From 845c344231280edc16c3e6a1ab65b97eb623134c Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Tue, 7 Jun 2022 18:20:51 +0200
Subject: [PATCH] Inform user of what DB engine Garage is running on

---
 src/api/admin/cluster.rs | 2 ++
 src/db/lib.rs            | 5 +++++
 src/db/lmdb_adapter.rs   | 4 ++++
 src/db/sled_adapter.rs   | 4 ++++
 src/db/sqlite_adapter.rs | 4 ++++
 src/garage/admin.rs      | 1 +
 6 files changed, 20 insertions(+)

diff --git a/src/api/admin/cluster.rs b/src/api/admin/cluster.rs
index 6d01317d..4b7716a3 100644
--- a/src/api/admin/cluster.rs
+++ b/src/api/admin/cluster.rs
@@ -19,6 +19,7 @@ pub async fn handle_get_cluster_status(garage: &Arc<Garage>) -> Result<Response<
 	let res = GetClusterStatusResponse {
 		node: hex::encode(garage.system.id),
 		garage_version: garage.system.garage_version(),
+		db_engine: garage.db.engine(),
 		known_nodes: garage
 			.system
 			.get_known_nodes()
@@ -98,6 +99,7 @@ fn get_cluster_layout(garage: &Arc<Garage>) -> GetClusterLayoutResponse {
 struct GetClusterStatusResponse {
 	node: String,
 	garage_version: &'static str,
+	db_engine: String,
 	known_nodes: HashMap<String, KnownNodeResp>,
 	layout: GetClusterLayoutResponse,
 }
diff --git a/src/db/lib.rs b/src/db/lib.rs
index 9fae7cc9..e9d3ea18 100644
--- a/src/db/lib.rs
+++ b/src/db/lib.rs
@@ -63,6 +63,10 @@ pub fn unabort<R, E>(res: TxResult<R, E>) -> TxOpResult<std::result::Result<R, E
 // ----
 
 impl Db {
+	pub fn engine(&self) -> String {
+		self.0.engine()
+	}
+
 	pub fn open_tree<S: AsRef<str>>(&self, name: S) -> Result<Tree> {
 		let tree_id = self.0.open_tree(name.as_ref())?;
 		Ok(Tree(self.0.clone(), tree_id))
@@ -298,6 +302,7 @@ impl<'a> Transaction<'a> {
 // ---- Internal interfaces
 
 pub(crate) trait IDb: Send + Sync {
+	fn engine(&self) -> String;
 	fn open_tree(&self, name: &str) -> Result<usize>;
 	fn list_trees(&self) -> Result<Vec<String>>;
 
diff --git a/src/db/lmdb_adapter.rs b/src/db/lmdb_adapter.rs
index 23b8c87e..74622919 100644
--- a/src/db/lmdb_adapter.rs
+++ b/src/db/lmdb_adapter.rs
@@ -57,6 +57,10 @@ impl LmdbDb {
 }
 
 impl IDb for LmdbDb {
+	fn engine(&self) -> String {
+		"LMDB (using Heed crate)".into()
+	}
+
 	fn open_tree(&self, name: &str) -> Result<usize> {
 		let mut trees = self.trees.write().unwrap();
 		if let Some(i) = trees.1.get(name) {
diff --git a/src/db/sled_adapter.rs b/src/db/sled_adapter.rs
index fb9353f0..982f8d82 100644
--- a/src/db/sled_adapter.rs
+++ b/src/db/sled_adapter.rs
@@ -58,6 +58,10 @@ impl SledDb {
 }
 
 impl IDb for SledDb {
+	fn engine(&self) -> String {
+		"Sled".into()
+	}
+
 	fn open_tree(&self, name: &str) -> Result<usize> {
 		let mut trees = self.trees.write().unwrap();
 		if let Some(i) = trees.1.get(name) {
diff --git a/src/db/sqlite_adapter.rs b/src/db/sqlite_adapter.rs
index 251dcafb..84883772 100644
--- a/src/db/sqlite_adapter.rs
+++ b/src/db/sqlite_adapter.rs
@@ -71,6 +71,10 @@ impl SqliteDbInner {
 }
 
 impl IDb for SqliteDb {
+	fn engine(&self) -> String {
+		"Sqlite3 (using rusqlite crate)".into()
+	}
+
 	fn open_tree(&self, name: &str) -> Result<usize> {
 		let name = format!("tree_{}", name.replace(':', "_COLON_"));
 		let mut this = self.0.lock().unwrap();
diff --git a/src/garage/admin.rs b/src/garage/admin.rs
index 3af8b046..c662aa00 100644
--- a/src/garage/admin.rs
+++ b/src/garage/admin.rs
@@ -672,6 +672,7 @@ impl AdminRpcHandler {
 			self.garage.system.garage_version(),
 		)
 		.unwrap();
+		writeln!(&mut ret, "\nDatabase engine: {}", self.garage.db.engine()).unwrap();
 
 		// Gather ring statistics
 		let ring = self.garage.system.ring.borrow().clone();