bootstrap.go

// Copyright 2013 The ql Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSES/QL-LICENSE file.

// Copyright 2015 PingCAP, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.

package tidb

import (
	"fmt"
	"runtime/debug"
	"strings"

	"github.com/juju/errors"
	"github.com/ngaut/log"
	"github.com/pingcap/tidb/mysql"
	"github.com/pingcap/tidb/sessionctx/variable"
	"github.com/pingcap/tidb/terror"
)

const (
	// CreateUserTable is the SQL statement creates User table in system db.
	CreateUserTable = `CREATE TABLE if not exists mysql.user (
		Host			CHAR(64),
		User			CHAR(16),
		Password		CHAR(41),
		Select_priv		ENUM('N','Y') NOT NULL  DEFAULT 'N',
		Insert_priv		ENUM('N','Y') NOT NULL  DEFAULT 'N',
		Update_priv		ENUM('N','Y') NOT NULL  DEFAULT 'N',
		Delete_priv		ENUM('N','Y') NOT NULL  DEFAULT 'N',
		Create_priv		ENUM('N','Y') NOT NULL  DEFAULT 'N',
		Drop_priv		ENUM('N','Y') NOT NULL  DEFAULT 'N',
		Grant_priv		ENUM('N','Y') NOT NULL  DEFAULT 'N',
		Alter_priv		ENUM('N','Y') NOT NULL  DEFAULT 'N',
		Show_db_priv		ENUM('N','Y') NOT NULL  DEFAULT 'N',
		Execute_priv		ENUM('N','Y') NOT NULL  DEFAULT 'N',
		Index_priv		ENUM('N','Y') NOT NULL  DEFAULT 'N',
		Create_user_priv	ENUM('N','Y') NOT NULL  DEFAULT 'N',
		PRIMARY KEY (Host, User));`
	// CreateDBPrivTable is the SQL statement creates DB scope privilege table in system db.
	CreateDBPrivTable = `CREATE TABLE if not exists mysql.db (
		Host		CHAR(60),
		DB		CHAR(64),
		User		CHAR(16),
		Select_priv	ENUM('N','Y') Not Null  DEFAULT 'N',
		Insert_priv	ENUM('N','Y') Not Null  DEFAULT 'N',
		Update_priv	ENUM('N','Y') Not Null  DEFAULT 'N',
		Delete_priv	ENUM('N','Y') Not Null  DEFAULT 'N',
		Create_priv	ENUM('N','Y') Not Null  DEFAULT 'N',
		Drop_priv	ENUM('N','Y') Not Null  DEFAULT 'N',
		Grant_priv	ENUM('N','Y') Not Null  DEFAULT 'N',
		Index_priv	ENUM('N','Y') Not Null  DEFAULT 'N',
		Alter_priv	ENUM('N','Y') Not Null  DEFAULT 'N',
		Execute_priv	ENUM('N','Y') Not Null  DEFAULT 'N',
		PRIMARY KEY (Host, DB, User));`
	// CreateTablePrivTable is the SQL statement creates table scope privilege table in system db.
	CreateTablePrivTable = `CREATE TABLE if not exists mysql.tables_priv (
		Host		CHAR(60),
		DB		CHAR(64),
		User		CHAR(16),
		Table_name	CHAR(64),
		Grantor		CHAR(77),
		Timestamp	Timestamp DEFAULT CURRENT_TIMESTAMP,
		Table_priv	SET('Select','Insert','Update','Delete','Create','Drop','Grant', 'Index','Alter'),
		Column_priv	SET('Select','Insert','Update'),
		PRIMARY KEY (Host, DB, User, Table_name));`
	// CreateColumnPrivTable is the SQL statement creates column scope privilege table in system db.
	CreateColumnPrivTable = `CREATE TABLE if not exists mysql.columns_priv(
		Host		CHAR(60),
		DB		CHAR(64),
		User		CHAR(16),
		Table_name	CHAR(64),
		Column_name	CHAR(64),
		Timestamp	Timestamp DEFAULT CURRENT_TIMESTAMP,
		Column_priv	SET('Select','Insert','Update'),
		PRIMARY KEY (Host, DB, User, Table_name, Column_name));`
	// CreateGloablVariablesTable is the SQL statement creates global variable table in system db.
	// TODO: MySQL puts GLOBAL_VARIABLES table in INFORMATION_SCHEMA db.
	// INFORMATION_SCHEMA is a virtual db in TiDB. So we put this table in system db.
	// Maybe we will put it back to INFORMATION_SCHEMA.
	CreateGloablVariablesTable = `CREATE TABLE if not exists mysql.GLOBAL_VARIABLES(
		VARIABLE_NAME  VARCHAR(64) Not Null PRIMARY KEY,
		VARIABLE_VALUE VARCHAR(1024) DEFAULT Null);`
	// CreateTiDBTable is the SQL statement creates a table in system db.
	// This table is a key-value struct contains some information used by TiDB.
	// Currently we only put bootstrapped in it which indicates if the system is already bootstrapped.
	CreateTiDBTable = `CREATE TABLE if not exists mysql.tidb(
		VARIABLE_NAME  VARCHAR(64) Not Null PRIMARY KEY,
		VARIABLE_VALUE VARCHAR(1024) DEFAULT Null,
		COMMENT VARCHAR(1024));`
)

