uuid

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Published: Dec 17, 2024 License: Apache-2.0, MIT Imports: 15 Imported by: 0

Documentation

Overview

Package uuid provides implementations of the Universally Unique Identifier (UUID), as specified in RFC-4122 and DCE 1.1.

RFC-4122[1] provides the specification for versions 1, 3, 4, and 5.

DCE 1.1[2] provides the specification for version 2.

[1] https://tools.ietf.org/html/rfc4122 [2] http://pubs.opengroup.org/onlinepubs/9696989899/chap5.htm#tagcjh_08_02_01_01

Index

Constants

View Source
const (
	V1 byte // Version 1 (date-time and MAC address)
	V2      // Version 2 (date-time and MAC address, DCE security version)
	V3      // Version 3 (namespace name-based)
	V4      // Version 4 (random)
	V5      // Version 5 (namespace name-based)
)

UUID versions.

View Source
const (
	VariantNCS byte = iota
	VariantRFC4122
	VariantMicrosoft
	VariantFuture
)

UUID layout variants.

View Source
const (
	DomainPerson = iota
	DomainGroup
	DomainOrg
)

UUID DCE domains.

View Source
const Size = 16

Size of a UUID in bytes.

Variables

View Source
var (
	NamespaceDNS  = Must(FromString("6ba7b810-9dad-11d1-80b4-00c04fd430c8"))
	NamespaceURL  = Must(FromString("6ba7b811-9dad-11d1-80b4-00c04fd430c8"))
	NamespaceOID  = Must(FromString("6ba7b812-9dad-11d1-80b4-00c04fd430c8"))
	NamespaceX500 = Must(FromString("6ba7b814-9dad-11d1-80b4-00c04fd430c8"))
)

Predefined namespace UUIDs.

View Source
var Nil = UUID{}

Nil is the nil UUID, as specified in RFC-4122, that has all 128 bits set to zero.

Functions

func Fuzz

func Fuzz(data []byte) int

Fuzz implements a simple fuzz test for FromString / UnmarshalText.

To run:

$ go get github.com/dvyukov/go-fuzz/...
$ cd $GOPATH/src/k8s.io/autoscaler/cluster-autoscaler/cloudprovider/exoscale/internal/uuid
$ go-fuzz-build k8s.io/autoscaler/cluster-autoscaler/cloudprovider/exoscale/internal/uuid
$ go-fuzz -bin=uuid-fuzz.zip -workdir=./testdata

If you make significant changes to FromString / UnmarshalText and add new cases to fromStringTests (in codec_test.go), please run

$ go test -seed_fuzz_corpus

to seed the corpus with the new interesting inputs, then run the fuzzer.

Types

type Gen

type Gen struct {
	// contains filtered or unexported fields
}

Gen is a reference UUID generator based on the specifications laid out in RFC-4122 and DCE 1.1: Authentication and Security Services. This type satisfies the Generator interface as defined in this package.

For consumers who are generating V1 UUIDs, but don't want to expose the MAC address of the node generating the UUIDs, the NewGenWithHWAF() function has been provided as a convenience. See the function's documentation for more info.

The authors of this package do not feel that the majority of users will need to obfuscate their MAC address, and so we recommend using NewGen() to create a new generator.

func NewGen

func NewGen() *Gen

NewGen returns a new instance of Gen with some default values set. Most people should use this.

func NewGenWithHWAF

func NewGenWithHWAF(hwaf HWAddrFunc) *Gen

NewGenWithHWAF builds a new UUID generator with the HWAddrFunc provided. Most consumers should use NewGen() instead.

This is used so that consumers can generate their own MAC addresses, for use in the generated UUIDs, if there is some concern about exposing the physical address of the machine generating the UUID.

The Gen generator will only invoke the HWAddrFunc once, and cache that MAC address for all the future UUIDs generated by it. If you'd like to switch the MAC address being used, you'll need to create a new generator using this function.

func (*Gen) NewV1

func (g *Gen) NewV1() (UUID, error)

NewV1 returns a UUID based on the current timestamp and MAC address.

func (*Gen) NewV2

func (g *Gen) NewV2(domain byte) (UUID, error)

NewV2 returns a DCE Security UUID based on the POSIX UID/GID.

func (*Gen) NewV3

func (g *Gen) NewV3(ns UUID, name string) UUID

NewV3 returns a UUID based on the MD5 hash of the namespace UUID and name.

func (*Gen) NewV4

func (g *Gen) NewV4() (UUID, error)

NewV4 returns a randomly generated UUID.

func (*Gen) NewV5

func (g *Gen) NewV5(ns UUID, name string) UUID

NewV5 returns a UUID based on SHA-1 hash of the namespace UUID and name.

type Generator

type Generator interface {
	NewV1() (UUID, error)
	NewV2(domain byte) (UUID, error)
	NewV3(ns UUID, name string) UUID
	NewV4() (UUID, error)
	NewV5(ns UUID, name string) UUID
}

Generator provides an interface for generating UUIDs.

