github.com/distributedio/configo

Configo

Configo is a go library to parse toml configuration using struct tags

Features

• Configuring parser behaviour using struct tags
• Setting default value or as required
• Validating value using regex, range expression or named validator
• Generating toml template with human friendly information based on go struct and tags
• Building conf file generation tools using configo-build

QuickStart

• Install configo-build tool for config generation

go get github.com/distributedio/configo/bin/configo-build

• Define a struct in package conf

package conf

type Config struct {
        Listen  string `cfg:"listen; :8804; netaddr; The address the server to listen"`
        MaxConn int    `cfg:"max-connection; 10000; numeric; Max number of concurrent connections"`
        Redis   struct {
                Cluster []string `cfg:"cluster; required; dialstring; The addresses of redis cluster"`
        }
}

• Use configo-build tool generate config builder, if everything goes well, you'll get a binary called conf.Config.cfg

configo-build ./conf.Config

or use the absolute path

configo-build github.com/distributedio/configo/example/conf.Config

• execute builer to generate a toml

conf.config.cfg > conf.toml

or patch you toml file if it is already existed

conf.config.cfg -patch conf.toml

• Use your config in your code

import "github.com/distributedio/configo"

var conf conf.Config

if err := configo.Parse("{PATH_TO_YOUR_TOML}", &conf) ;err != nil {
// handle the error
}

Toml

shafreeck/toml is a modification version of naoina/toml, adding the abililty to parse complex struct tags and with bugs fixed.

Validation

configo has a builtin validator with regex and range support

Supported named validator

• netaddr
• url
• nonempty
• dialstring
• boolean
• numeric
• printableascii
• path

and you can also use compare operator and regExp in tags

> 1 //greater than 1
>=1 //greater than or equal to 1
>1 <10 //greater than 1 and less than 10, space indicates the "and" of rules

(1, ) //range expression, same as >1
(1, 10) // >1 <10
(1,10]  // >1 <=10

/[0-9]/ //regex matching

/[0-9]+/ (1, 10) // the value should satisfy both the regex and range expression

netaddr //named validator, used to validate a network address
numeric  >10 ( ,100)// mix different expressions, 'and' is used to combine all expressions

See the Suppoted Vaildator for all valid "named validators"

Struct tags

tags has a key 'cfg' and its value consists of four parts: "name; default value or required; rule; descripion". All four parts are splited by ";".

For example:

Listen `cfg:"listen; :8804; netaddr; The listen address of server"`

It looks like this when being marshaled to toml

#type:        string
#rules:       netaddr
#description: The listen address of server
#default:     :8804
#listen=":8804"

You can see that we have rich information about the option. And the option is commented out too because it has a default value.

configo-build

Configo comes with a util tool called configo-build to build a configration file generator for you.

You can use the generator to generate your toml file or update it when you changed your source code(the configuration struct).

configo-build ./conf.Config
#build a conf generator, the format of arg is "package.struct" package can be
#absolute or relative(golang takes it as an absolute package if it is without
#the prefix "./" or "../").

#the built program has a name with format:<package>.<struct>.cfg, for example
#"conf.config.cfg"

Generating your configuration file with the built generator

conf.config.cfg > conf.toml #generating
conf.config.cfg -patch conf.toml #updating if conf.toml has already existed