README
¶
go-defaults
Enabling stuctures with defaults values using struct tags.
Installation
The recommended way to install go-defaults
go get github.com/jc21/go-defaults
Examples
A basic example:
import (
"fmt"
"github.com/jc21/go-defaults"
"time"
)
type ExampleBasic struct {
Foo bool `default:"true"` //<-- StructTag with a default key
Bar string `default:"33"`
Qux int8
Dur time.Duration `default:"1m"`
}
func NewExampleBasic() *ExampleBasic {
example := new(ExampleBasic)
defaults.SetDefaults(example) //<-- This set the defaults values
return example
}
...
test := NewExampleBasic()
fmt.Println(test.Foo) //Prints: true
fmt.Println(test.Bar) //Prints: 33
fmt.Println(test.Qux) //Prints:
fmt.Println(test.Dur) //Prints: 1m0s
Caveats
At the moment, the way the default filler checks whether it should fill a struct field or not is by comparing the current field value with the corresponding zero value of that type. This has a subtle implication: the zero value set explicitly by you will get overriden by default value during SetDefaults() call. So if you need to set the field to container zero value, you need to set it explicitly AFTER setting the defaults.
Take the basic example in the above section and change it slightly:
example := ExampleBasic{
Bar: 0,
}
defaults.SetDefaults(example)
fmt.Println(example.Bar) //Prints: 33 instead of 0 (which is zero value for int)
example.Bar = 0 // set needed zero value AFTER applying defaults
fmt.Println(example.Bar) //Prints: 0
License
MIT, see LICENSE
Documentation
¶
Overview ¶
This library allow to define a default value to any struct, this is made thanks to struct tags.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func SetDefaults ¶
func SetDefaults(variable any)
SetDefaults Applies the default values to the struct object, the struct type must have the StructTag with name "default" and the directed value.
Usage
type ExampleBasic struct {
Foo bool `default:"true"`
Bar string `default:"33"`
Qux int8
Dur time.Duration `default:"2m3s"`
}
foo := &ExampleBasic{}
SetDefaults(foo)
Types ¶
type Filler ¶
type Filler struct {
FuncByName map[string]FillerFunc
FuncByType map[TypeHash]FillerFunc
FuncByKind map[reflect.Kind]FillerFunc
Tag string
}
Filler contains all the functions to fill any struct field with any type allowing to define function by Kind, Type of field name
func (*Filler) Fill ¶
Fill apply all the functions contained on Filler, setting all the possible values
func (*Filler) GetFieldsFromValue ¶
GetFieldsFromValue ...
func (*Filler) SetDefaultValue ¶
SetDefaultValue ...
func (*Filler) SetDefaultValues ¶
SetDefaultValues ...
type FillerFunc ¶
type FillerFunc func(field *FieldData)
Source Files