From b886c75450e3ee6a7c2b0a8265d7ada20a4d9d75 Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Tue, 6 Sep 2022 17:09:43 +0200
Subject: Make all DB engines optional build features

---
 src/db/Cargo.toml     |  8 +++++---
 src/db/lib.rs         |  4 ++++
 src/garage/Cargo.toml | 12 ++++++++++--
 src/model/Cargo.toml  |  3 +++
 src/model/garage.rs   | 30 ++++++++++++++++++++++++++++--
 5 files changed, 50 insertions(+), 7 deletions(-)

diff --git a/src/db/Cargo.toml b/src/db/Cargo.toml
index 44f0be56..62dda2ca 100644
--- a/src/db/Cargo.toml
+++ b/src/db/Cargo.toml
@@ -21,9 +21,9 @@ err-derive = "0.3"
 hexdump = "0.1"
 tracing = "0.1.30"
 
-heed = { version = "0.11", default-features = false, features = ["lmdb"] }
-rusqlite = "0.27"
-sled = "0.34"
+heed = { version = "0.11", default-features = false, features = ["lmdb"], optional = true }
+rusqlite = { version = "0.27", optional = true }
+sled = { version = "0.34", optional = true }
 
 # cli deps
 clap = { version = "3.1.18", optional = true, features = ["derive", "env"] }
@@ -35,3 +35,5 @@ mktemp = "0.4"
 [features]
 bundled-libs = [ "rusqlite/bundled" ]
 cli = ["clap", "pretty_env_logger"]
+lmdb = [ "heed" ]
+sqlite = [ "rusqlite" ]
diff --git a/src/db/lib.rs b/src/db/lib.rs
index f185114e..5304c195 100644
--- a/src/db/lib.rs
+++ b/src/db/lib.rs
@@ -1,8 +1,12 @@
 #[macro_use]
+#[cfg(feature = "sqlite")]
 extern crate tracing;
 
+#[cfg(feature = "lmdb")]
 pub mod lmdb_adapter;
+#[cfg(feature = "sled")]
 pub mod sled_adapter;
+#[cfg(feature = "sqlite")]
 pub mod sqlite_adapter;
 
 pub mod counted_tree_hack;
diff --git a/src/garage/Cargo.toml b/src/garage/Cargo.toml
index 78579995..00b16ded 100644
--- a/src/garage/Cargo.toml
+++ b/src/garage/Cargo.toml
@@ -74,9 +74,17 @@ base64 = "0.13"
 
 
 [features]
-default = [ "bundled-libs", "metrics" ]
-kubernetes-discovery = [ "garage_rpc/kubernetes-discovery" ]
+default = [ "bundled-libs", "metrics", "sled" ]
+
 k2v = [ "garage_util/k2v", "garage_api/k2v" ]
+
+# Database engines, Sled is still our default even though we don't like it
+sled = [ "garage_model/sled" ]
+lmdb = [ "garage_model/lmdb" ]
+sqlite = [ "garage_model/sqlite" ]
+
+# Automatic registration and discovery via Kubernetes API
+kubernetes-discovery = [ "garage_rpc/kubernetes-discovery" ]
 # Prometheus exporter (/metrics endpoint).
 metrics = [ "garage_api/metrics", "opentelemetry-prometheus", "prometheus" ]
 # Exporter for the OpenTelemetry Collector.
diff --git a/src/model/Cargo.toml b/src/model/Cargo.toml
index 7b831538..cb0017b2 100644
--- a/src/model/Cargo.toml
+++ b/src/model/Cargo.toml
@@ -46,3 +46,6 @@ netapp = "0.4"
 
 [features]
 k2v = [ "garage_util/k2v" ]
+lmdb = [ "garage_db/lmdb" ]
+sled = [ "garage_db/sled" ]
+sqlite = [ "garage_db/sqlite" ]
diff --git a/src/model/garage.rs b/src/model/garage.rs
index 15769a17..19eecb1e 100644
--- a/src/model/garage.rs
+++ b/src/model/garage.rs
@@ -80,6 +80,8 @@ impl Garage {
 		let mut db_path = config.metadata_dir.clone();
 		std::fs::create_dir_all(&db_path).expect("Unable to create Garage meta data directory");
 		let db = match config.db_engine.as_str() {
+			// ---- Sled DB ----
+			#[cfg(feature = "sled")]
 			"sled" => {
 				db_path.push("db");
 				info!("Opening Sled database at: {}", db_path.display());
@@ -91,6 +93,10 @@ impl Garage {
 					.expect("Unable to open sled DB");
 				db::sled_adapter::SledDb::init(db)
 			}
+			#[cfg(not(feature = "sled"))]
+			"sled" => return Err(Error::Message("sled db not available in this build".into())),
+			// ---- Sqlite DB ----
+			#[cfg(feature = "sqlite")]
 			"sqlite" | "sqlite3" | "rusqlite" => {
 				db_path.push("db.sqlite");
 				info!("Opening Sqlite database at: {}", db_path.display());
@@ -98,6 +104,14 @@ impl Garage {
 					.expect("Unable to open sqlite DB");
 				db::sqlite_adapter::SqliteDb::init(db)
 			}
+			#[cfg(not(feature = "sqlite"))]
+			"sqlite" | "sqlite3" | "rusqlite" => {
+				return Err(Error::Message(
+					"sqlite db not available in this build".into(),
+				))
+			}
+			// ---- LMDB DB ----
+			#[cfg(feature = "lmdb")]
 			"lmdb" | "heed" => {
 				db_path.push("db.lmdb");
 				info!("Opening LMDB database at: {}", db_path.display());
@@ -111,10 +125,22 @@ impl Garage {
 					.expect("Unable to open LMDB DB");
 				db::lmdb_adapter::LmdbDb::init(db)
 			}
+			#[cfg(not(feature = "lmdb"))]
+			"lmdb" | "heed" => return Err(Error::Message("lmdb db not available in this build".into())),
+			// ---- Unavailable DB engine ----
 			e => {
 				return Err(Error::Message(format!(
-					"Unsupported DB engine: {} (options: sled, sqlite, lmdb)",
-					e
+					"Unsupported DB engine: {} (options: {})",
+					e,
+					vec![
+						#[cfg(feature = "sled")]
+						"sled",
+						#[cfg(feature = "sqlite")]
+						"sqlite",
+						#[cfg(feature = "lmdb")]
+						"lmdb",
+					]
+					.join(", ")
 				)));
 			}
 		};
-- 
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