/
sql.go
676 lines (630 loc) · 18.8 KB
/
sql.go
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package sql
import (
"context"
"database/sql"
"fmt"
"sync/atomic"
"time"
"github.com/go-kratos/kratos/pkg/ecode"
"github.com/go-kratos/kratos/pkg/log"
"github.com/go-kratos/kratos/pkg/net/netutil/breaker"
"github.com/go-kratos/kratos/pkg/net/trace"
"github.com/go-sql-driver/mysql"
"github.com/pkg/errors"
)
const (
_family = "sql_client"
_slowLogDuration = time.Millisecond * 250
)
var (
// ErrStmtNil prepared stmt error
ErrStmtNil = errors.New("sql: prepare failed and stmt nil")
// ErrNoMaster is returned by Master when call master multiple times.
ErrNoMaster = errors.New("sql: no master instance")
// ErrNoRows is returned by Scan when QueryRow doesn't return a row.
// In such a case, QueryRow returns a placeholder *Row value that defers
// this error until a Scan.
ErrNoRows = sql.ErrNoRows
// ErrTxDone transaction done.
ErrTxDone = sql.ErrTxDone
)
// DB database.
type DB struct {
write *conn
read []*conn
idx int64
master *DB
}
// conn database connection
type conn struct {
*sql.DB
breaker breaker.Breaker
conf *Config
addr string
}
// Tx transaction.
type Tx struct {
db *conn
tx *sql.Tx
t trace.Trace
c context.Context
cancel func()
}
// Row row.
type Row struct {
err error
*sql.Row
db *conn
query string
args []interface{}
t trace.Trace
cancel func()
}
// Scan copies the columns from the matched row into the values pointed at by dest.
func (r *Row) Scan(dest ...interface{}) (err error) {
defer slowLog(fmt.Sprintf("Scan query(%s) args(%+v)", r.query, r.args), time.Now())
if r.t != nil {
defer r.t.Finish(&err)
}
if r.err != nil {
err = r.err
} else if r.Row == nil {
err = ErrStmtNil
}
if err != nil {
return
}
err = r.Row.Scan(dest...)
if r.cancel != nil {
r.cancel()
}
r.db.onBreaker(&err)
if err != ErrNoRows {
err = errors.Wrapf(err, "query %s args %+v", r.query, r.args)
}
return
}
// Rows rows.
type Rows struct {
*sql.Rows
cancel func()
}
// Close closes the Rows, preventing further enumeration. If Next is called
// and returns false and there are no further result sets,
// the Rows are closed automatically and it will suffice to check the
// result of Err. Close is idempotent and does not affect the result of Err.
func (rs *Rows) Close() (err error) {
err = errors.WithStack(rs.Rows.Close())
if rs.cancel != nil {
rs.cancel()
}
return
}
// Stmt prepared stmt.
type Stmt struct {
db *conn
tx bool
query string
stmt atomic.Value
t trace.Trace
}
// Open opens a database specified by its database driver name and a
// driver-specific data source name, usually consisting of at least a database
// name and connection information.
func Open(c *Config) (*DB, error) {
db := new(DB)
d, err := connect(c, c.DSN)
if err != nil {
return nil, err
}
addr := parseDSNAddr(c.DSN)
brkGroup := breaker.NewGroup(c.Breaker)
brk := brkGroup.Get(addr)
w := &conn{DB: d, breaker: brk, conf: c, addr: addr}
rs := make([]*conn, 0, len(c.ReadDSN))
for _, rd := range c.ReadDSN {
d, err := connect(c, rd)
if err != nil {
return nil, err
}
addr = parseDSNAddr(rd)
brk := brkGroup.Get(addr)
r := &conn{DB: d, breaker: brk, conf: c, addr: addr}
rs = append(rs, r)
}
db.write = w
db.read = rs
db.master = &DB{write: db.write}
return db, nil
}
func connect(c *Config, dataSourceName string) (*sql.DB, error) {
d, err := sql.Open("mysql", dataSourceName)
if err != nil {
err = errors.WithStack(err)
return nil, err
}
d.SetMaxOpenConns(c.Active)
d.SetMaxIdleConns(c.Idle)
d.SetConnMaxLifetime(time.Duration(c.IdleTimeout))
return d, nil
}
// Begin starts a transaction. The isolation level is dependent on the driver.
func (db *DB) Begin(c context.Context) (tx *Tx, err error) {
return db.write.begin(c)
}
// Exec executes a query without returning any rows.
