vchimishuk/config

Package config implements parser for simple but powerful language used for configuration files.

NAME
    Package config implements parser for simple but powerful language used for
    configuration files.

AUTHORS
    Viacheslav Chimishuk <vchimishuk@yandex.ru>

COPYING
    This programm is released under the GNU General Public License version 3 or
    later, which is distributed in the COPYING file. You should have received
    a copy of the GNU General Public License along with this program.  If not,
    see <http://www.gnu.org/licenses/>.

DESCRIPTION
    Configuration file description language syntax is pretty simple and contains
    of sequence of properties and blocks.

    Property is a traditional key=value pair. Property definition exaples:
    string-property-name = "property-value"
    int-property-name = 100

    Block is a group of properties. Block definition exaples:
    block-name {
        prop-name = "value"
    }
    another-block-name {
        prop-name = "value"
        next-prop-name = "value"
    }

    Both, property and block can be optional, required or repeated. Client
    passes supported configuration file structure (number of properties,
    blocks, its type, etc) -- specification, to the parser. Parser checks
    input file according to the provided specification, so client can be sure
    that required properties are present, have expected type -- no futher
    validation needed on client-side.

    #-style comments are suppored too. Optional semicolon can be used at the
    end of property definition.

    Supported property types.
     * bool -- true or false boolean constant.
       bool-prop = true
       bool-prop = false
     * duration -- duration type. Same format as Go's time.ParseDuration() uses.
       See more: https://pkg.go.dev/time#ParseDuration
       duration-prop = 30s
       duration-prop = 1h
       duration-prop = 1h30m
     * int -- integer type
       int-prop = 100500
     * string -- double-quoted string type
       string-prop = "value"
       string-prop = "foo\"bar"

EXAMPLES
	spec := &Spec{
		Properties: []*PropertySpec{
			&PropertySpec{
				Type:    TypeString,
				Name:    "name",
				Repeat:  false,
				Require: true,
			},
			&PropertySpec{
				Type:    TypeInt,
				Name:    "size",
				Repeat:  false,
				Require: true,
			},
			&PropertySpec{
				Type:    TypeDuration,
				Name:    "duration",
				Repeat:  false,
				Require: false,
			},
		},
	}
	input := `
        name = "example"
        size = 1024
        duration = 1h
        `

	cfg, err := Parse(spec, input)
	if err != nil {
		fmt.Fprintf(os.Stderr, "configuration parsing failed: %s", err)
	}

	fmt.Printf("name = %s", cfg.StringOr("name", "default-name"))
	fmt.Printf("size = %d", cfg.Int("size"))
	fmt.Printf("duration = %d", cfg.Duration("duration"))