Move database logic into submodule and do simple version check

blahctl/src/main.rs

@@ -57,7 +57,10 @@ enum Command {
 }
 
 #[derive(Debug, clap::Subcommand)]
+#[allow(clippy::large_enum_variant)]
 enum DbCommand {
+    /// Create and initialize database.
+    Init,
     /// Set user property, possibly adding new users.
     SetUser {
         #[command(flatten)]
@@ -144,8 +147,6 @@ impl User {
     }
 }
 
-static INIT_SQL: &str = include_str!("../../blahd/init.sql");
-
 fn main() -> Result<()> {
     let cli = <Cli as clap::Parser>::parse();
 
@@ -157,9 +158,15 @@ fn main() -> Result<()> {
             io::stdout().write_all(pubkey_doc.as_bytes())?;
         }
         Command::Database { database, command } => {
-            let conn = Connection::open(database).context("failed to open database")?;
-            conn.execute_batch(INIT_SQL)
-                .context("failed to initialize database")?;
+            use rusqlite::OpenFlags;
+
+            let mut flags = OpenFlags::SQLITE_OPEN_READ_WRITE | OpenFlags::SQLITE_OPEN_NO_MUTEX;
+            flags.set(
+                OpenFlags::SQLITE_OPEN_CREATE,
+                matches!(command, DbCommand::Init),
+            );
+            let conn =
+                Connection::open_with_flags(database, flags).context("failed to open database")?;
             main_db(conn, command)?;
         }
         Command::Api { url, command } => build_rt()?.block_on(main_api(url, command))?,
@@ -177,6 +184,7 @@ fn build_rt() -> Result<Runtime> {
 
 fn main_db(conn: Connection, command: DbCommand) -> Result<()> {
     match command {
+        DbCommand::Init => {}
         DbCommand::SetUser { user, permission } => {
             let userkey = build_rt()?.block_on(user.fetch_key())?;
 

blahd/config.example.toml

@@ -3,11 +3,16 @@
 # the default value.
 
 [database]
+# (Required)
 # The path to the main SQLite database.
 # The file will be created and initialized if not exist, but missing directory
 # will not.
 path = "/var/lib/blahd/db.sqlite"
 
+# Whether to create and initialize the database if `path` does not exist.
+# Note that parent directory will never be created and must already exist.
+create = true
+
 [server]
 
 # (Required)

blahd/schema.sql

@@ -1,5 +1,5 @@
-PRAGMA journal_mode=WAL;
-PRAGMA foreign_keys=TRUE;
+-- TODO: We are still in prototyping phase. Database migration is not
+-- implemented and layout can change at any time.
 
 CREATE TABLE IF NOT EXISTS `user` (
     `uid`           INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,

blahd/src/config.rs

@@ -20,6 +20,8 @@ pub struct Config {
 pub struct DatabaseConfig {
     #[serde_inline_default("/var/lib/blahd/db.sqlite".into())]
     pub path: PathBuf,
+    #[serde_inline_default(true)]
+    pub create: bool,
 }
 
 #[serde_inline_default]