// The args are for any placeholder parameters in the query.
func (db *DB) Exec(c context.Context, query string, args ...interface{}) (res sql.Result, err error) {
return db.write.exec(c, query, args...)
}
// Prepare creates a prepared statement for later queries or executions.
// Multiple queries or executions may be run concurrently from the returned
// statement. The caller must call the statement's Close method when the
// statement is no longer needed.
func (db *DB) Prepare(query string) (*Stmt, error) {
return db.write.prepare(query)
}
// Prepared creates a prepared statement for later queries or executions.
// Multiple queries or executions may be run concurrently from the returned
// statement. The caller must call the statement's Close method when the
// statement is no longer needed.
func (db *DB) Prepared(query string) (stmt *Stmt) {
return db.write.prepared(query)
}
// Query executes a query that returns rows, typically a SELECT. The args are
// for any placeholder parameters in the query.
func (db *DB) Query(c context.Context, query string, args ...interface{}) (rows *Rows, err error) {
idx := db.readIndex()
for i := range db.read {
if rows, err = db.read[(idx+i)%len(db.read)].query(c, query, args...); !ecode.EqualError(ecode.ServiceUnavailable, err) {
return
}
}
return db.write.query(c, query, args...)
}
// QueryRow executes a query that is expected to return at most one row.
// QueryRow always returns a non-nil value. Errors are deferred until Row's
// Scan method is called.
func (db *DB) QueryRow(c context.Context, query string, args ...interface{}) *Row {
idx := db.readIndex()
for i := range db.read {
if row := db.read[(idx+i)%len(db.read)].queryRow(c, query, args...); !ecode.EqualError(ecode.ServiceUnavailable, row.err) {
return row
}
}
return db.write.queryRow(c, query, args...)
}
func (db *DB) readIndex() int {
if len(db.read) == 0 {
return 0
}
v := atomic.AddInt64(&db.idx, 1)
return int(v) % len(db.read)
}
// Close closes the write and read database, releasing any open resources.
func (db *DB) Close() (err error) {
if e := db.write.Close(); e != nil {
err = errors.WithStack(e)
}
for _, rd := range db.read {
if e := rd.Close(); e != nil {
err = errors.WithStack(e)
}
}
return
}
// Ping verifies a connection to the database is still alive, establishing a
// connection if necessary.
func (db *DB) Ping(c context.Context) (err error) {
if err = db.write.ping(c); err != nil {
return
}
for _, rd := range db.read {
if err = rd.ping(c); err != nil {
return
}
}
return
}
// Master return *DB instance direct use master conn
// use this *DB instance only when you have some reason need to get result without any delay.
func (db *DB) Master() *DB {
if db.master == nil {
panic(ErrNoMaster)
}
return db.master
}
func (db *conn) onBreaker(err *error) {
if err != nil && *err != nil && *err != sql.ErrNoRows && *err != sql.ErrTxDone {
db.breaker.MarkFailed()
} else {
db.breaker.MarkSuccess()
}
}
func (db *conn) begin(c context.Context) (tx *Tx, err error) {
now := time.Now()
defer slowLog("Begin", now)
t, ok := trace.FromContext(c)
if ok {
t = t.Fork(_family, "begin")
t.SetTag(trace.String(trace.TagAddress, db.addr), trace.String(trace.TagComment, ""))
defer func() {
if err != nil {
t.Finish(&err)
}
}()
}
if err = db.breaker.Allow(); err != nil {
_metricReqErr.Inc(db.addr, db.addr, "begin", "breaker")
return
}
_, c, cancel := db.conf.TranTimeout.Shrink(c)
rtx, err := db.BeginTx(c, nil)
_metricReqDur.Observe(int64(time.Since(now)/time.Millisecond), db.addr, db.addr, "begin")
if err != nil {
err = errors.WithStack(err)
cancel()
return
}
tx = &Tx{tx: rtx, t: t, db: db, c: c, cancel: cancel}
return
}
func (db *conn) exec(c context.Context, query string, args ...interface{}) (res sql.Result, err error) {
now := time.Now()
defer slowLog(fmt.Sprintf("Exec query(%s) args(%+v)", query, args), now)
if t, ok := trace.FromContext(c); ok {
t = t.Fork(_family, "exec")
t.SetTag(trace.String(trace.TagAddress, db.addr), trace.String(trace.TagComment, query))
defer t.Finish(&err)
}
if err = db.breaker.Allow(); err != nil {
_metricReqErr.Inc(db.addr, db.addr, "exec", "breaker")
return
}
_, c, cancel := db.conf.ExecTimeout.Shrink(c)
res, err = db.ExecContext(c, query, args...)
