x

README

Utility library for Go

go.zoe.im/x

Don't repeat yourself, every piece of knowledge must have a single, unambiguous, authoritative representation within a system.

Documentation

Index

• Variables
• func Bytes2Str(data []byte) string
• func GraceRun(f func() error) error
• func GraceStart(f func(ch GraceSignalChan) error) error
• func HomeDir() (string, error)
• func IsInContainer(pid int) (bool, error)
• func LineWriter(fn func(line []byte) error, ignoreEmpty bool) io.Writer
• func Reset()
• func Str2Bytes(str string) []byte
• func WithHomeDir(path string) (string, error)
• type Duration
  • func (d Duration) MarshalJSON() ([]byte, error)
  • func (d *Duration) UnmarshalJSON(b []byte) error
• type Errors
  • func NewErrors(errs ...error) Errors
  • func (es Errors) Add(ex ...error)
  • func (es Errors) Error() string
  • func (es Errors) IsNil() bool
• type GraceSignalChan
• type UUID
  • func MustUUID(uuid UUID, err error) UUID
  • func NewRandomUUID() (UUID, error)
  • func NewRandomUUIDFromReader(r io.Reader) (UUID, error)
  • func NewUUID() UUID
  • func ParseUUID(s string) (UUID, error)
  • func (uuid UUID) String() string
  • func (uuid UUID) URN() string
• type Value
  • func NewValue[T comparable](v T) *Value[T]
  • func Unwrap[T comparable](mv T, err error) *Value[T]
  • func (v *Value[T]) Or(r T) *Value[T]
  • func (v *Value[T]) Unwrap(mv T, err error) *Value[T]
  • func (v *Value[T]) Value() T

Examples

• Bytes2Str
• NewRandomUUID
• NewUUID
• Str2Bytes

Variables

var DisableCache bool

DisableCache will disable caching of the home directory. Caching is enabled by default.

Functions

func Bytes2Str

func Bytes2Str(data []byte) string

Bytes2Str converts byte slice to a string without memory allocation. See https://groups.google.com/forum/#!msg/Golang-Nuts/ENgbUzYvCuU/90yGx7GUAgAJ .

Note it may break if string and/or slice header will change in the future go versions.

Example

func GraceRun

func GraceRun(f func() error) error

GraceRun grace run a function

func GraceStart

func GraceStart(f func(ch GraceSignalChan) error) error

GraceStart start a grace function

func HomeDir

func HomeDir() (string, error)

HomeDir returns the home directory for the executing user.

This uses an OS-specific method for discovering the home directory. An error is returned if a home directory cannot be detected.

func IsInContainer

func IsInContainer(pid int) (bool, error)

IsInContainer checks if the service is being executed in docker or lxc container.

func LineWriter

func LineWriter(fn func(line []byte) error, ignoreEmpty bool) io.Writer

LineWriter return a writer with a line callback

func Reset

func Reset()

Reset clears the cache, forcing the next call to Dir to re-detect the home directory. This generally never has to be called, but can be useful in tests if you're modifying the home directory via the HOME env var or something.

func Str2Bytes

func Str2Bytes(str string) []byte

Str2Bytes converts string to a byte slice without memory allocation.

Note it may break if string and/or slice header will change in the future go versions.

Example

func WithHomeDir

func WithHomeDir(path string) (string, error)

WithHomeDir expands the path to include the home directory if the path is prefixed with `~`. If it isn't prefixed with `~`, the path is returned as-is.

Types

type Duration

type Duration time.Duration

Duration implement JSON marshall for time.Duration

func (Duration) MarshalJSON

func (d Duration) MarshalJSON() ([]byte, error)

MarshalJSON implement MarshalJSON

func (*Duration) UnmarshalJSON

func (d *Duration) UnmarshalJSON(b []byte) error

UnmarshalJSON implement UnmarshalJSON

type Errors

type Errors []error

Errors contains multi error

func NewErrors

func NewErrors(errs ...error) Errors

NewErrors create errors

func (Errors) Add

func (es Errors) Add(ex ...error)

Add ad a new error to errors

func (Errors) Error

func (es Errors) Error() string

Error implements the error interface

func (Errors) IsNil

func (es Errors) IsNil() bool

IsNil return if contains no error

type GraceSignalChan

type GraceSignalChan chan struct{}

GraceSignalChan grace signal chan

type UUID

type UUID [16]byte

A UUID is a 128 bit (16 byte) Universal Unique IDentifier as defined in RFC 4122.

var (
	Nil UUID // empty UUID, all zeros
)

Well known namespace IDs and UUIDs

func MustUUID

func MustUUID(uuid UUID, err error) UUID

MustUUID returns uuid if err is nil and panics otherwise.

func NewRandomUUID

func NewRandomUUID() (UUID, error)

NewRandomUUID returns a Random (Version 4) UUID.

The strength of the UUIDs is based on the strength of the crypto/rand package.

A note about uniqueness derived from the UUID Wikipedia entry:

Randomly generated UUIDs have 122 random bits.  One's annual risk of being
hit by a meteorite is estimated to be one chance in 17 billion, that
means the probability is about 0.00000000006 (6 × 10−11),
equivalent to the odds of creating a few tens of trillions of UUIDs in a
year and having one duplicate.

Example

func NewRandomUUIDFromReader

func NewRandomUUIDFromReader(r io.Reader) (UUID, error)

NewRandomUUIDFromReader returns a Random (Version 4) UUID.

func NewUUID

func NewUUID() UUID

NewUUID creates a new random UUID or panics. New is equivalent to the expression

uuid.Must(uuid.NewRandom())

Example

func ParseUUID

func ParseUUID(s string) (UUID, error)

ParseUUID decodes s into a UUID or returns an error. Both the standard UUID forms of xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx and urn:uuid:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx are decoded as well as the Microsoft encoding {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx} and the raw hex encoding: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.

func (UUID) String

func (uuid UUID) String() string

String returns the string form of uuid, xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx , or "" if uuid is invalid.

func (UUID) URN

func (uuid UUID) URN() string

URN returns the RFC 2141 URN form of uuid, urn:uuid:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx, or "" if uuid is invalid.

type Value

type Value[T comparable] struct {
	// contains filtered or unexported fields
}

func NewValue

func NewValue[T comparable](v T) *Value[T]

NewValue create the value for expression

func Unwrap

func Unwrap[T comparable](mv T, err error) *Value[T]

Unwrap the value from (value, error) if err != nil, return v

func (*Value[T]) Or

func (v *Value[T]) Or(r T) *Value[T]

Or Value(a).Or(-1)

func (*Value[T]) Unwrap

func (v *Value[T]) Unwrap(mv T, err error) *Value[T]

Unwrap the value from (value, error) if err != nil, return v

func (*Value[T]) Value

func (v *Value[T]) Value() T