db: Add setup and teardown function to DB

These are used to do one-time initializations and wait for pending statements
before closing.

Signed-off-by: Christian Decker <decker.christian@gmail.com>

tests/test_plugin.py

@@ -299,10 +299,9 @@ def test_db_hook(node_factory, executor):
     # It should see the db being created, and sometime later actually get
     # initted.
     # This precedes startup, so needle already past
-    assert l1.daemon.is_in_log('plugin-dblog.py deferring 1 commands')
+    assert l1.daemon.is_in_log(r'plugin-dblog.py deferring \d+ commands')
     l1.daemon.logsearch_start = 0
     l1.daemon.wait_for_log('plugin-dblog.py replaying pre-init data:')
-    l1.daemon.wait_for_log('plugin-dblog.py PRAGMA foreign_keys = ON;')
     l1.daemon.wait_for_log('plugin-dblog.py CREATE TABLE version \\(version INTEGER\\)')
     l1.daemon.wait_for_log("plugin-dblog.py initialized.* 'startup': True")
 

wallet/db.c

@@ -826,10 +826,17 @@ static void setup_open_db(struct db *db)
 	assert(!db->in_transaction);
 
 	db_prepare_for_changes(db);
-	db_do_exec(__func__, db, "PRAGMA foreign_keys = ON;");
+	if (db->config->setup_fn)
+		db->config->setup_fn(db);
 	db_report_changes(db, NULL, 0);
 }
 
+void db_close(struct db *db)
+{
+	if (db->config->teardown_fn)
+		db->config->teardown_fn(db);
+}
+
 /**
  * db_open - Open or create a sqlite3 database
  */

wallet/db.h

@@ -242,6 +242,8 @@ void sqlite3_bind_timeabs(sqlite3_stmt *stmt, int col, struct timeabs t);
 struct timeabs sqlite3_column_timeabs(sqlite3_stmt *stmt, int col);
 
 
+void db_close(struct db *db);
+
 void db_bind_null(struct db_stmt *stmt, int pos);
 void db_bind_int(struct db_stmt *stmt, int pos, int val);
 void db_bind_u64(struct db_stmt *stmt, int pos, u64 val);

wallet/db_common.h

@@ -124,6 +124,9 @@ struct db_config {
 	s64 (*column_int_fn)(struct db_stmt *stmt, int col);
 
 	size_t (*count_changes_fn)(struct db_stmt *stmt);
+
+	bool (*setup_fn)(struct db *db);
+	void (*teardown_fn)(struct db *db);
 };
 
 /* Provide a way for DB backends to register themselves */

wallet/db_sqlite3.c

@@ -28,6 +28,16 @@ static const char *db_sqlite3_fmt_error(struct db_stmt *stmt)
 		       sqlite3_errmsg(stmt->db->conn));
 }
 
+static bool db_sqlite3_setup(struct db *db)
+{
+	sqlite3_stmt *stmt;
+	int err;
+	sqlite3_prepare_v2(db->conn, "PRAGMA foreign_keys = ON;", -1, &stmt, NULL);
+	err = sqlite3_step(stmt);
+	sqlite3_finalize(stmt);
+	return err == SQLITE_DONE;
+}
+
 static bool db_sqlite3_query(struct db_stmt *stmt)
 {
 	sqlite3_stmt *s;
@@ -173,6 +183,11 @@ static size_t db_sqlite3_count_changes(struct db_stmt *stmt)
 	return sqlite3_changes(s);
 }
 
+static void db_sqlite3_close(struct db *db)
+{
+	sqlite3_close(db->sql);
+}
+
 struct db_config db_sqlite3_config = {
 	.name = "sqlite3",
 	.queries = db_sqlite3_queries,
@@ -193,6 +208,8 @@ struct db_config db_sqlite3_config = {
 	.column_text_fn = &db_sqlite3_column_text,
 
 	.count_changes_fn = &db_sqlite3_count_changes,
+	.setup_fn = &db_sqlite3_setup,
+	.teardown_fn = &db_sqlite3_close,
 };
 
 AUTODATA(db_backends, &db_sqlite3_config);