refactor: extract embedded startup server helpers (#3660)

docs/architecture/migration-progress.md

@@ -5,22 +5,17 @@ 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-ecstore-rebalance-entry-flow`
-- Baseline: completed `E-015/E-REBALANCE-009`.
-- Stacked on: merged ECStore layout foundation, format layout ownership, and
-  endpoint layout move slices plus the set-format heal, pool-space layout
-  helper, rebalance support helper, pool-space builder, rebalance metadata
-  helper, rebalance worker helper, rebalance migration helper, rebalance state
-  impl, rebalance control impl, rebalance runtime loop, rebalance entry flow,
-  rebalance unit-test split, and rebalance type-owner slices.
+- Branch: `overtrue/arch-embedded-builder-startup-context`
+- Baseline: completed `R-034/R-035`.
+- Stacked on: embedded runtime hook and shutdown glue extraction slices.
 - PR type for this branch: `pure-move`
 - Runtime behavior changes: none.
-- Rust code changes: move ECStore rebalance control, runtime, entry flow,
-  inline tests, and type contracts into dedicated rebalance submodules while
-  preserving public root paths.
+- Rust code changes: move embedded startup config preparation and S3-only HTTP
+  server startup into startup server helpers while preserving embedded builder
+  behavior.
 - CI/script changes: none.
-- Docs changes: record the combined ECStore rebalance control/runtime/entry
-  flow, test-module split, and type-owner split slices.
+- Docs changes: record the embedded startup config and HTTP startup owner
+  slices.
 
 ## Phase 0 Tasks
 
@@ -2245,6 +2240,32 @@ 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-036` Extract embedded startup config preparation boundary.
+  - Do: move embedded temporary volume allocation, custom volume directory
+    creation, and embedded `Config` construction behind startup server helpers.
+  - Acceptance: embedded builder still creates a temporary volume when none is
+    provided, creates missing custom volume directories, disables console for
+    embedded S3 startup, and keeps the temp-dir guard alive until success.
+  - Must preserve: temp-dir cleanup-on-failure behavior, configured address,
+    access key, secret key, region, volume ordering, directory creation error
+    text, and no new normal startup behavior.
+  - Verification: focused startup server 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-037` Extract embedded S3-only HTTP startup boundary.
+  - Do: move embedded S3-only HTTP server startup behind a startup server
+    helper that returns the bound address and shutdown handle.
+  - Acceptance: embedded startup keeps console disabled for the HTTP server,
+    keeps using the same readiness object, and preserves the shutdown handle
+    and bound address used by `RustFSServer`.
+  - Must preserve: S3-only embedded HTTP config, readiness sharing, startup
+    error propagation, shutdown signaling, bound endpoint reporting, and no
+    public embedded API behavior changes.
+  - Verification: focused startup server 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
@@ -2488,20 +2509,33 @@ Status values: `[ ]` not started, `[~]` in progress, `[x]` complete, `[!]` block
 ## Next PRs
 
 1. `pure-move`: continue pruning residual embedded startup-only orchestration
-   after the runtime hook and shutdown glue boundaries land.
+   after the builder config and S3-only HTTP startup boundaries land.
 
 ## Pre-Push Review Log
 
 | Expert | Status | Notes |
 |---|---|---|
-| Quality/architecture | passed | R-034 and R-035 move embedded runtime hooks and async shutdown glue into startup owners while keeping the embedded builder focused on startup orchestration. |
-| Migration preservation | passed | Observability error prefixes, embedded crypto log fields, trusted-proxy timing, cancellation, audit cleanup, HTTP shutdown, temp-dir cleanup, and stopped logs stay in the same order. |
-| Testing/verification | passed | Focused runtime/embedded checks, RustFS lib check, architecture/layer guards, formatting, diff hygiene, Rust risk scan, and pre-commit gate passed. |
+| Quality/architecture | passed | R-036 and R-037 move embedded builder config preparation and S3-only HTTP startup into startup server helpers without exposing new public API. |
+| Migration preservation | passed | Temp-dir guard lifetime, volume directory creation, embedded config fields, console-disabled S3 startup, readiness sharing, shutdown handle, and bound address behavior stay unchanged. |
+| Testing/verification | passed | Focused startup server/embedded checks, RustFS lib check, architecture/layer guards, formatting, diff hygiene, Rust risk scan, and pre-commit gate passed. |
 
 ## Verification Notes
 
 Passed before push:
 
+- Issue #660 R-036/R-037 current slice:
+  - `cargo test -p rustfs --lib startup_server -- --nocapture`: passed.
+  - `cargo test -p rustfs --lib embedded -- --nocapture`: passed.
+  - `cargo check -p rustfs --lib`: passed.
+  - `./scripts/check_architecture_migration_rules.sh`: passed.
+  - `./scripts/check_layer_dependencies.sh`: passed.
+  - `cargo fmt --all --check`: passed.
+  - `git diff --check`: passed.
+  - Rust risk scan on changed Rust files: passed; only test-only
+    `expect` calls and the existing embedded temp-dir cleanup path were
+    present.
+  - `make pre-commit`: passed.
+
 - Issue #660 R-034/R-035 current slice:
   - `cargo test -p rustfs --lib startup_runtime_hooks -- --nocapture`:
     passed.

rustfs/src/embedded.rs

@@ -46,16 +46,17 @@
 //! storage engine uses process-global singletons (`OnceLock`). Attempting to
 //! start a second server will return an error.
 
