Golang Session.Run方法代碼示例

// CurrentStatus returns the status of the replica set for the given session.
func CurrentStatus(session *mgo.Session) (*Status, error) {
	status := &Status{}
	err := session.Run("replSetGetStatus", status)
	if err != nil {
		return nil, fmt.Errorf("cannot get replica set status: %v", err)
	}
	return status, nil
}

// IsMaster returns information about the configuration of the node that
// the given session is connected to.
func IsMaster(session *mgo.Session) (*IsMasterResults, error) {
	results := &IsMasterResults{}
	err := session.Run("isMaster", results)
	if err != nil {
		return nil, err
	}
	return results, nil
}

// Optime returns the Timestamp for mongo getoptime command, session should be a direct session.
func Optime(s *mgo.Session) (*Timestamp, error) {
	ts := new(Timestamp)

	stats := struct {
		Optime optime
	}{}

	if err := s.Run("getoptime", &stats); err != nil {
		return ts, err
	}

	*ts = Timestamp(stats.Optime)
	return ts, nil
}

// applyRelSetConfig applies the new config to the mongo session. It also logs
// what the changes are. It checks if the replica set changes cause the DB
// connection to be dropped. If so, it Refreshes the session and tries to Ping
// again.
func applyRelSetConfig(cmd string, session *mgo.Session, oldconfig, newconfig *Config) error {
	logger.Debugf("%s() changing replica set\nfrom %s\n  to %s",
		cmd, fmtConfigForLog(oldconfig), fmtConfigForLog(newconfig))
	err := session.Run(bson.D{{"replSetReconfig", newconfig}}, nil)
	// We will only try to Ping 2 times
	for i := 0; i < 2; i++ {
		if err == io.EOF {
			// If the primary changes due to replSetReconfig, then all
			// current connections are dropped.
			// Refreshing should fix us up.
			logger.Debugf("got EOF while running %s(), calling session.Refresh()", cmd)
			session.Refresh()
		} else if err != nil {
			// For all errors that aren't EOF, return immediately
			return err
		}
		// err is either nil or EOF and we called Refresh, so Ping to
		// make sure we're actually connected
		err = session.Ping()
		// Change the command because it is the new command we ran
		cmd = "Ping"
	}
	return err
}