feat: allow passing extra parameters to sqlite conn string

Do not expose the base parameters, as they are required for COSI to work correctly.

Add a flag for the additional parameters, which can for example be used for configuring the SQLite db to be "suitable" for litestream to be able to make backups of it.

Also, add `_pragma=synchronous(NORMAL)` to the base parameters, as it is recommended for better performance when WAL mode is enabled.

Signed-off-by: Utku Ozdemir <[email protected]>

Author: utkuozdemir

cmd/omni/cmd/cmd.go

@@ -24,6 +24,7 @@ import (
 	"github.com/siderolabs/omni/client/pkg/panichandler"
 	"github.com/siderolabs/omni/cmd/omni/pkg/app"
 	"github.com/siderolabs/omni/internal/backend/runtime/omni"
+	"github.com/siderolabs/omni/internal/backend/runtime/omni/sqlite"
 	"github.com/siderolabs/omni/internal/pkg/auth/actor"
 	"github.com/siderolabs/omni/internal/pkg/config"
 	"github.com/siderolabs/omni/internal/version"
@@ -629,6 +630,13 @@ func defineStorageFlags() {
 		cmdConfig.Storage.SQLite.Path,
 		"path of the file for sqlite-backed secondary storage for frequently updated data, machine and audit logs.",
 	)
+	rootCmd.Flags().StringVar(
+		&cmdConfig.Storage.SQLite.ExtraParams,
+		"sqlite-storage-extra-params",
+		cmdConfig.Storage.SQLite.ExtraParams,
+		fmt.Sprintf("extra DSN (connection string) parameters for sqlite database connection. "+
+			"they will be appended to base params of %q. they must not start with ampersand (&).", sqlite.BaseParams),
+	)
 }
 
 func defineRegistriesFlags() {

internal/backend/runtime/omni/sqlite/sqlite.go

@@ -0,0 +1,37 @@
+// Copyright (c) 2025 Sidero Labs, Inc.
+//
+// Use of this software is governed by the Business Source License
+// included in the LICENSE file.
+
+package sqlite
+
+import (
+	"database/sql"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/siderolabs/omni/internal/pkg/config"
+)
+
+// BaseParams are the base DSN parameters used for SQLite connections.
+const BaseParams = "_txlock=immediate&_pragma=busy_timeout(50000)&_pragma=journal_mode(WAL)&_pragma=synchronous(NORMAL)"
+
+// OpenDB opens a SQLite database with the given configuration.
+func OpenDB(config config.SQLite) (*sql.DB, error) {
+	if err := os.MkdirAll(filepath.Dir(config.Path), 0o755); err != nil {
+		return nil, fmt.Errorf("failed to create directory for sqlite database %q: %w", config.Path, err)
+	}
+
+	dsn := "file:" + config.Path + "?" + BaseParams
+	if config.ExtraParams != "" {
+		dsn += "&" + config.ExtraParams
+	}
+
+	db, err := sql.Open("sqlite", dsn)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open sqlite database %q: %w", dsn, err)
+	}
+
+	return db, nil
+}

internal/backend/runtime/omni/state.go

@@ -127,7 +127,7 @@ func NewState(ctx context.Context, params *config.Params, logger *zap.Logger, me
 	virtualState := virtual.NewState(state.WrapCore(defaultPersistentState.State))
 
 	secondaryPersistentState, err := newSQLitePersistentState(
-		ctx, params.Storage.SQLite.Path, logger)
+		ctx, params.Storage.SQLite, logger)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create SQLite state for secondary storage: %w", err)
 	}

internal/backend/runtime/omni/state_sqlite.go

@@ -7,10 +7,8 @@ package omni
 
 import (
 	"context"
-	"database/sql"
 	"fmt"
 	"os"
-	"path/filepath"
 
 	"github.com/cosi-project/runtime/pkg/resource"
 	"github.com/cosi-project/runtime/pkg/state"
@@ -22,18 +20,14 @@ import (
 
 	"github.com/siderolabs/omni/client/pkg/omni/resources"
 	"github.com/siderolabs/omni/client/pkg/omni/resources/omni"
+	omnisqlite "github.com/siderolabs/omni/internal/backend/runtime/omni/sqlite"
+	"github.com/siderolabs/omni/internal/pkg/config"
 )
 
-func newSQLitePersistentState(ctx context.Context, path string, logger *zap.Logger) (*PersistentState, error) {
-	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
-		return nil, fmt.Errorf("failed to create directory for sqlite database %q: %w", path, err)
-	}
-
-	dsn := "file:" + path + "?_txlock=immediate&_pragma=busy_timeout(50000)&_pragma=journal_mode(WAL)"
-
-	db, err := sql.Open("sqlite", dsn)
+func newSQLitePersistentState(ctx context.Context, config config.SQLite, logger *zap.Logger) (*PersistentState, error) {
+	db, err := omnisqlite.OpenDB(config)
 	if err != nil {
-		return nil, fmt.Errorf("failed to open sqlite database %q: %w", dsn, err)
+		return nil, err
 	}
 
 	st, err := sqlite.NewState(ctx, db, store.ProtobufMarshaler{},
@@ -43,7 +37,7 @@ func newSQLitePersistentState(ctx context.Context, path string, logger *zap.Logg
 	if err != nil {
 		db.Close() //nolint:errcheck
 
-		return nil, fmt.Errorf("failed to create sqlite state (database %q): %w", dsn, err)
+		return nil, fmt.Errorf("failed to create sqlite state (path %q): %w", config.Path, err)
 	}
 
 	return &PersistentState{

internal/pkg/config/storage.go

@@ -45,7 +45,8 @@ type BoltDB struct {
 
 // SQLite defines sqlite storage configs.
 type SQLite struct {
-	Path string `yaml:"path"`
+	Path        string `yaml:"path"`
+	ExtraParams string `yaml:"extraParams"`
 }
 
 // EtcdParams defines etcd storage configs.