vitess.io/vitess@v0.16.2/go/mysql/collations/local.go (about)

     1  //go:build !collations_library
     2  
     3  /*
     4  Copyright 2021 The Vitess Authors.
     5  
     6  Licensed under the Apache License, Version 2.0 (the "License");
     7  you may not use this file except in compliance with the License.
     8  You may obtain a copy of the License at
     9  
    10      http://www.apache.org/licenses/LICENSE-2.0
    11  
    12  Unless required by applicable law or agreed to in writing, software
    13  distributed under the License is distributed on an "AS IS" BASIS,
    14  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    15  See the License for the specific language governing permissions and
    16  limitations under the License.
    17  */
    18  
    19  package collations
    20  
    21  import (
    22  	"sync"
    23  
    24  	"vitess.io/vitess/go/internal/flag"
    25  	"vitess.io/vitess/go/vt/servenv"
    26  )
    27  
    28  var defaultEnv *Environment
    29  var defaultEnvInit sync.Once
    30  
    31  // Local is the default collation Environment for Vitess. This depends
    32  // on the value of the `mysql_server_version` flag passed to this Vitess process.
    33  func Local() *Environment {
    34  	defaultEnvInit.Do(func() {
    35  		if !flag.Parsed() {
    36  			panic("collations.Local() called too early")
    37  		}
    38  		defaultEnv = NewEnvironment(servenv.MySQLServerVersion())
    39  	})
    40  	return defaultEnv
    41  }
    42  
    43  // Default returns the default collation for this Vitess process.
    44  // This is based on the local collation environment, which is based on the user's configured
    45  // MySQL version for this Vitess deployment.
    46  func Default() ID {
    47  	return ID(Local().DefaultConnectionCharset())
    48  }