-use crate::config::Config;
-use crate::server::{ShutdownHandle, start_http_server};
+use crate::server::ShutdownHandle;
 use crate::startup_lifecycle::{log_embedded_server_ready, publish_embedded_startup_ready};
 use crate::startup_runtime_hooks::init_embedded_runtime_hooks;
-use crate::startup_server::init_embedded_startup_listen_context;
+use crate::startup_server::{
+    EmbeddedStartupConfig, init_embedded_startup_listen_context, prepare_embedded_startup_config, start_embedded_http_server,
+};
 use crate::startup_services::init_embedded_startup_runtime_services;
 use crate::startup_shutdown::run_embedded_server_shutdown;
 use crate::startup_storage::{init_embedded_startup_storage_foundation, init_embedded_startup_storage_runtime};
 use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr};
-use std::path::{Path, PathBuf};
+use std::path::PathBuf;
 use std::sync::atomic::{AtomicBool, Ordering};
 use tokio_util::sync::CancellationToken;
 
@@ -237,31 +238,15 @@ impl RustFSServerBuilder {
             Ok(())
         };
 
-        // Keep a TempDir guard alive so that if build fails the directory is
-        // cleaned up automatically. We disarm (keep) on success.
-        let mut temp_dir_guard: Option<tempfile::TempDir> = None;
-        if self.volumes.is_empty() {
-            let dir = tempfile::tempdir().map_err(|e| ServerError::Init(format!("failed to create temp dir: {e}")))?;
-            self.volumes.push(dir.path().display().to_string());
-            temp_dir_guard = Some(dir);
-        }
-
-        // Ensure volume directories exist.
-        for v in &self.volumes {
-            let p = Path::new(v);
-            if !p.exists() {
-                tokio::fs::create_dir_all(p)
-                    .await
-                    .map_err(|e| ServerError::Init(format!("failed to create volume dir {v}: {e}")))?;
-            }
-        }
-
-        // Build Config.
-        let mut config = Config::new(&self.address, self.volumes.clone());
-        config.access_key = self.access_key.clone();
-        config.secret_key = self.secret_key.clone();
-        config.region = Some(self.region.clone());
-        config.console_enable = false;
+        let EmbeddedStartupConfig { config, temp_dir_guard } = prepare_embedded_startup_config(
+            self.address.clone(),
+            self.access_key.clone(),
+            self.secret_key.clone(),
+            self.volumes.clone(),
+            self.region.clone(),
+        )
+        .await
+        .map_err(|e| ServerError::Init(e.to_string()))?;
 
         // --- Initialization sequence (mirrors main.rs::run) ---
 
@@ -279,10 +264,9 @@ impl RustFSServerBuilder {
             .await
             .map_err(|e| ServerError::Init(e.to_string()))?;
 
-        // Start HTTP server.
-        let mut s3_config = config.clone();
-        s3_config.console_enable = false;
-        let (shutdown_handle, bound_addr) = start_http_server(&s3_config, listen_context.readiness.clone()).await?;
+        let http_server = start_embedded_http_server(&config, listen_context.readiness.clone()).await?;
+        let shutdown_handle = http_server.shutdown_handle;
+        let bound_addr = http_server.bound_addr;
         let ctx = CancellationToken::new();
         let shutdown_embedded_server = || {
             shutdown_handle.signal();

rustfs/src/startup_server.rs

@@ -24,8 +24,10 @@ use rustfs_utils::net::parse_and_resolve_address;
 use std::{
     io::{Error, Result},
     net::SocketAddr,
+    path::Path,
     sync::Arc,
 };
+use tempfile::TempDir;
 use tracing::{debug, error, info, warn};
 
 const LOG_COMPONENT_MAIN: &str = "main";
@@ -50,6 +52,16 @@ pub struct EmbeddedStartupListenContext {
     pub server_address: String,
 }
 
+pub(crate) struct EmbeddedStartupConfig {
+    pub config: Config,
+    pub(crate) temp_dir_guard: Option<TempDir>,
+}
+
+pub(crate) struct EmbeddedHttpServer {
+    pub shutdown_handle: ShutdownHandle,
+    pub bound_addr: SocketAddr,
+}
+
 pub struct StartupHttpServers {
     pub state_manager: Arc<ServiceStateManager>,
     pub s3_shutdown_tx: Option<ShutdownHandle>,
@@ -105,6 +117,38 @@ pub async fn init_startup_listen_context(config: &Config) -> Result<StartupListe
     })
 }
 
