mycnf.go

// Copyright 2012, Google Inc. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

/*
  Generate my.cnf files from templates.
*/

package mysqlctl

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"strconv"
)

// Mycnf is a memory structure that contains a bunch of interesting
// parameters to start mysqld. It can be used to generate standard
// my.cnf files from a server id and mysql port. It can also be
// populated from an existing my.cnf, or by command line parameters.
type Mycnf struct {
	// ServerID is the unique id for this server.
	// Used to create a bunch of named directories.
	ServerID uint32

	// MysqlPort is the port for the MySQL server running on this machine.
	// It is mainly used to communicate with topology server.
	MysqlPort int32

	// DataDir is where the table files are
	// (used by vt software for Clone)
	DataDir string

	// InnodbDataHomeDir is the data directory for innodb.
	// (used by vt software for Clone)
	InnodbDataHomeDir string

	// InnodbLogGroupHomeDir is the logs directory for innodb.
	// (used by vt software for Clone)
	InnodbLogGroupHomeDir string

	// SocketFile is the path to the local mysql.sock file.
	// (used by vt software to check server is running)
	SocketFile string

	// ErrorLogPath is the path to store error logs at.
	// (unused by vt software for now)
	ErrorLogPath string

	// SlowLogPath is the slow query log path
	// (unused by vt software for now)
	SlowLogPath string

	// RelayLogPath is the path of the relay logs
	// (unused by vt software for now)
	RelayLogPath string

	// RelayLogIndexPath is the file name for the relay log index
	// (unused by vt software for now)
	RelayLogIndexPath string

	// RelayLogInfoPath is the file name for the relay log info file
	// (unused by vt software for now)
	RelayLogInfoPath string

	// BinLogPath is the base path for binlogs
	// (used by vt software for binlog streaming and rowcache invalidation)
	BinLogPath string

	// MasterInfoFile is the master.info file location.
	// (unused by vt software for now)
	MasterInfoFile string

	// PidFile is the mysql.pid file location
	// (used by vt software to check server is running)
	PidFile string

	// TmpDir is where to create temporary tables
	// (unused by vt software for now)
	TmpDir string

	// SlaveLoadTmpDir is where to create tmp files for replication
	// (unused by vt software for now)
	SlaveLoadTmpDir string

	mycnfMap map[string]string
	path     string // the actual path that represents this mycnf
}

func (cnf *Mycnf) lookupAndCheck(key string) string {
	key = normKey([]byte(key))
	val := cnf.mycnfMap[key]
	if val == "" {
		panic(fmt.Errorf("Value for key '%v' not set", key))
	}
	return val
}

func normKey(bkey []byte) string {
	// FIXME(msolomon) People are careless about hyphen vs underscore - we should normalize.
	// But you have to normalize to hyphen, or mysqld_safe can fail.
	return string(bytes.Replace(bytes.TrimSpace(bkey), []byte("_"), []byte("-"), -1))
}

// ReadMycnf will read an existing my.cnf from disk, and create a Mycnf object.
func ReadMycnf(cnfFile string) (mycnf *Mycnf, err error) {
	defer func(err *error) {
		if x := recover(); x != nil {
			*err = x.(error)
		}
	}(&err)

	f, err := os.Open(cnfFile)
	if err != nil {
		return nil, err
	}
	defer f.Close()

	buf := bufio.NewReader(f)
	mycnf = new(Mycnf)
	mycnf.path, err = filepath.Abs(cnfFile)
	if err != nil {
		return nil, err
	}
	mycnf.mycnfMap = make(map[string]string)
	var lval, rval string
	var parts [][]byte

	for {
		line, _, err := buf.ReadLine()
		if err == io.EOF {
			break
		}
		line = bytes.TrimSpace(line)

		parts = bytes.Split(line, []byte("="))
		if len(parts) < 2 {
			continue
		}
		lval = normKey(parts[0])
		rval = string(bytes.TrimSpace(parts[1]))
		mycnf.mycnfMap[lval] = rval
	}

	serverIDStr := mycnf.lookupAndCheck("server-id")
	serverID, err := strconv.Atoi(serverIDStr)
	if err != nil {
		return nil, fmt.Errorf("Failed to convert server-id %v", err)
	}
	mycnf.ServerID = uint32(serverID)

	portStr := mycnf.lookupAndCheck("port")
	port, err := strconv.Atoi(portStr)
	if err != nil {
		return nil, fmt.Errorf("Failed: failed to convert port %v", err)
	}
	mycnf.MysqlPort = int32(port)
	mycnf.DataDir = mycnf.lookupAndCheck("datadir")
	mycnf.InnodbDataHomeDir = mycnf.lookupAndCheck("innodb_data_home_dir")
	mycnf.InnodbLogGroupHomeDir = mycnf.lookupAndCheck("innodb_log_group_home_dir")
	mycnf.SocketFile = mycnf.lookupAndCheck("socket")
	mycnf.ErrorLogPath = mycnf.lookupAndCheck("log-error")
	mycnf.SlowLogPath = mycnf.lookupAndCheck("slow-query-log-file")
	mycnf.RelayLogPath = mycnf.lookupAndCheck("relay-log")
	mycnf.RelayLogIndexPath = mycnf.lookupAndCheck("relay-log-index")
	mycnf.RelayLogInfoPath = mycnf.lookupAndCheck("relay-log-info-file")
	mycnf.BinLogPath = mycnf.lookupAndCheck("log-bin")
	mycnf.MasterInfoFile = mycnf.lookupAndCheck("master-info-file")
	mycnf.PidFile = mycnf.lookupAndCheck("pid-file")

	return mycnf, nil
}