cancel()
db.onBreaker(&err)
_metricReqDur.Observe(int64(time.Since(now)/time.Millisecond), db.addr, db.addr, "exec")
if err != nil {
err = errors.Wrapf(err, "exec:%s, args:%+v", query, args)
}
return
}
func (db *conn) ping(c context.Context) (err error) {
now := time.Now()
defer slowLog("Ping", now)
if t, ok := trace.FromContext(c); ok {
t = t.Fork(_family, "ping")
t.SetTag(trace.String(trace.TagAddress, db.addr), trace.String(trace.TagComment, ""))
defer t.Finish(&err)
}
if err = db.breaker.Allow(); err != nil {
_metricReqErr.Inc(db.addr, db.addr, "ping", "breaker")
return
}
_, c, cancel := db.conf.ExecTimeout.Shrink(c)
err = db.PingContext(c)
cancel()
db.onBreaker(&err)
_metricReqDur.Observe(int64(time.Since(now)/time.Millisecond), db.addr, db.addr, "ping")
if err != nil {
err = errors.WithStack(err)
}
return
}
func (db *conn) prepare(query string) (*Stmt, error) {
defer slowLog(fmt.Sprintf("Prepare query(%s)", query), time.Now())
stmt, err := db.Prepare(query)
if err != nil {
err = errors.Wrapf(err, "prepare %s", query)
return nil, err
}
st := &Stmt{query: query, db: db}
st.stmt.Store(stmt)
return st, nil
}
func (db *conn) prepared(query string) (stmt *Stmt) {
defer slowLog(fmt.Sprintf("Prepared query(%s)", query), time.Now())
stmt = &Stmt{query: query, db: db}
s, err := db.Prepare(query)
if err == nil {
stmt.stmt.Store(s)
return
}
go func() {
for {
s, err := db.Prepare(query)
if err != nil {
time.Sleep(time.Second)
continue
}
stmt.stmt.Store(s)
return
}
}()
return
}
func (db *conn) query(c context.Context, query string, args ...interface{}) (rows *Rows, err error) {
now := time.Now()
defer slowLog(fmt.Sprintf("Query query(%s) args(%+v)", query, args), now)
if t, ok := trace.FromContext(c); ok {
t = t.Fork(_family, "query")
t.SetTag(trace.String(trace.TagAddress, db.addr), trace.String(trace.TagComment, query))
defer t.Finish(&err)
}
if err = db.breaker.Allow(); err != nil {
_metricReqErr.Inc(db.addr, db.addr, "query", "breaker")
return
}
_, c, cancel := db.conf.QueryTimeout.Shrink(c)
rs, err := db.DB.QueryContext(c, query, args...)
db.onBreaker(&err)
_metricReqDur.Observe(int64(time.Since(now)/time.Millisecond), db.addr, db.addr, "query")
if err != nil {
err = errors.Wrapf(err, "query:%s, args:%+v", query, args)
cancel()
return
}
rows = &Rows{Rows: rs, cancel: cancel}
return
}
func (db *conn) queryRow(c context.Context, query string, args ...interface{}) *Row {
now := time.Now()
defer slowLog(fmt.Sprintf("QueryRow query(%s) args(%+v)", query, args), now)
t, ok := trace.FromContext(c)
if ok {
t = t.Fork(_family, "queryrow")
t.SetTag(trace.String(trace.TagAddress, db.addr), trace.String(trace.TagComment, query))
}
if err := db.breaker.Allow(); err != nil {
_metricReqErr.Inc(db.addr, db.addr, "queryRow", "breaker")
return &Row{db: db, t: t, err: err}
}
_, c, cancel := db.conf.QueryTimeout.Shrink(c)
r := db.DB.QueryRowContext(c, query, args...)
_metricReqDur.Observe(int64(time.Since(now)/time.Millisecond), db.addr, db.addr, "queryrow")
return &Row{db: db, Row: r, query: query, args: args, t: t, cancel: cancel}
}
// Close closes the statement.
func (s *Stmt) Close() (err error) {
if s == nil {
err = ErrStmtNil
return
}
stmt, ok := s.stmt.Load().(*sql.Stmt)
if ok {
err = errors.WithStack(stmt.Close())
}
return
}
// Exec executes a prepared statement with the given arguments and returns a
// Result summarizing the effect of the statement.