blahd/src/database.rs

@@ -0,0 +1,68 @@
+use std::ops::DerefMut;
+use std::sync::Mutex;
+
+use anyhow::{ensure, Context, Result};
+use rusqlite::{params, Connection, OpenFlags};
+
+use crate::config::DatabaseConfig;
+
+static INIT_SQL: &str = include_str!("../schema.sql");
+
+// Simple and stupid version check for now.
+// `echo -n 'blahd-database-0' | sha256sum | head -c5` || version
+const APPLICATION_ID: i32 = 0xd9e_8400;
+
+#[derive(Debug)]
+pub struct Database {
+    conn: Mutex<Connection>,
+}
+
+impl Database {
+    pub fn open(config: &DatabaseConfig) -> Result<Self> {
+        let mut flags = OpenFlags::SQLITE_OPEN_READ_WRITE | OpenFlags::SQLITE_OPEN_NO_MUTEX;
+        if !config.path.try_exists()? {
+            flags.set(OpenFlags::SQLITE_OPEN_CREATE, config.create);
+        }
+
+        let mut conn = Connection::open_with_flags(&config.path, flags)
+            .context("failed to connect database")?;
+        // Connection-specific pragmas.
+        conn.pragma_update(None, "journal_mode", "WAL")?;
+        conn.pragma_update(None, "foreign_keys", "TRUE")?;
+
+        if conn.query_row(r"SELECT COUNT(*) FROM sqlite_schema", params![], |row| {
+            row.get::<_, u64>(0)
+        })? != 0
+        {
+            let cur_app_id =
+                conn.pragma_query_value(None, "application_id", |row| row.get::<_, i32>(0))?;
+            ensure!(
+                cur_app_id == (APPLICATION_ID),
+                "database is non-empty with a different application_id. \
+                migration is not implemented yet. \
+                got: {cur_app_id:#x}, expect: {APPLICATION_ID:#x} \
+                ",
+            );
+        }
+
+        let txn = conn.transaction()?;
+        txn.execute_batch(INIT_SQL)
+            .context("failed to initialize database")?;
+        txn.pragma_update(None, "application_id", APPLICATION_ID)?;
+        txn.commit()?;
+
+        Ok(Self {
+            conn: Mutex::new(conn),
+        })
+    }
+
+    pub fn get(&self) -> impl DerefMut<Target = Connection> + '_ {
+        self.conn.lock().unwrap()
+    }
+}
+
+#[test]
+fn init_sql_valid() {
+    let conn = Connection::open_in_memory().unwrap();
+    conn.execute_batch(INIT_SQL).unwrap();
+}

blahd/src/event.rs

@@ -115,9 +115,8 @@ pub async fn handle_ws(st: Arc<AppState>, ws: &mut WebSocket) -> Result<Infallib
         let auth = serde_json::from_str::<WithSig<AuthPayload>>(&payload)?;
         st.verify_signed_data(&auth)?;
 
-        st.conn
-            .lock()
-            .unwrap()
+        st.db
+            .get()
             .query_row(
                 r"
                 SELECT `uid`

blahd/src/main.rs

@@ -16,6 +16,7 @@ use blah::types::{
     RoomAttrs, ServerPermission, Signee, UserKey, WithSig,
 };
 use config::Config;
+use database::Database;
 use ed25519_dalek::SIGNATURE_LENGTH;
 use middleware::{ApiError, OptionalAuth, SignedJson};
 use rusqlite::{named_params, params, Connection, OptionalExtension, Row, ToSql};
@@ -27,6 +28,7 @@ use uuid::Uuid;
 #[macro_use]
 mod middleware;
 mod config;
+mod database;
 mod event;
 mod utils;
 
@@ -63,9 +65,7 @@ fn main() -> Result<()> {
     match cli {
         Cli::Serve { config } => {
             let config = parse_config(&config)?;
-            let db = rusqlite::Connection::open(&config.database.path)
-                .context("failed to open database")?;
-            let st = AppState::init(config, db).context("failed to initialize state")?;
+            let st = AppState::init(config).context("failed to initialize state")?;
             tokio::runtime::Builder::new_multi_thread()
                 .enable_all()
                 .build()
@@ -82,7 +82,7 @@ fn main() -> Result<()> {
 // Locks must be grabbed in the field order.
 #[derive(Debug)]
 struct AppState {
-    conn: Mutex<rusqlite::Connection>,
+    db: Database,
     used_nonces: Mutex<ExpiringSet<u32>>,
     event: event::State,
 
