service/vendor/go.mongodb.org/mongo-driver/mongo/readpref/mode.go

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2023-12-21 22:17:40 +08:00
// Copyright (C) MongoDB, Inc. 2017-present.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
package readpref
import (
"fmt"
"strings"
)
// Mode indicates the user's preference on reads.
type Mode uint8
// Mode constants
const (
_ Mode = iota
// PrimaryMode indicates that only a primary is
// considered for reading. This is the default
// mode.
PrimaryMode
// PrimaryPreferredMode indicates that if a primary
// is available, use it; otherwise, eligible
// secondaries will be considered.
PrimaryPreferredMode
// SecondaryMode indicates that only secondaries
// should be considered.
SecondaryMode
// SecondaryPreferredMode indicates that only secondaries
// should be considered when one is available. If none
// are available, then a primary will be considered.
SecondaryPreferredMode
// NearestMode indicates that all primaries and secondaries
// will be considered.
NearestMode
)
// ModeFromString returns a mode corresponding to
// mode.
func ModeFromString(mode string) (Mode, error) {
switch strings.ToLower(mode) {
case "primary":
return PrimaryMode, nil
case "primarypreferred":
return PrimaryPreferredMode, nil
case "secondary":
return SecondaryMode, nil
case "secondarypreferred":
return SecondaryPreferredMode, nil
case "nearest":
return NearestMode, nil
}
return Mode(0), fmt.Errorf("unknown read preference %v", mode)
}
// String returns the string representation of mode.
func (mode Mode) String() string {
switch mode {
case PrimaryMode:
return "primary"
case PrimaryPreferredMode:
return "primaryPreferred"
case SecondaryMode:
return "secondary"
case SecondaryPreferredMode:
return "secondaryPreferred"
case NearestMode:
return "nearest"
default:
return "unknown"
}
}
// IsValid checks whether the mode is valid.
func (mode Mode) IsValid() bool {
switch mode {
case PrimaryMode,
PrimaryPreferredMode,
SecondaryMode,
SecondaryPreferredMode,
NearestMode:
return true
default:
return false
}
}