README
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go-optional
A Cascading option resolver designed for numerious sources of configuration information
Documentation
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Overview ¶
Package optional provides a cascading option resolver for cli applications
Usage: Create a resolver by calling New(&config). Config should be a struct Add sources by calling AddSource.
Example ¶
type Config struct {
ConfigPath string `default:"/etc/test/config.json" arg:"c" arg:"conf-path"`
Name string `arg:"n" arg:"name" default:"New User"`
Goodbye bool `default:"false" arg:"b" arg:"!h" arg:"goodbye"`
}
config := Config{}
opts := New(&config)
opts.AddSourceFast(0, opts.StructTags("default")) // Fast because we dont read until another AddSource
opts.AddSource(2, opts.Arguments(
[]string{"optional_test", "-n", "Jamie", "--conf-path", "c:/test.conf"},
)) //normaly opts.AddSource(opts.Arguments(os.Args))
c, err := ioutil.ReadFile(config.ConfigPath) //Open JSON on disk
if err != nil {
fmt.Println(err.Error())
} else {
m := make(map[string]interface{})
json.Unmarshal(c, &m)
opts.AddSource(1, Wrapped{m})
}
//Config should be set as:
// ConfigPath: "D:/test.conf" (from Arguments)
// Name: "Jamie" (from Arguments)
// Goodbye: false (from Defaults)
h := "Hello "
if config.Goodbye {
h = "Goodbye "
}
fmt.Println(h + config.Name)
fmt.Println(config.ConfigPath)
//Output will be: Hello Jamie (Unless you changed the conf)
Output:
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type ArgumentsOptionSource ¶
type ArgumentsOptionSource struct {
// contains filtered or unexported fields
}
ArgumentsOptionSource implements OptionSource, pulling data from the passed argument array
func (ArgumentsOptionSource) Get ¶
func (s ArgumentsOptionSource) Get(key string) (interface{}, bool)
Get implements OptionSource
type OptionSource ¶
type OptionSource interface {
//Get will be given a path, period deliminated and should return the value related to it
Get(key string) (value interface{}, ok bool)
}
A OptionSource can be passed to AddSource to add a source for values
type Opts ¶
type Opts struct {
// contains filtered or unexported fields
}
Opts holds cascaded sources
func (*Opts) AddSource ¶
func (o *Opts) AddSource(i int, s OptionSource)
AddSource adds a source to the opt, 'i' being the priority level (higher number = higher priority)
func (*Opts) AddSourceFast ¶
func (o *Opts) AddSourceFast(i int, s OptionSource)
AddSourceFast adds a source to the opt without updating the parent struct
Example ¶
type Config struct {
A string `default:"default"`
B string `default:"default" someOtherDefault:"OtherDefault"`
C string `default:"default"`
}
config := Config{
A: "Allocate", // Will be overwritten
}
opts := New(&config) // Does not change struct
fmt.Println(config)
//{Allocate }
opts.AddSource(1, opts.StructTags("default"))
opts.AddSourceFast(2, opts.StructTags("someOtherDefault"))
fmt.Println(config)
//{default default default}
opts.Recalc()
fmt.Println(config)
//{default OtherDefault default}
Output: {Allocate } {default default default} {default OtherDefault default}
func (*Opts) Arguments ¶
func (o *Opts) Arguments(s []string) ArgumentsOptionSource
Arguments creates a (Arguments)OptionSource pulling data from the passed argument array.
Parser rules shorthand (1 char) has a single dash longhand (1+char ) has two dashes shorthand bools can be strung together -abcd will set a,b,c, and d to true shorthand bools with names begining with a '!' will be inverted ie: Fast bool `args:"Fast" args:"f" args:"!s"` '--' stops parsing
func (*Opts) Recalc ¶
func (o *Opts) Recalc()
Recalc sets all of the values in the struct to the correct values This is called automatically after AddSource
func (*Opts) StructTags ¶
func (o *Opts) StructTags(key string) StructTagsOptionSource
StructTags creates a (StructTags)OptionSource pulling from struct's tags
type StructTagsOptionSource ¶
type StructTagsOptionSource struct {
// contains filtered or unexported fields
}
StructTagsOptionSource implements OptionSource, pulling data from Struct tags
func (StructTagsOptionSource) Get ¶
func (s StructTagsOptionSource) Get(key string) (interface{}, bool)
Get implements OptionSource
Source Files