@@ -90,13 +90,9 @@ struct AppState {
 }
 
 impl AppState {
-    fn init(config: Config, conn: rusqlite::Connection) -> Result<Self> {
-        static INIT_SQL: &str = include_str!("../init.sql");
-
-        conn.execute_batch(INIT_SQL)
-            .context("failed to initialize database")?;
+    fn init(config: Config) -> Result<Self> {
         Ok(Self {
-            conn: Mutex::new(conn),
+            db: Database::open(&config.database).context("failed to open database")?,
             used_nonces: Mutex::new(ExpiringSet::new(Duration::from_secs(
                 config.server.timestamp_tolerance_secs,
             ))),
@@ -236,9 +232,8 @@ async fn room_list(
     let query = |sql: &str, params: &[(&str, &dyn ToSql)]| -> Result<RoomList, ApiError> {
         let mut last_rid = None;
         let rooms = st
-            .conn
-            .lock()
-            .unwrap()
+            .db
+            .get()
             .prepare(sql)?
             .query_map(params, |row| {
                 // TODO: Extract this into a function.
@@ -346,7 +341,7 @@ async fn room_create(
         ));
     }
 
-    let mut conn = st.conn.lock().unwrap();
+    let mut conn = st.db.get();
     let Some(true) = conn
         .query_row(
             r"
@@ -450,7 +445,7 @@ async fn room_get_item(
     OptionalAuth(user): OptionalAuth,
 ) -> Result<Json<RoomItems>, ApiError> {
     let (items, skip_token) = {
-        let conn = st.conn.lock().unwrap();
+        let conn = st.db.get();
         get_room_if_readable(&conn, ruuid, user.as_ref(), |_row| Ok(()))?;
         query_room_items(&st, &conn, ruuid, pagination)?
     };
@@ -466,13 +461,12 @@ async fn room_get_metadata(
     WithRejection(Path(ruuid), _): WithRejection<Path<Uuid>, ApiError>,
     OptionalAuth(user): OptionalAuth,
 ) -> Result<Json<RoomMetadata>, ApiError> {
-    let (title, attrs) =
-        get_room_if_readable(&st.conn.lock().unwrap(), ruuid, user.as_ref(), |row| {
-            Ok((
-                row.get::<_, String>("title")?,
-                row.get::<_, RoomAttrs>("attrs")?,
-            ))
-        })?;
+    let (title, attrs) = get_room_if_readable(&st.db.get(), ruuid, user.as_ref(), |row| {
+        Ok((
+            row.get::<_, String>("title")?,
+            row.get::<_, RoomAttrs>("attrs")?,
+        ))
+    })?;
 
     Ok(Json(RoomMetadata {
         ruuid,
@@ -489,7 +483,7 @@ async fn room_get_feed(
 ) -> Result<impl IntoResponse, ApiError> {
     let title;
     let (items, skip_token) = {
-        let conn = st.conn.lock().unwrap();
+        let conn = st.db.get();
         title = get_room_if_readable(&conn, ruuid, None, |row| row.get::<_, String>("title"))?;
         query_room_items(&st, &conn, ruuid, pagination)?
     };
@@ -690,7 +684,7 @@ async fn room_post_item(
     }
 
     let (cid, txs) = {
-        let conn = st.conn.lock().unwrap();
+        let conn = st.db.get();
         let Some((rid, uid)) = conn
             .query_row(
                 r"
@@ -820,7 +814,7 @@ async fn room_join(
     user: UserKey,
     permission: MemberPermission,
 ) -> Result<(), ApiError> {
-    let mut conn = st.conn.lock().unwrap();
+    let mut conn = st.db.get();
     let txn = conn.transaction()?;
     let Some(rid) = txn
         .query_row(
@@ -872,7 +866,7 @@ async fn room_join(
 }
 
 async fn room_leave(st: &AppState, ruuid: Uuid, user: UserKey) -> Result<(), ApiError> {
-    let mut conn = st.conn.lock().unwrap();
+    let mut conn = st.db.get();
     let txn = conn.transaction()?;
 
     let Some((rid, uid)) = txn