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db.go
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db.go
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// Package db 提供 mysql 封装
package db
import (
"context"
"database/sql"
"strings"
"sync"
"time"
"github.com/learninto/goutil/conf"
"github.com/learninto/goutil/errors"
"github.com/learninto/goutil/log"
"github.com/learninto/goutil/metrics"
"github.com/dlmiddlecote/sqlstats"
"github.com/go-sql-driver/mysql"
opentracing "github.com/opentracing/opentracing-go"
"github.com/opentracing/opentracing-go/ext"
"github.com/prometheus/client_golang/prometheus"
)
var dbs = make(map[string]*DB, 4)
var lock = sync.RWMutex{}
type Row interface {
Scan(dest ...interface{}) error
}
// DB 对象,有限开放 sql.DB 功能,支持上报 metrics
type DB struct {
db *sql.DB
name string
s sql.DBStats
}
// Query sql 查询对象
type Query struct {
table string
sql string
sqlType string
}
// 清理分表中的数字,否则上报的指标太多,prometheus 算不出来,而且也不好统计
func (q *Query) trimTableNum() string {
return strings.TrimRight(q.table, "0123456789")
}
// Conn 简单 DB 接口。用于统一非事务和事务业务逻辑
type Conn interface {
ExecContext(ctx context.Context, query Query, args ...interface{}) (sql.Result, error)
QueryContext(ctx context.Context, query Query, args ...interface{}) (*sql.Rows, error)
QueryRowContext(ctx context.Context, query Query, args ...interface{}) *sql.Row
}
type unionDB interface {
ExecContext(ctx context.Context, query string, args ...interface{}) (sql.Result, error)
QueryContext(ctx context.Context, query string, args ...interface{}) (*sql.Rows, error)
QueryRowContext(ctx context.Context, query string, args ...interface{}) *sql.Row
}
// SQLInsert 构造 insert 查询
func SQLInsert(table string, sql string) Query {
return Query{
table: table,
sql: sql,
sqlType: "INSERT",
}
}
// SQLDelete 构造 delete 查询
func SQLDelete(table string, sql string) Query {
return Query{
table: table,
sql: sql,
sqlType: "DELETE",
}
}
// SQLUpdate 构造 update 查询
func SQLUpdate(table string, sql string) Query {
return Query{
table: table,
sql: sql,
sqlType: "UPDATE",
}
}
// SQLSelect 构造 select 查询
func SQLSelect(table string, sql string) Query {
return Query{
table: table,
sql: sql,
sqlType: "SELECT",
}
}
// Get 根据配置名字创建并返回 DB 连接池对象
//
// DB 配置名字格式为 DB_{$name}_DSN
// DB 配置内容格式请参考 https://github.com/go-sql-driver/mysql#dsn-data-source-name
// Get 是并发安全的,可以在多协程下使用
func Get(ctx context.Context, name string) *DB {
lock.RLock()
db := dbs[name]
lock.RUnlock()
if db != nil {
return db
}
dsn := conf.Get("DB_" + name + "_DSN")
sqldb, err := sql.Open("mysql", dsn)
if err != nil {
logger := log.Get(ctx)
logger.Panic(err)
}
// 不能设太多,数据库最大连接数总共不宜超过 2k
maxOpenConns := conf.GetInt("DB_" + name + "_MAX_OPEN_CONNS")
if maxOpenConns == 0 {
maxOpenConns = 20
}
sqldb.SetMaxOpenConns(maxOpenConns)
sqldb.SetMaxIdleConns(10)
sqldb.SetConnMaxLifetime(1 * time.Hour)
prometheus.Register(sqlstats.NewStatsCollector(name, sqldb))
db = &DB{db: sqldb, name: name}
lock.Lock()
dbs[name] = db
lock.Unlock()
return db
}
// Reset 关闭所有 DB 连接
// 新调用 Get 方法时会使用最新 DB 配置创建连接
//
// 如果在配置中开启 HOT_LOAD_DB 开关,则每次下发配置都会重置 DB 连接!
func Reset() {
if !conf.GetBool("HOT_LOAD_DB") {
return
}
lock.Lock()
oldDBs := dbs
dbs = make(map[string]*DB, 4)
lock.Unlock()
for k, db := range oldDBs {
db.db.Close()
delete(dbs, k)
}
}
// ExecContext 执行查询,无返回数据
func (db *DB) ExecContext(ctx context.Context, query Query, args ...interface{}) (sql.Result, error) {
return execContext(ctx, db.name, db.db, query, args)
}
func execContext(ctx context.Context, name string, db unionDB, query Query, args []interface{}) (sql.Result, error) {
span, ctx := opentracing.StartSpanFromContext(ctx, "ExecContext")
defer span.Finish()
span.SetTag(string(ext.Component), "mysql")
span.SetTag(string(ext.DBInstance), name)
span.SetTag(string(ext.DBStatement), query.sql)
start := time.Now()
r, err := db.ExecContext(ctx, query.sql, args...)
duration := time.Since(start)
cost := duration.Seconds()
logger := log.Get(ctx)
logger.WithField("cost", cost).Debugf("[DB] name:%s sql:%s args:%v", name, query.sql, args)
metrics.DBDurationsSeconds.WithLabelValues(
name,
query.trimTableNum(),
query.sqlType,
).Observe(cost)
return r, errors.Wrap(err)
}
// QueryContext 执行查询,返回多行数据
func (db *DB) QueryContext(ctx context.Context, query Query, args ...interface{}) (*sql.Rows, error) {
return queryContext(ctx, db.name, db.db, query, args)
}
func queryContext(ctx context.Context, name string, db unionDB, query Query, args []interface{}) (*sql.Rows, error) {
span, ctx := opentracing.StartSpanFromContext(ctx, "QueryContext")
defer span.Finish()
span.SetTag(string(ext.Component), "mysql")
span.SetTag(string(ext.DBInstance), name)
span.SetTag(string(ext.DBStatement), query.sql)
start := time.Now()
r, err := db.QueryContext(ctx, query.sql, args...)
