Enable database WAL

CHANGELOG.md

@@ -9,6 +9,7 @@
 
 - **(app)** **(breaking)** Browsers without the [ResizeObserver API](https://caniuse.com/#feat=mdn-api_resizeobserver) are no longer supported
 - **(server)** Uses one less process/helper
+- **(server)** Media scanner performance is greatly improved when adding media
 - **(server)** Media scanner process is restricted to read-only database access
 - **(server)** Fixed potential error when a non-admin user tries to remove one of their queued songs
 - **(server)** Fixed potential SQLITE_BUSY errors while scanning media

server/lib/Database.js

@@ -6,7 +6,16 @@ let _db
 
 class Database {
   static async close () {
-    // @todo
+    // depending on how the node process was started, it can receive
+    // multiple SIGINTs or SIGTERMs in the same tick, so we clear the
+    // reference first to avoid calling close() multiple times
+    if (_db) {
+      const db = _db
+      _db = null
+
+      log.info('Closing database file %s', db.config.filename)
+      await db.close()
+    }
   }
 
   static async open ({ readonly = true, env = process.env } = {}) {
@@ -25,6 +34,8 @@ class Database {
       await db.migrate({
         migrationsPath: path.join(__dirname, 'schemas'),
       })
+
+      await db.run('PRAGMA journal_mode = WAL;')
     }
 
     _db = db

server/main.js

@@ -18,14 +18,18 @@ const {
 
 Object.keys(env).forEach(key => log.verbose(`${key} = ${env[key]}`))
 
+// close db before exiting (can't do async in the 'exit' handler)
+process.on('SIGTERM', shutdown)
+process.on('SIGINT', shutdown)
+
 // make sure child processes don't hang around
 process.on('exit', function () {
   if (refs.scanner) refs.scanner.kill()
 })
 
 // debug: log stack trace for unhandled promise rejections
 process.on('unhandledRejection', (reason, p) => {
-  log.error('Unhandled Rejection at: Promise', p, 'reason:', reason)
+  log.error('Unhandled Rejection:', p, 'reason:', reason)
 })
 
 // detect electron
@@ -80,3 +84,12 @@ function stopScanner () {
     IPC.send({ type: SCANNER_CMD_STOP })
   }
 }
+
+function shutdown (signal) {
+  log.info('Received signal %s', signal)
+
+  Database.close().then(() => {
+    log.info('Goodbye for now...')
+    process.exit(0)
+  })
+}