func (s *Stmt) Exec(c context.Context, args ...interface{}) (res sql.Result, err error) {
if s == nil {
err = ErrStmtNil
return
}
now := time.Now()
defer slowLog(fmt.Sprintf("Exec query(%s) args(%+v)", s.query, args), now)
if s.tx {
if s.t != nil {
s.t.SetTag(trace.String(trace.TagAnnotation, s.query))
}
} else if t, ok := trace.FromContext(c); ok {
t = t.Fork(_family, "exec")
t.SetTag(trace.String(trace.TagAddress, s.db.addr), trace.String(trace.TagComment, s.query))
defer t.Finish(&err)
}
if err = s.db.breaker.Allow(); err != nil {
_metricReqErr.Inc(s.db.addr, s.db.addr, "stmt:exec", "breaker")
return
}
stmt, ok := s.stmt.Load().(*sql.Stmt)
if !ok {
err = ErrStmtNil
return
}
_, c, cancel := s.db.conf.ExecTimeout.Shrink(c)
res, err = stmt.ExecContext(c, args...)
cancel()
s.db.onBreaker(&err)
_metricReqDur.Observe(int64(time.Since(now)/time.Millisecond), s.db.addr, s.db.addr, "stmt:exec")
if err != nil {
err = errors.Wrapf(err, "exec:%s, args:%+v", s.query, args)
}
return
}
// Query executes a prepared query statement with the given arguments and
// returns the query results as a *Rows.
func (s *Stmt) Query(c context.Context, args ...interface{}) (rows *Rows, err error) {
if s == nil {
err = ErrStmtNil
return
}
now := time.Now()
defer slowLog(fmt.Sprintf("Query query(%s) args(%+v)", s.query, args), now)
if s.tx {
if s.t != nil {
s.t.SetTag(trace.String(trace.TagAnnotation, s.query))
}
} else if t, ok := trace.FromContext(c); ok {
t = t.Fork(_family, "query")
t.SetTag(trace.String(trace.TagAddress, s.db.addr), trace.String(trace.TagComment, s.query))
defer t.Finish(&err)
}
if err = s.db.breaker.Allow(); err != nil {
_metricReqErr.Inc(s.db.addr, s.db.addr, "stmt:query", "breaker")
return
}
stmt, ok := s.stmt.Load().(*sql.Stmt)
if !ok {
err = ErrStmtNil
return
}
_, c, cancel := s.db.conf.QueryTimeout.Shrink(c)
rs, err := stmt.QueryContext(c, args...)
s.db.onBreaker(&err)
_metricReqDur.Observe(int64(time.Since(now)/time.Millisecond), s.db.addr, s.db.addr, "stmt:query")
if err != nil {
err = errors.Wrapf(err, "query:%s, args:%+v", s.query, args)
cancel()
return
}
rows = &Rows{Rows: rs, cancel: cancel}
return
}
// QueryRow executes a prepared query statement with the given arguments.
// If an error occurs during the execution of the statement, that error will
// be returned by a call to Scan on the returned *Row, which is always non-nil.
// If the query selects no rows, the *Row's Scan will return ErrNoRows.
// Otherwise, the *Row's Scan scans the first selected row and discards the rest.
func (s *Stmt) QueryRow(c context.Context, args ...interface{}) (row *Row) {
now := time.Now()
defer slowLog(fmt.Sprintf("QueryRow query(%s) args(%+v)", s.query, args), now)
row = &Row{db: s.db, query: s.query, args: args}
if s == nil {
row.err = ErrStmtNil
return
}
if s.tx {
if s.t != nil {
s.t.SetTag(trace.String(trace.TagAnnotation, s.query))
}
} else if t, ok := trace.FromContext(c); ok {
t = t.Fork(_family, "queryrow")
t.SetTag(trace.String(trace.TagAddress, s.db.addr), trace.String(trace.TagComment, s.query))
row.t = t
}
if row.err = s.db.breaker.Allow(); row.err != nil {
_metricReqErr.Inc(s.db.addr, s.db.addr, "stmt:queryrow", "breaker")
return
}
stmt, ok := s.stmt.Load().(*sql.Stmt)
if !ok {
return
}
_, c, cancel := s.db.conf.QueryTimeout.Shrink(c)
row.Row = stmt.QueryRowContext(c, args...)
row.cancel = cancel
_metricReqDur.Observe(int64(time.Since(now)/time.Millisecond), s.db.addr, s.db.addr, "stmt:queryrow")
return
}
// Commit commits the transaction.