+pub(crate) async fn prepare_embedded_startup_config(
+    address: String,
+    access_key: String,
+    secret_key: String,
+    mut volumes: Vec<String>,
+    region: String,
+) -> Result<EmbeddedStartupConfig> {
+    let mut temp_dir_guard = None;
+    if volumes.is_empty() {
+        let dir = tempfile::tempdir().map_err(|err| Error::other(format!("failed to create temp dir: {err}")))?;
+        volumes.push(dir.path().display().to_string());
+        temp_dir_guard = Some(dir);
+    }
+
+    for volume in &volumes {
+        let path = Path::new(volume);
+        if !path.exists() {
+            tokio::fs::create_dir_all(path)
+                .await
+                .map_err(|err| Error::other(format!("failed to create volume dir {volume}: {err}")))?;
+        }
+    }
+
+    let mut config = Config::new(&address, volumes);
+    config.access_key = access_key;
+    config.secret_key = secret_key;
+    config.region = Some(region);
+    config.console_enable = false;
+
+    Ok(EmbeddedStartupConfig { config, temp_dir_guard })
+}
+
 pub async fn init_embedded_startup_listen_context(config: &Config) -> Result<EmbeddedStartupListenContext> {
     let readiness = Arc::new(GlobalReadiness::new());
 
@@ -138,6 +182,16 @@ pub async fn init_embedded_startup_listen_context(config: &Config) -> Result<Emb
     })
 }
 
+pub(crate) async fn start_embedded_http_server(config: &Config, readiness: Arc<GlobalReadiness>) -> Result<EmbeddedHttpServer> {
+    let s3_config = s3_http_server_config(config);
+    let (shutdown_handle, bound_addr) = start_http_server(&s3_config, readiness).await?;
+
+    Ok(EmbeddedHttpServer {
+        shutdown_handle,
+        bound_addr,
+    })
+}
+
 pub async fn init_startup_http_servers(config: &Config, readiness: Arc<GlobalReadiness>) -> Result<StartupHttpServers> {
     init_capacity_management().await;
     let state_manager = Arc::new(ServiceStateManager::new());
@@ -224,7 +278,9 @@ fn console_http_server_config(config: &Config) -> Option<Config> {
 
 #[cfg(test)]
 mod tests {
-    use super::{DEFAULT_CREDENTIALS_WARNING_MESSAGE, console_http_server_config, s3_http_server_config};
+    use super::{
+        DEFAULT_CREDENTIALS_WARNING_MESSAGE, console_http_server_config, prepare_embedded_startup_config, s3_http_server_config,
+    };
     use crate::config::Config;
 
     #[test]
@@ -292,4 +348,46 @@ mod tests {
         assert!(!DEFAULT_CREDENTIALS_WARNING_MESSAGE.contains(rustfs_credentials::DEFAULT_ACCESS_KEY));
         assert!(!DEFAULT_CREDENTIALS_WARNING_MESSAGE.contains(rustfs_credentials::DEFAULT_SECRET_KEY));
     }
+
+    #[tokio::test]
+    async fn prepare_embedded_startup_config_creates_temp_volume_when_missing() {
+        let prepared = prepare_embedded_startup_config(
+            "127.0.0.1:9000".to_string(),
+            "access".to_string(),
+            "secret".to_string(),
+            Vec::new(),
+            "us-west-2".to_string(),
+        )
+        .await
+        .expect("embedded startup config should be prepared");
+
+        assert_eq!(prepared.config.address, "127.0.0.1:9000");
+        assert_eq!(prepared.config.access_key, "access");
+        assert_eq!(prepared.config.secret_key, "secret");
+        assert_eq!(prepared.config.region.as_deref(), Some("us-west-2"));
+        assert!(!prepared.config.console_enable);
+        assert_eq!(prepared.config.volumes.len(), 1);
+        assert!(std::path::Path::new(&prepared.config.volumes[0]).exists());
+        assert!(prepared.temp_dir_guard.is_some());
+    }
+
+    #[tokio::test]
+    async fn prepare_embedded_startup_config_creates_missing_custom_volume() {
+        let parent = tempfile::tempdir().expect("temp parent");
+        let volume = parent.path().join("data");
+
+        let prepared = prepare_embedded_startup_config(
+            "127.0.0.1:9000".to_string(),
+            "access".to_string(),
+            "secret".to_string(),
+            vec![volume.display().to_string()],
+            "us-east-1".to_string(),
+        )
+        .await
+        .expect("embedded startup config should create custom volume");
+
+        assert_eq!(prepared.config.volumes, vec![volume.display().to_string()]);
+        assert!(volume.exists());
+        assert!(prepared.temp_dir_guard.is_none());
+    }
 }