duration := time.Since(start)
cost := duration.Seconds()
logger := log.Get(ctx)
logger.WithField("cost", cost).Debugf("[DB] name:%s sql:%s args:%v", name, query.sql, args)
metrics.DBDurationsSeconds.WithLabelValues(
name,
query.trimTableNum(),
query.sqlType,
).Observe(cost)
return r, errors.Wrap(err)
}
// QueryRowContext 执行查询,至多返回一行数据
func (db *DB) QueryRowContext(ctx context.Context, query Query, args ...interface{}) *sql.Row {
return queryRowContext(ctx, db.name, db.db, query, args)
}
func queryRowContext(ctx context.Context, name string, db unionDB, query Query, args []interface{}) *sql.Row {
span, ctx := opentracing.StartSpanFromContext(ctx, "QueryRowContext")
defer span.Finish()
span.SetTag(string(ext.Component), "mysql")
span.SetTag(string(ext.DBInstance), name)
span.SetTag(string(ext.DBStatement), query.sql)
start := time.Now()
r := db.QueryRowContext(ctx, query.sql, args...)
duration := time.Since(start)
cost := duration.Seconds()
logger := log.Get(ctx)
logger.WithField("cost", cost).Debugf("[DB] name:%s sql:%s args:%v", name, query.sql, args)
metrics.DBDurationsSeconds.WithLabelValues(
name,
query.trimTableNum(),
query.sqlType,
).Observe(cost)
return r
}
// Tx 事务对象简单封装
type Tx struct {
tx *sql.Tx
db string
start time.Time
sqls []string
args [][]interface{}
}
func newTx(ctx context.Context, tx *sql.Tx, db string) *Tx {
return &Tx{
db: db,
tx: tx,
start: time.Now(),
}
}
// msg 目前仅有 commit 和 rollback 两种
func (tx *Tx) log(ctx context.Context, msg string) {
duration := time.Since(tx.start)
logger := log.Get(ctx)
if msg == "commit" {
logger.Debugf("commit, total cost:%s", duration)
} else {
logger.Warnf("rollback, total cost:%s", duration)
}
metrics.DBDurationsSeconds.WithLabelValues(
tx.db,
"_tx",
msg,
).Observe(duration.Seconds())
}
// ExecContext 执行写查询
// 不鼓励在事务中使用读查询,所以只提供 ExecContext 方法
// 框架会根据返回错误自动提交或者回滚,所以不提供相应方法
func (tx *Tx) ExecContext(ctx context.Context, query Query, args ...interface{}) (sql.Result, error) {
return execContext(ctx, tx.db, tx.tx, query, args)
}
// QueryContext 在事务中查询多行数据
func (tx *Tx) QueryContext(ctx context.Context, query Query, args ...interface{}) (*sql.Rows, error) {
return queryContext(ctx, tx.db, tx.tx, query, args)
}
// QueryRowContext 在事务中查询单行数据
func (tx *Tx) QueryRowContext(ctx context.Context, query Query, args ...interface{}) *sql.Row {
return queryRowContext(ctx, tx.db, tx.tx, query, args)
}
func (tx *Tx) rollback(ctx context.Context) error {
tx.log(ctx, "rollback")
if err := tx.tx.Rollback(); err != nil {
return errors.Wrap(err)
}
return nil
}
func (tx *Tx) commit(ctx context.Context) error {
tx.log(ctx, "commit")
if err := tx.tx.Commit(); err != nil {
return errors.Wrap(err)
}
return nil
}
// TxFunc 事务函数,返回 err 会回滚未提交事务,否则自动提交事务
type TxFunc func(ctx context.Context, tx Conn) error
// ExecTx 执行一次事务,回调函数返回 err 或者 panic 或者 ctx 取消都会回滚事务。
// 返回的 err 为 Commit 或者 Rollback 的错误
func (db *DB) ExecTx(ctx context.Context, f TxFunc) error {
span, ctx := opentracing.StartSpanFromContext(ctx, "ExecTx")
defer span.Finish()
span.SetTag(string(ext.Component), "mysql")
tx, err := db.db.BeginTx(ctx, nil)
if err != nil {
return errors.Wrap(err)
}
logger := log.Get(ctx)
logger.Info("BeginTx")
mytx := newTx(ctx, tx, db.name)
defer func() {
if p := recover(); p != nil {
mytx.rollback(ctx)
panic(p)
}
}()
if err := f(ctx, mytx); err != nil {
if err := mytx.rollback(ctx); err != nil {
logger.Error("rollback failed", err)
}
return err
}
return mytx.commit(ctx)
}
// IsNoRowsErr 判断是否为 ErrNoRows 错误
func IsNoRowsErr(err error) bool {
if err == nil {
return false
}
return errors.Cause(err) == sql.ErrNoRows
}
// IsDuplicateEntryErr 判断是否为唯一键冲突错误
func IsDuplicateEntryErr(err error) bool {
if err == nil {
return false
}
// https://stackoverflow.com/a/41666013
if me, ok := errors.Cause(err).(*mysql.MySQLError); ok {
return me.Number == 1062
}
return false
}