firewalldb: introduce DBExecutor and use it for KVStores

Here we introduce a generic DBExecutor interface with methods that take
a generic T transaction. This is in preparation for the introducing a
SQL transaction instead of a bolt one.

Author: ellemouton

firewalldb/interface.go

@@ -14,3 +14,24 @@ type SessionDB interface {
 	// GetSession returns the session for a specific id.
 	GetSession(context.Context, session.ID) (*session.Session, error)
 }
+
+// DBExecutor provides an Update and View method that will allow the caller
+// to perform atomic read and write transactions defined by PrivacyMapTx on the
+// underlying BoltDB.
+type DBExecutor[T any] interface {
+	// Update opens a database read/write transaction and executes the
+	// function f with the transaction passed as a parameter. After f exits,
+	// if f did not error, the transaction is committed. Otherwise, if f did
+	// error, the transaction is rolled back. If the rollback fails, the
+	// original error returned by f is still returned. If the commit fails,
+	// the commit error is returned.
+	Update(ctx context.Context, f func(ctx context.Context,
+		tx T) error) error
+
+	// View opens a database read transaction and executes the function f
+	// with the transaction passed as a parameter. After f exits, the
+	// transaction is rolled back. If f errors, its error is returned, not a
+	// rollback error (if any occur).
+	View(ctx context.Context, f func(ctx context.Context,
+		tx T) error) error
+}

firewalldb/kvstores.go

@@ -54,23 +54,7 @@ var (
 // KVStores provides an Update and View method that will allow the caller to
 // perform atomic read and write transactions on and of the key value stores
 // offered the KVStoreTx.
-type KVStores interface {
-	// Update opens a database read/write transaction and executes the
-	// function f with the transaction passed as a parameter. After f exits,
-	// if f did not error, the transaction is committed. Otherwise, if f did
-	// error, the transaction is rolled back. If the rollback fails, the
-	// original error returned by f is still returned. If the commit fails,
-	// the commit error is returned.
-	Update(ctx context.Context, f func(ctx context.Context,
-		tx KVStoreTx) error) error
-
-	// View opens a database read transaction and executes the function f
-	// with the transaction passed as a parameter. After f exits, the
-	// transaction is rolled back. If f errors, its error is returned, not a
-	// rollback error (if any occur).
-	View(ctx context.Context, f func(ctx context.Context,
-		tx KVStoreTx) error) error
-}
+type KVStores = DBExecutor[KVStoreTx]
 
 // KVStoreTx represents a database transaction that can be used for both read
 // and writes of the various different key value stores offered for the rule.