config2go

automatically convert yaml, json, toml etc. file into go file with struct.

how to install

go install github.com/xylonx/config2go@latest

How to use

config2go -s ${sourceConfig} -t ${targetConfig} -p ${package} -t ${tags}

for more information, run config2go -h.

how to deploy your own parser

the flow can be divided into 3 main parts:

1. parser: input anything you want, and output the Node tree

type Node struct {
	// inner node properties
	// the tag key of the node
	TagKey string
	// the struct field name
	FieldName string
	// the node type: string, bool, int64, float64, Slice, Map and so on
	Type reflect.Kind

	// sort with alphabeta
	Child []Node
}

type Parser interface {
	ParseToNodeTree() (*Node, error)
}

the Tag key is used to generate tags while the field key is used to generate the struct Field with UpperCamel.

don't worry about it, config2go will convert camel case, snake case and kebab case into UpperCamel case😃

2. define how tag works

type TagFunc func(tagKey string) (tags string)

it receive the tagKey define in Node below, and output the whole tags (include ` symbol).

I provider 2 embedded tagFunc:

• AppendAllFields

// defined in converter package
var AppendAllFields = func(tags []string) TagFunc

// use
converter.NewConverter(parser, converter.AppendAllFields([]string{"json", "yaml"}))

it add tags for all expose struct field.

the output is like below:

Name string `json:"name" yaml:"name" `

• noopTagFunc

converter.NewConverter(parser, converter.noopTagFunc)

it add no tags for struct field.

the output is like below:

Name string ``

3. new Converter and Convert

converter := converter.NewConverter(parser, <TagFunc>)
converter.Convert(<targetPackage>, <targetFile>)

now, the generated source code will write into <targetFile>

example

• yaml

application:
  host: 0.0.0.0
  port: 8080
  read_timeout: 5
  write_timeout: 5

users:
  - username: Alice
    password: p@ssw0rd
  - username: Bob
    password: P@ssw0rd

ids:
  - A
  - B
  - C

• source code

/*
	Code generated by config2go(https://github.com/xylonx/config2go)
	DON EDIT!
*/
package config

type Setting struct {
	Application struct {
		Host         string `mapstructure:"host" json:"host" yaml:"host" `
		Port         int64  `mapstructure:"port" json:"port" yaml:"port" `
		ReadTimeout  int64  `mapstructure:"read_timeout" json:"read_timeout" yaml:"read_timeout" `
		WriteTimeout int64  `mapstructure:"write_timeout" json:"write_timeout" yaml:"write_timeout" `
	} `mapstructure:"application" json:"application" yaml:"application" `
	Ids   []string `mapstructure:"ids" json:"ids" yaml:"ids" `
	Users []struct {
		Password string `mapstructure:"password" json:"password" yaml:"password" `
		Username string `mapstructure:"username" json:"username" yaml:"username" `
	} `mapstructure:"users" json:"users" yaml:"users" `
}