check_unsafe_code_allowances.sh`: passed.
+  - Rust risk scan on changed Rust files: passed; matches were limited to
+    existing embedded doc examples.
+  - `make pre-commit`: passed; nextest ran 6324 tests with 6324 passed and
+    111 skipped, and doctests passed.
+
 - Issue #660 R-044/R-045 current slice:
   - `cargo test -p rustfs --lib embedded -- --nocapture`: passed.
   - `cargo test -p rustfs --lib startup_embedded -- --nocapture`: passed.

rustfs/src/embedded.rs

@@ -160,25 +160,25 @@ impl RustFSServerBuilder {
     /// [`build`](Self::build), but that is too late for the earlier
     /// initialization that depends on the configured address.
     pub fn address(mut self, addr: impl Into<String>) -> Self {
-        self.startup_args.address = addr.into();
+        self.startup_args.set_address(addr.into());
         self
     }
 
     /// Set the S3 access key (default: `"rustfsadmin"`).
     pub fn access_key(mut self, key: impl Into<String>) -> Self {
-        self.startup_args.access_key = key.into();
+        self.startup_args.set_access_key(key.into());
         self
     }
 
     /// Set the S3 secret key (default: `"rustfsadmin"`).
     pub fn secret_key(mut self, key: impl Into<String>) -> Self {
-        self.startup_args.secret_key = key.into();
+        self.startup_args.set_secret_key(key.into());
         self
     }
 
     /// Set the AWS region (default: `"us-east-1"`).
     pub fn region(mut self, region: impl Into<String>) -> Self {
-        self.startup_args.region = region.into();
+        self.startup_args.set_region(region.into());
         self
     }
 
@@ -187,13 +187,13 @@ impl RustFSServerBuilder {
     /// If no volumes are added, a temporary directory with a single drive is
     /// created automatically (and cleaned up on [`RustFSServer::shutdown`]).
     pub fn volume(mut self, path: impl Into<String>) -> Self {
-        self.startup_args.volumes.push(path.into());
+        self.startup_args.push_volume(path.into());
         self
     }
 
     /// Set multiple volume paths at once, replacing any previously set volumes.
     pub fn volumes(mut self, paths: Vec<String>) -> Self {
-        self.startup_args.volumes = paths;
+        self.startup_args.set_volumes(paths);
         self
     }
 
@@ -212,17 +212,13 @@ impl RustFSServerBuilder {
     }
 
     async fn do_build(&mut self) -> Result<RustFSServer, ServerError> {
-        let startup_args = self.startup_args.clone();
-        let access_key = startup_args.access_key.clone();
-        let secret_key = startup_args.secret_key.clone();
-        let region = startup_args.region.clone();
-        let started = run_embedded_startup(startup_args).await?;
+        let started = run_embedded_startup(self.startup_args.clone()).await?;
 
         let server = RustFSServer {
             address: started.bound_addr,
-            access_key,
-            secret_key,
-            region,
+            access_key: started.access_key,
+            secret_key: started.secret_key,
+            region: started.region,
             shutdown_handle: Some(started.shutdown_handle),
             cancel_token: started.cancel_token,
             temp_dir: started.temp_dir,

rustfs/src/startup_embedded.rs

@@ -28,11 +28,11 @@ use tokio_util::sync::CancellationToken;
 
 #[derive(Clone)]
 pub(crate) struct EmbeddedStartupArgs {
-    pub address: String,
-    pub access_key: String,
-    pub secret_key: String,
-    pub volumes: Vec<String>,
-    pub region: String,
+    address: String,
+    access_key: String,
+    secret_key: String,
+    volumes: Vec<String>,
+    region: String,
 }
 
 impl EmbeddedStartupArgs {
@@ -45,10 +45,37 @@ impl EmbeddedStartupArgs {
             region: rustfs_config::RUSTFS_REGION.to_string(),
         }
     }
+
+    pub(crate) fn set_address(&mut self, address: String) {
+        self.address = address;
+    }
+
+    pub(crate) fn set_access_key(&mut self, access_key: String) {
+        self.access_key = access_key;
+    }
+
+    pub(crate) fn set_secret_key(&mut self, secret_key: String) {
+        self.secret_key = secret_key;
+    }
+
+    pub(crate) fn set_region(&mut self, region: String) {
+        self.region = region;
+    }
+
+    pub(crate) fn push_volume(&mut self, path: String) {
+        self.volumes.push(path);
+    }
+
+    pub(crate) fn set_volumes(&mut self, paths: Vec<String>) {
+        self.volumes = paths;
+    }
 }
 
 pub(crate) struct EmbeddedStartedServer {
     pub bound_addr: SocketAddr,
+    pub access_key: String,
+    pub secret_key: String,
+    pub region: String,
     pub shutdown_handle: ShutdownHandle,
     pub cancel_token: CancellationToken,
     pub temp_dir: Option<PathBuf>,
@@ -68,13 +95,24 @@ impl From<io::Error> for EmbeddedStartupError {
 }
 
 pub(crate) async fn run_embedded_startup(args: EmbeddedStartupArgs) -> Result<EmbeddedStartedServer, EmbeddedStartupError> {
+    let EmbeddedStartupArgs {
+        address,
+        access_key,
+        secret_key,
+        volumes,
+        region,
+    } = args;
+    let server_access_key = access_key.clone();
+    let server_secret_key = secret_key.clone();
+    let server_region = region.clone();
+
     // Build is allowed to fail before irreversible global initialization
     // (for example on temporary I/O or directory setup errors), and in that
     // case callers can retry.
     let mut startup_guard = EmbeddedStartupGuard::new();
 
     let EmbeddedStartupConfig { config, temp_dir_guard } =
-        prepare_embedded_startup_config(args.address, args.access_key, args.secret_key, args.volumes, args.region)
+        prepare_embedded_startup_config(address, access_key, secret_key, volumes, region)
             .await
             .map_err(init_error)?;
 
@@ -134,6 +172,9 @@ pub(crate) async fn run_embedded_startup(args: EmbeddedStartupArgs) -> Result<Em
 
     Ok(EmbeddedStartedServer {
         bound_addr,
+        access_key: server_access_key,
+        secret_key: server_secret_key,
+        region: server_region,
         shutdown_handle,
         cancel_token,
         temp_dir: temp_dir_guard.map(|guard| guard.keep()),
@@ -158,4 +199,22 @@ mod tests {
         assert_eq!(args.region, rustfs_config::RUSTFS_REGION);
         assert!(args.volumes.is_empty());
     }
+
+    #[test]
+    fn embedded_startup_args_setters_preserve_public_builder_inputs() {
+        let mut args = EmbeddedStartupArgs::new_default();
+
+        args.set_address("127.0.0.1:9100".to_string());
+        args.set_access_key("custom-access".to_string());
+        args.set_secret_key("custom-secret".to_string());
+        args.set_region("test-region".to_string());
+        args.push_volume("/tmp/one".to_string());
+        args.set_volumes(vec!["/tmp/two".to_string(), "/tmp/three".to_string()]);
+
+        assert_eq!(args.address, "127.0.0.1:9100");
+        assert_eq!(args.access_key, "custom-access");
+        assert_eq!(args.secret_key, "custom-secret");
+        assert_eq!(args.region, "test-region");
+        assert_eq!(args.volumes, vec!["/tmp/two", "/tmp/three"]);
+    }
 }