Set better default 'diesel::SQLite' options.

The options set WAL, a 1s busy timeout, and enables foreign keys.

This also adds a focused 'databases::Config::figment()', used to
retrieve a focused figment for a given config.

contrib/lib/src/databases/config.rs

@@ -78,12 +78,29 @@ impl Config {
     /// # }
     /// ```
     pub fn from(db_name: &str, rocket: &rocket::Rocket) -> Result<Config, figment::Error> {
+        Config::figment(db_name, rocket).extract::<Self>()
+    }
+
+    /// Returns a `Figment` focused on the configuration for the database with
+    /// name `db_name`.
+    ///
+    /// # Example
+    ///
+    /// ```rust
+    /// use rocket::Rocket;
+    /// use rocket_contrib::databases::Config;
+    ///
+    /// fn pool(rocket: &Rocket) {
+    ///     let my_db_figment = Config::figment("my_db", rocket);
+    ///     let mysql_prod_figment = Config::figment("mysql_prod", rocket);
+    /// }
+    /// ```
+    pub fn figment(db_name: &str, rocket: &rocket::Rocket) -> Figment {
         let db_key = format!("databases.{}", db_name);
         let key = |name: &str| format!("{}.{}", db_key, name);
         Figment::from(rocket.figment())
-            .merge(Serialized::default(&key("pool_size"), rocket.config().workers * 2))
-            .merge(Serialized::default(&key("timeout"), 5))
-            .extract_inner::<Self>(&db_key)
+            .join(Serialized::default(&key("pool_size"), rocket.config().workers * 2))
+            .join(Serialized::default(&key("timeout"), 5))
+            .focus(&db_key)
     }
 }
-

contrib/lib/src/databases/poolable.rs

@@ -110,9 +110,32 @@ impl Poolable for diesel::SqliteConnection {
     type Error = std::convert::Infallible;
 
     fn pool(db_name: &str, rocket: &rocket::Rocket) -> PoolResult<Self> {
+        use diesel::{SqliteConnection, connection::SimpleConnection};
+        use diesel::r2d2::{CustomizeConnection, ConnectionManager, Error, Pool};
+
+        #[derive(Debug)]
+        struct Customizer;
+
+        impl CustomizeConnection<SqliteConnection, Error> for Customizer {
+            fn on_acquire(&self, conn: &mut SqliteConnection) -> Result<(), Error> {
+                conn.batch_execute("\
+                    PRAGMA journal_mode = WAL;\
+                    PRAGMA busy_timeout = 1000;\
+                    PRAGMA foreign_keys = ON;\
+                ").map_err(Error::QueryError)?;
+
+                Ok(())
+            }
+        }
+
         let config = Config::from(db_name, rocket)?;
-        let manager = diesel::r2d2::ConnectionManager::new(&config.url);
-        Ok(r2d2::Pool::builder().max_size(config.pool_size).build(manager)?)
+        let manager = ConnectionManager::new(&config.url);
+        let pool = Pool::builder()
+            .connection_customizer(Box::new(Customizer))
+            .max_size(config.pool_size)
+            .build(manager)?;
+
+        Ok(pool)
     }
 }
 
@@ -160,8 +183,50 @@ impl Poolable for rusqlite::Connection {
     type Error = std::convert::Infallible;
 
     fn pool(db_name: &str, rocket: &rocket::Rocket) -> PoolResult<Self> {
-        let config = Config::from(db_name, rocket)?;
-        let manager = r2d2_sqlite::SqliteConnectionManager::file(&*config.url);
+        use rocket::figment::providers::Serialized;
+
+        #[derive(Debug, serde::Deserialize, serde::Serialize)]
+        #[serde(rename_all = "snake_case")]
+        enum OpenFlag {
+            ReadOnly,
+            ReadWrite,
+            Create,
+            Uri,
+            Memory,
+            NoMutex,
+            FullMutex,
+            SharedCache,
+            PrivateCache,
+            Nofollow,
+        }
+
+        let figment = Config::figment(db_name, rocket);
+        let config: Config = figment.extract()?;
+        let open_flags: Vec<OpenFlag> = figment
+            .join(Serialized::default("open_flags", <Vec<OpenFlag>>::new()))
+            .extract_inner("open_flags")?;
+
+        let mut flags = rusqlite::OpenFlags::default();
+        for flag in open_flags {
+            let sql_flag = match flag {
+                OpenFlag::ReadOnly => rusqlite::OpenFlags::SQLITE_OPEN_READ_ONLY,
+                OpenFlag::ReadWrite => rusqlite::OpenFlags::SQLITE_OPEN_READ_WRITE,
+                OpenFlag::Create => rusqlite::OpenFlags::SQLITE_OPEN_CREATE,
+                OpenFlag::Uri => rusqlite::OpenFlags::SQLITE_OPEN_URI,
+                OpenFlag::Memory => rusqlite::OpenFlags::SQLITE_OPEN_MEMORY,
+                OpenFlag::NoMutex => rusqlite::OpenFlags::SQLITE_OPEN_NO_MUTEX,
+                OpenFlag::FullMutex => rusqlite::OpenFlags::SQLITE_OPEN_FULL_MUTEX,
+                OpenFlag::SharedCache => rusqlite::OpenFlags::SQLITE_OPEN_SHARED_CACHE,
+                OpenFlag::PrivateCache => rusqlite::OpenFlags::SQLITE_OPEN_PRIVATE_CACHE,
+                OpenFlag::Nofollow => rusqlite::OpenFlags::SQLITE_OPEN_NOFOLLOW,
+            };
+
+            flags.insert(sql_flag)
+        };
+
+        let manager = r2d2_sqlite::SqliteConnectionManager::file(&*config.url)
+            .with_flags(flags);
+
         Ok(r2d2::Pool::builder().max_size(config.pool_size).build(manager)?)
     }
 }

contrib/lib/tests/databases.rs

@@ -29,7 +29,7 @@ mod rusqlite_integration_test {
         use rocket::figment::{Figment, util::map};
 
         let options = map!["url" => ":memory:"];
-        let config = Figment::from(rocket::Config::default())
+        let config = Figment::from(rocket::Config::debug_default())
             .merge(("databases", map!["test_db" => &options]))
             .merge(("databases", map!["test_db_2" => &options]));
 
@@ -100,7 +100,7 @@ mod drop_runtime_test {
     async fn test_drop_runtime() {
         use rocket::figment::{Figment, util::map};
 
-        let config = Figment::from(rocket::Config::default())
+        let config = Figment::from(rocket::Config::debug_default())
             .merge(("databases", map!["test_db" => map!["url" => ""]]));
 
         let rocket = rocket::custom(config).attach(TestDb::fairing());

core/lib/Cargo.toml

@@ -37,7 +37,7 @@ atomic = "0.5"
 parking_lot = "0.11"
 ubyte = {version = "0.10", features = ["serde"] }
 serde = { version = "1.0", features = ["derive"] }
-figment = { version = "0.10.2", features = ["toml", "env"] }
+figment = { version = "0.10.4", features = ["toml", "env"] }
 rand = "0.8"
 either = "1"
 pin-project-lite = "0.2"