vitess.io/vitess@v0.16.2/go/vt/vtorc/inst/instance_topology_dao.go (about) 1 /* 2 Copyright 2015 Shlomi Noach, courtesy Booking.com 3 4 Licensed under the Apache License, Version 2.0 (the "License"); 5 you may not use this file except in compliance with the License. 6 You may obtain a copy of the License at 7 8 http://www.apache.org/licenses/LICENSE-2.0 9 10 Unless required by applicable law or agreed to in writing, software 11 distributed under the License is distributed on an "AS IS" BASIS, 12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 See the License for the specific language governing permissions and 14 limitations under the License. 15 */ 16 17 package inst 18 19 // Max concurrency for bulk topology operations 20 const topologyConcurrency = 128 21 22 var topologyConcurrencyChan = make(chan bool, topologyConcurrency) 23 24 // ExecuteOnTopology will execute given function while maintaining concurrency limit 25 // on topology servers. It is safe in the sense that we will not leak tokens. 26 func ExecuteOnTopology(f func()) { 27 topologyConcurrencyChan <- true 28 defer func() { _ = recover(); <-topologyConcurrencyChan }() 29 f() 30 }