Run SQLite in WAL mode with a busy timeout the driver reads (closes #123)

The default database URL asked for WAL mode with `_journal_mode` and
`_busy_timeout`, which the SQLite driver does not read, so the database
ran in rollback-journal mode. The default now uses the driver's
`_pragma=journal_mode(WAL)` and `_pragma=busy_timeout(5000)` parameters,
in one constant that both the config default and the database fallback
use. The database no longer sets its own busy timeout after opening, so
the URL's value applies. A new test opens a file database with those
parameters through db.New and checks the journal mode and busy timeout.
README.md's database text now matches, and an in-memory test database
drops the same ignored parameter.

Model: opus-5-5
Co-authored-by: clawbot <sneak+clawbot@sneak.cloud>

internal/db/db.go

@@ -87,7 +87,7 @@ func (database *Database) GetDB() *sql.DB {
 func (database *Database) connect(ctx context.Context) error {
 	dbURL := database.params.Config.DBURL
 	if dbURL == "" {
-		dbURL = "file:///var/lib/neoirc/state.db?_journal_mode=WAL&_busy_timeout=5000"
+		dbURL = config.DefaultDBURL
 	}
 
 	database.log.Info(
@@ -116,13 +116,6 @@ func (database *Database) connect(ctx context.Context) error {
 		return fmt.Errorf("enable foreign keys: %w", err)
 	}
 
-	_, err = database.conn.ExecContext(
-		ctx, "PRAGMA busy_timeout = 5000",
-	)
-	if err != nil {
-		return fmt.Errorf("set busy timeout: %w", err)
-	}
-
 	return database.runMigrations(ctx)
 }
 

internal/db/db_test.go

@@ -0,0 +1,75 @@
+package db_test
+
+import (
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"go.uber.org/fx/fxtest"
+	"sneak.berlin/go/neoirc/internal/config"
+	"sneak.berlin/go/neoirc/internal/db"
+	"sneak.berlin/go/neoirc/internal/globals"
+	"sneak.berlin/go/neoirc/internal/logger"
+)
+
+const wantBusyTimeoutMS = 5000
+
+// TestDefaultDBURLSetsWALAndBusyTimeout opens a file database
+// with the default URL's parameters the way the server does,
+// and checks the journal mode and busy timeout it ends up with.
+func TestDefaultDBURLSetsWALAndBusyTimeout(t *testing.T) {
+	t.Parallel()
+
+	_, params, _ := strings.Cut(config.DefaultDBURL, "?")
+	dbURL := "file://" + filepath.Join(t.TempDir(), "state.db") +
+		"?" + params
+
+	lifecycle := fxtest.NewLifecycle(t)
+
+	log, err := logger.New(lifecycle, logger.Params{
+		Globals: &globals.Globals{},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	database, err := db.New(lifecycle, db.Params{
+		Logger: log,
+		Config: &config.Config{DBURL: dbURL},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	lifecycle.RequireStart()
+	t.Cleanup(lifecycle.RequireStop)
+
+	var journalMode string
+
+	err = database.GetDB().QueryRowContext(
+		t.Context(), "PRAGMA journal_mode",
+	).Scan(&journalMode)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if journalMode != "wal" {
+		t.Errorf("journal_mode = %q, want %q", journalMode, "wal")
+	}
+
+	var busyTimeout int
+
+	err = database.GetDB().QueryRowContext(
+		t.Context(), "PRAGMA busy_timeout",
+	).Scan(&busyTimeout)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if busyTimeout != wantBusyTimeoutMS {
+		t.Errorf(
+			"busy_timeout = %d, want %d",
+			busyTimeout, wantBusyTimeoutMS,
+		)
+	}
+}