78 lines
2.0 KiB
Go
78 lines
2.0 KiB
Go
package config
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import (
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"strconv"
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"strings"
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)
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// An Environment adds additional behavior to a Fetcher, such a type conversion,
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// and default values.
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//
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// `Environment`s are the primary way to communicate with various configuration
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// sources, such as the OS environment variables, the `.gitconfig`, and even
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// `map[string]string`s.
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type Environment struct {
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// Fetcher is the `Environment`'s source of data.
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Fetcher Fetcher
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}
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// EnvironmentOf creates a new `*Environment` initialized with the givne
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// `Fetcher`, "f".
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func EnvironmentOf(f Fetcher) *Environment {
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return &Environment{f}
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}
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// Get is shorthand for calling `e.Fetcher.Get(key)`.
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func (e *Environment) Get(key string) (val string, ok bool) {
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return e.Fetcher.Get(key)
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}
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// Bool returns the boolean state associated with a given key, or the value
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// "def", if no value was associated.
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//
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// The "boolean state associated with a given key" is defined as the
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// case-insensitive string comparison with the following:
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//
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// 1) true if...
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// "true", "1", "on", "yes", or "t"
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// 2) false if...
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// "false", "0", "off", "no", "f", or otherwise.
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func (e *Environment) Bool(key string, def bool) (val bool) {
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s, _ := e.Fetcher.Get(key)
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if len(s) == 0 {
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return def
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}
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switch strings.ToLower(s) {
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case "true", "1", "on", "yes", "t":
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return true
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case "false", "0", "off", "no", "f":
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return false
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default:
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return false
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}
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}
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// Int returns the int value associated with a given key, or the value "def",
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// if no value was associated.
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//
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// To convert from a the string value attached to a given key,
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// `strconv.Atoi(val)` is called. If `Atoi` returned a non-nil error, then the
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// value "def" will be returned instead.
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//
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// Otherwise, if the value was converted `string -> int` successfully, then it
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// will be returned wholesale.
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func (e *Environment) Int(key string, def int) (val int) {
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s, _ := e.Fetcher.Get(key)
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if len(s) == 0 {
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return def
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}
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i, err := strconv.Atoi(s)
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if err != nil {
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return def
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}
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return i
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}
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