func (tx *Tx) Commit() (err error) {
err = tx.tx.Commit()
tx.cancel()
tx.db.onBreaker(&err)
if tx.t != nil {
tx.t.Finish(&err)
}
if err != nil {
err = errors.WithStack(err)
}
return
}
// Rollback aborts the transaction.
func (tx *Tx) Rollback() (err error) {
err = tx.tx.Rollback()
tx.cancel()
tx.db.onBreaker(&err)
if tx.t != nil {
tx.t.Finish(&err)
}
if err != nil {
err = errors.WithStack(err)
}
return
}
// Exec executes a query that doesn't return rows. For example: an INSERT and
// UPDATE.
func (tx *Tx) Exec(query string, args ...interface{}) (res sql.Result, err error) {
now := time.Now()
defer slowLog(fmt.Sprintf("Exec query(%s) args(%+v)", query, args), now)
if tx.t != nil {
tx.t.SetTag(trace.String(trace.TagAnnotation, fmt.Sprintf("exec %s", query)))
}
res, err = tx.tx.ExecContext(tx.c, query, args...)
_metricReqDur.Observe(int64(time.Since(now)/time.Millisecond), tx.db.addr, tx.db.addr, "tx:exec")
if err != nil {
err = errors.Wrapf(err, "exec:%s, args:%+v", query, args)
}
return
}
// Query executes a query that returns rows, typically a SELECT.
func (tx *Tx) Query(query string, args ...interface{}) (rows *Rows, err error) {
if tx.t != nil {
tx.t.SetTag(trace.String(trace.TagAnnotation, fmt.Sprintf("query %s", query)))
}
now := time.Now()
defer slowLog(fmt.Sprintf("Query query(%s) args(%+v)", query, args), now)
defer func() {
_metricReqDur.Observe(int64(time.Since(now)/time.Millisecond), tx.db.addr, tx.db.addr, "tx:query")
}()
rs, err := tx.tx.QueryContext(tx.c, query, args...)
if err == nil {
rows = &Rows{Rows: rs}
} else {
err = errors.Wrapf(err, "query:%s, args:%+v", query, args)
}
return
}
// QueryRow executes a query that is expected to return at most one row.
// QueryRow always returns a non-nil value. Errors are deferred until Row's
// Scan method is called.
func (tx *Tx) QueryRow(query string, args ...interface{}) *Row {
if tx.t != nil {
tx.t.SetTag(trace.String(trace.TagAnnotation, fmt.Sprintf("queryrow %s", query)))
}
now := time.Now()
defer slowLog(fmt.Sprintf("QueryRow query(%s) args(%+v)", query, args), now)
defer func() {
_metricReqDur.Observe(int64(time.Since(now)/time.Millisecond), tx.db.addr, tx.db.addr, "tx:queryrow")
}()
r := tx.tx.QueryRowContext(tx.c, query, args...)
return &Row{Row: r, db: tx.db, query: query, args: args}
}
// Stmt returns a transaction-specific prepared statement from an existing statement.
func (tx *Tx) Stmt(stmt *Stmt) *Stmt {
as, ok := stmt.stmt.Load().(*sql.Stmt)
if !ok {
return nil
}
ts := tx.tx.StmtContext(tx.c, as)
st := &Stmt{query: stmt.query, tx: true, t: tx.t, db: tx.db}
st.stmt.Store(ts)
return st
}
// Prepare creates a prepared statement for use within a transaction.
// The returned statement operates within the transaction and can no longer be
// used once the transaction has been committed or rolled back.
// To use an existing prepared statement on this transaction, see Tx.Stmt.
func (tx *Tx) Prepare(query string) (*Stmt, error) {
if tx.t != nil {
tx.t.SetTag(trace.String(trace.TagAnnotation, fmt.Sprintf("prepare %s", query)))
}
defer slowLog(fmt.Sprintf("Prepare query(%s)", query), time.Now())
stmt, err := tx.tx.Prepare(query)
if err != nil {
err = errors.Wrapf(err, "prepare %s", query)
return nil, err
}
st := &Stmt{query: query, tx: true, t: tx.t, db: tx.db}
st.stmt.Store(stmt)
return st, nil
}
// parseDSNAddr parse dsn name and return addr.
func parseDSNAddr(dsn string) (addr string) {
cfg, err := mysql.ParseDSN(dsn)
if err != nil {
// just ignore parseDSN error, mysql client will return error for us when connect.
return ""
}
return cfg.Addr
}
func slowLog(statement string, now time.Time) {
du := time.Since(now)
if du > _slowLogDuration {
log.Warn("%s slow log statement: %s time: %v", _family, statement, du)
}
}