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