config

README

Darvaza Config

darvaza.org/x/config provides helpers for dealing with config files.

AppDir

appdir contains helpers to determine the location of application specific files.

Default values

Wrappers for github.com/amery/defaults:

• SetDefaults()
• Set()
• CanUpdate()

Environment

Expand shell-style variables:

• FromString()
• FromBytes()
• FromReader()
• FromFile()

Loader

Attempts to decode an object from one of a list of filenames.

Validations

Wrappers for github.com/go-playground/validator/v10:

• Validate()
• AsValidationError()
• and Prepare(). calling SetDefaults() and Validate().

See also

• JPI Technologies' Open Source Software
• darvaza libraries
  • darvaza.org/core
  • darvaza.org/x
• darvaza servers
  • darvaza.org/penne
  • darvaza.org/sidecar
• third party libraries
  • github.com/amery/defaults
  • github.com/go-playground/validator
  • mvdan.cc/sh

Documentation

Overview

Package config provides helpers for handling config structs

Index

• func AsValidationErrors(err error) (validator.ValidationErrors, bool)
• func CanUpdate(v any) bool
• func Join(directories []string, base string, extensions []string) ([]string, error)
• func NewPathError(filename, op string, err error) *os.PathError
• func Prepare(v any) error
• func Set(v any) error
• func SetDefaults(v any) error
• func Validate(v any) error
• type Decoder
• type DecoderFunc
  • func (df DecoderFunc[T]) Decode(name string, data []byte) (*T, error)
• type Loader
  • func (l *Loader[T]) Last() (fs.FS, string)
  • func (l *Loader[T]) New() (*T, error)
  • func (l *Loader[T]) NewFromFile(fSys fs.FS, names ...string) (*T, error)
  • func (l *Loader[T]) NewFromFileOS(names ...string) (*T, error)
• type Option

Functions

func AsValidationErrors

func AsValidationErrors(err error) (validator.ValidationErrors, bool)

AsValidationErrors gives access to a slice of validator.FieldError

func CanUpdate

func CanUpdate(v any) bool

CanUpdate returns true when the given value is an initial value of its type

func Join

func Join(directories []string, base string, extensions []string) ([]string, error)

Join combines a list of directories with a name and an optional list of extensions. This are `/` separated, absolute, but without the initial `/`. Following fs.ValidPath rules. Final result is cleaned.

func NewPathError

func NewPathError(filename, op string, err error) *os.PathError

NewPathError is a shortcut to generate os.PathError.

func Prepare

func Prepare(v any) error

Prepare runs SetDefaults and Validate

func Set

func Set(v any) error

Set applies `default` struct-tags and SetDefaults() recursively. If the given object has a `SetDefaults() error` method, it will be ignored. Any `SetDefaults() error` deeper in the struct will be called.

func SetDefaults

func SetDefaults(v any) error

SetDefaults applies `default` struct-tags and SetDefaults() recursively. If the given object has a `SetDefaults() error` method, it will be invoked instead.

func Validate

func Validate(v any) error

Validate validates exposed fields including nested structs

Types

type Decoder

type Decoder[T any] interface {
	Decode(name string, data []byte) (*T, error)
}

A Decoder attempts to convert the contents of a file into a [T] type.

type DecoderFunc

type DecoderFunc[T any] func(string, []byte) (*T, error)

A DecoderFunc represents a function that can act as a full Decoder.

func (DecoderFunc[T]) Decode

func (df DecoderFunc[T]) Decode(name string, data []byte) (*T, error)

Decode converts the contents of a file into an entity of a given [T] type.

type Loader

type Loader[T any] struct {

	// NewDecoder returns a [Decoder] based on the filename
	NewDecoder func(string) (Decoder[T], error)

	// IsSkip checks if the error returned by the [Decoder]
	// indicates we should try the next option instead of
	// failing. [os.IsNotExist] is always tested first.
	IsSkip func(error) bool

	// Options are applied to objects after decoding and
	// before Load() returns.
	Options []Option[T]
	// contains filtered or unexported fields
}

Loader tries to load an object from the first success on a list of options.

func (*Loader[T]) Last

func (l *Loader[T]) Last() (fs.FS, string)

Last returns the filename last used. empty if it was the Fallback.

func (*Loader[T]) New

func (l *Loader[T]) New() (*T, error)

New creates a new object

func (*Loader[T]) NewFromFile

func (l *Loader[T]) NewFromFile(fSys fs.FS, names ...string) (*T, error)

NewFromFile returns the first successfully decoded option.

func (*Loader[T]) NewFromFileOS

func (l *Loader[T]) NewFromFileOS(names ...string) (*T, error)

NewFromFileOS returns the first successfully decoded option.

type Option

type Option[T any] func(*T) error

An Option if a function used to configure an object after decoding.