// Bootstrap initiates system DB for a store.
func bootstrap(s Session) {
	b, err := checkBootstrapped(s)
	if err != nil {
		log.Fatal(err)
	}
	if b {
		return
	}
	doDDLWorks(s)
	doDMLWorks(s)
}

const (
	bootstrappedVar     = "bootstrapped"
	bootstrappedVarTrue = "True"
)

func checkBootstrapped(s Session) (bool, error) {
	//  Check if system db exists.
	_, err := s.Execute(fmt.Sprintf("USE %s;", mysql.SystemDB))
	if err != nil && terror.DatabaseNotExists.NotEqual(err) {
		log.Fatal(err)
	}
	// Check bootstrapped variable value in TiDB table.
	v, err := checkBootstrappedVar(s)
	if err != nil {
		return false, errors.Trace(err)
	}
	return v, nil
}

func checkBootstrappedVar(s Session) (bool, error) {
	sql := fmt.Sprintf(`SELECT VARIABLE_VALUE FROM %s.%s WHERE VARIABLE_NAME="%s"`, mysql.SystemDB, mysql.TiDBTable, bootstrappedVar)
	rs, err := s.Execute(sql)
	if err != nil {
		if terror.TableNotExists.Equal(err) {
			return false, nil
		}
		return false, errors.Trace(err)
	}
	if len(rs) != 1 {
		return false, errors.New("Wrong number of Recordset")
	}
	r := rs[0]
	row, err := r.Next()
	if err != nil || row == nil {
		return false, errors.Trace(err)
	}
	return row.Data[0].(string) == bootstrappedVarTrue, nil
}

// Execute DDL statements in bootstrap stage.
func doDDLWorks(s Session) {
	// Create a test database.
	mustExecute(s, "CREATE DATABASE IF NOT EXISTS test")
	// Create system db.
	mustExecute(s, fmt.Sprintf("CREATE DATABASE IF NOT EXISTS %s;", mysql.SystemDB))
	// Create user table.
	mustExecute(s, CreateUserTable)
	// Create privilege tables.
	mustExecute(s, CreateDBPrivTable)
	mustExecute(s, CreateTablePrivTable)
	mustExecute(s, CreateColumnPrivTable)
	// Create global systemt variable table.
	mustExecute(s, CreateGloablVariablesTable)
	// Create TiDB table.
	mustExecute(s, CreateTiDBTable)
}

// Execute DML statements in bootstrap stage.
// All the statements run in a single transaction.
func doDMLWorks(s Session) {
	mustExecute(s, "BEGIN")
	// Insert a default user with empty password.
	mustExecute(s, `INSERT INTO mysql.user VALUES ("localhost", "root", "", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y"), 
		("127.0.0.1", "root", "", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y"), 
		("::1", "root", "", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y", "Y");`)
	// Init global system variable table.
	values := make([]string, 0, len(variable.SysVars))
	for k, v := range variable.SysVars {
		value := fmt.Sprintf(`("%s", "%s")`, strings.ToLower(k), v.Value)
		values = append(values, value)
	}
	sql := fmt.Sprintf("INSERT INTO %s.%s VALUES %s;", mysql.SystemDB, mysql.GlobalVariablesTable, strings.Join(values, ", "))
	mustExecute(s, sql)
	sql = fmt.Sprintf(`INSERT INTO %s.%s VALUES("%s", "%s", "Bootstrap flag. Do not delete.") ON DUPLICATE KEY UPDATE VARIABLE_VALUE="%s"`, mysql.SystemDB, mysql.TiDBTable, bootstrappedVar, bootstrappedVarTrue, bootstrappedVarTrue)
	mustExecute(s, sql)
	mustExecute(s, "COMMIT")
}

func mustExecute(s Session, sql string) {
	_, err := s.Execute(sql)
	if err != nil {
		debug.PrintStack()
		log.Fatal(err)
	}
}