db: modify mysql/pg/sqlite interface for pool working (#24780)

vlib/db/mysql/mysql.c.v

@@ -330,12 +330,10 @@ pub fn (mut db DB) refresh(options u32) !bool {
 }
 
 // reset resets the connection, and clear the session state.
-pub fn (mut db DB) reset() !bool {
+pub fn (mut db DB) reset() ! {
 	if C.mysql_reset_connection(db.conn) != 0 {
 		db.throw_mysql_error()!
 	}
-
-	return true
 }
 
 // ping pings a server connection, or tries to reconnect if the connection
@@ -348,8 +346,14 @@ pub fn (mut db DB) ping() !bool {
 	return true
 }
 
+// validate pings a server connection, or tries to reconnect if the connection
+// has gone down.
+pub fn (mut db DB) validate() !bool {
+	return db.ping()!
+}
+
 // close closes the connection.
-pub fn (mut db DB) close() {
+pub fn (mut db DB) close() ! {
 	C.mysql_close(db.conn)
 }
 

vlib/db/mysql/mysql_orm_test.v

@@ -58,7 +58,7 @@ fn test_mysql_orm() {
 		dbname:   'mysql'
 	)!
 	defer {
-		db.close()
+		db.close() or {}
 	}
 	table := orm.Table{
 		name: 'Test'

vlib/db/mysql/mysql_test.v

@@ -16,6 +16,11 @@ fn test_mysql() {
 	}
 
 	mut db := mysql.connect(config)!
+	defer {
+		db.close() or {}
+	}
+
+	assert db.validate()!
 
 	mut response := db.exec('drop table if exists users')!
 	assert response == []mysql.Row{}

vlib/db/mysql/pool.v

@@ -33,6 +33,6 @@ pub fn (mut pool ConnectionPool) release(conn DB) {
 pub fn (mut pool ConnectionPool) close() {
 	for _ in 0 .. pool.connections.len {
 		mut conn := <-pool.connections or { break }
-		conn.close()
+		conn.close() or { break }
 	}
 }

vlib/db/pg/pg.c.v

@@ -224,7 +224,7 @@ fn res_to_rows(res voidptr) []Row {
 }
 
 // close frees the underlying resource allocated by the database connection
-pub fn (db &DB) close() {
+pub fn (db &DB) close() ! {
 	C.PQfinish(db.conn)
 }
 
@@ -510,3 +510,13 @@ pub fn (db &DB) savepoint(savepoint string) ! {
 		return error('pg exec error: "${e}"')
 	}
 }
+
+// validate checks if the connection is still usable
+pub fn (db &DB) validate() !bool {
+	db.exec_one('SELECT 1')!
+	return true
+}
+
+// reset returns the connection to initial state for reuse
+pub fn (db &DB) reset() ! {
+}

vlib/db/pg/pg_double_test.v

@@ -19,7 +19,7 @@ fn test_float_field() {
 	conn := 'host=localhost user=postgres password=12345678' // insert own connection string
 	db := pg.connect_with_conninfo(conn)!
 	defer {
-		db.close()
+		db.close() or {}
 	}
 
 	sql db {

vlib/db/pg/pg_orm_test.v

@@ -57,7 +57,7 @@ fn test_pg_orm() {
 	) or { panic(err) }
 
 	defer {
-		db.close()
+		db.close() or {}
 	}
 	table := orm.Table{
 		name: 'Test'

vlib/db/pg/pg_test.v

@@ -12,9 +12,11 @@ fn test_large_exec() {
 
 	db := pg.connect(pg.Config{ user: 'postgres', password: '12345678', dbname: 'postgres' })!
 	defer {
-		db.close()
+		db.close() or {}
 	}
 
+	assert db.validate()!
+
 	rows := db.exec('
 SELECT ischema.table_schema, c.relname, a.attname, t.typname, t.typalign, t.typlen
   FROM pg_class c
@@ -38,7 +40,7 @@ fn test_prepared() {
 	}
 	db := pg.connect(pg.Config{ user: 'postgres', password: '12345678', dbname: 'postgres' })!
 	defer {
-		db.close()
+		db.close() or {}
 	}
 
 	db.prepare('test_prepared', 'SELECT NOW(), $1 AS NAME', 1) or { panic(err) }
@@ -57,7 +59,7 @@ fn test_transaction() {
 
 	db := pg.connect(pg.Config{ user: 'postgres', password: '12345678', dbname: 'postgres' })!
 	defer {
-		db.close()
+		db.close() or {}
 	}
 	db.exec('drop table if exists users')!
 	db.exec('create table if not exists users (

vlib/db/pg/pool.v

@@ -33,6 +33,6 @@ pub fn (mut pool ConnectionPool) release(conn DB) {
 pub fn (mut pool ConnectionPool) close() {
 	for _ in 0 .. pool.connections.len {
 		conn := <-pool.connections or { break }
-		conn.close()
+		conn.close() or { break }
 	}
 }

vlib/db/sqlite/sqlite.c.v

@@ -150,7 +150,7 @@ pub fn connect(path string) !DB {
 // close Closes the DB.
 // TODO: For all functions, determine whether the connection is
 // closed first, and determine what to do if it is
-pub fn (mut db DB) close() !bool {
+pub fn (mut db DB) close() ! {
 	code := C.sqlite3_close(db.conn)
 	if code == 0 {
 		db.is_open = false
@@ -160,7 +160,6 @@ pub fn (mut db DB) close() !bool {
 			code: code
 		}
 	}
-	return true // successfully closed
 }
 
 // Only for V ORM
@@ -500,3 +499,12 @@ pub fn (mut db DB) rollback_to(savepoint string) ! {
 	}
 	db.exec('ROLLBACK TO ${savepoint};')!
 }
+
+// reset returns the connection to initial state for reuse
+pub fn (mut db DB) reset() ! {
+}
+
+// validate checks if the connection is still usable
+pub fn (mut db DB) validate() !bool {
+	return db.exec_none('SELECT 1') == 100
+}

vlib/db/sqlite/sqlite_test.v

@@ -37,6 +37,7 @@ fn test_sqlite() {
 	}
 	mut db := sqlite.connect(':memory:') or { panic(err) }
 	assert db.is_open
+	assert db.validate()!
 	db.exec('drop table if exists users')!
 	db.exec("create table users (id integer primary key, name text default '', last_name text null default null);")!
 	db.exec("insert into users (name) values ('Sam')")!