var DefaultGenerator Generator = NewGen()

DefaultGenerator is the default UUID Generator used by this package.

type HWAddrFunc

type HWAddrFunc func() (net.HardwareAddr, error)

HWAddrFunc is the function type used to provide hardware (MAC) addresses.

type NullUUID

type NullUUID struct {
	UUID  UUID
	Valid bool
}

NullUUID can be used with the standard sql package to represent a UUID value that can be NULL in the database.

func (NullUUID) MarshalJSON

func (u NullUUID) MarshalJSON() ([]byte, error)

MarshalJSON marshals the NullUUID as null or the nested UUID

func (*NullUUID) Scan

func (u *NullUUID) Scan(src interface{}) error

Scan implements the sql.Scanner interface.

func (*NullUUID) UnmarshalJSON

func (u *NullUUID) UnmarshalJSON(b []byte) error

UnmarshalJSON unmarshals a NullUUID

func (NullUUID) Value

func (u NullUUID) Value() (driver.Value, error)

Value implements the driver.Valuer interface.

type Timestamp

type Timestamp uint64

Timestamp is the count of 100-nanosecond intervals since 00:00:00.00, 15 October 1582 within a V1 UUID. This type has no meaning for V2-V5 UUIDs since they don't have an embedded timestamp.

func TimestampFromV1

func TimestampFromV1(u UUID) (Timestamp, error)

TimestampFromV1 returns the Timestamp embedded within a V1 UUID. Returns an error if the UUID is any version other than 1.

func (Timestamp) Time

func (t Timestamp) Time() (time.Time, error)

Time returns the UTC time.Time representation of a Timestamp

type UUID

type UUID [Size]byte

UUID is an array type to represent the value of a UUID, as defined in RFC-4122.

func FromBytes

func FromBytes(input []byte) (UUID, error)

FromBytes returns a UUID generated from the raw byte slice input. It will return an error if the slice isn't 16 bytes long.

func FromBytesOrNil

func FromBytesOrNil(input []byte) UUID

FromBytesOrNil returns a UUID generated from the raw byte slice input. Same behavior as FromBytes(), but returns uuid.Nil instead of an error.

func FromString

func FromString(input string) (UUID, error)

FromString returns a UUID parsed from the input string. Input is expected in a form accepted by UnmarshalText.

func FromStringOrNil

func FromStringOrNil(input string) UUID

FromStringOrNil returns a UUID parsed from the input string. Same behavior as FromString(), but returns uuid.Nil instead of an error.

func Must

func Must(u UUID, err error) UUID

Must is a helper that wraps a call to a function returning (UUID, error) and panics if the error is non-nil. It is intended for use in variable initializations such as

var packageUUID = uuid.Must(uuid.FromString("123e4567-e89b-12d3-a456-426655440000"))

func NewV1

func NewV1() (UUID, error)

NewV1 returns a UUID based on the current timestamp and MAC address.

func NewV2

func NewV2(domain byte) (UUID, error)

NewV2 returns a DCE Security UUID based on the POSIX UID/GID.

func NewV3

func NewV3(ns UUID, name string) UUID

NewV3 returns a UUID based on the MD5 hash of the namespace UUID and name.

func NewV4

func NewV4() (UUID, error)

NewV4 returns a randomly generated UUID.

func NewV5

func NewV5(ns UUID, name string) UUID

NewV5 returns a UUID based on SHA-1 hash of the namespace UUID and name.

func (UUID) Bytes

func (u UUID) Bytes() []byte

Bytes returns a byte slice representation of the UUID.

func (UUID) MarshalBinary

func (u UUID) MarshalBinary() ([]byte, error)

MarshalBinary implements the encoding.BinaryMarshaler interface.

func (UUID) MarshalText

func (u UUID) MarshalText() ([]byte, error)

MarshalText implements the encoding.TextMarshaler interface. The encoding is the same as returned by the String() method.

func (*UUID) Scan

func (u *UUID) Scan(src interface{}) error

Scan implements the sql.Scanner interface. A 16-byte slice will be handled by UnmarshalBinary, while a longer byte slice or a string will be handled by UnmarshalText.

func (*UUID) SetVariant

func (u *UUID) SetVariant(v byte)

SetVariant sets the variant bits.

func (*UUID) SetVersion

func (u *UUID) SetVersion(v byte)

SetVersion sets the version bits.

func (UUID) String

func (u UUID) String() string

String returns a canonical RFC-4122 string representation of the UUID: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.

func (*UUID) UnmarshalBinary

func (u *UUID) UnmarshalBinary(data []byte) error

UnmarshalBinary implements the encoding.BinaryUnmarshaler interface. It will return an error if the slice isn't 16 bytes long.

func (*UUID) UnmarshalText

func (u *UUID) UnmarshalText(text []byte) error

UnmarshalText implements the encoding.TextUnmarshaler interface. Following formats are supported:

"6ba7b810-9dad-11d1-80b4-00c04fd430c8",
"{6ba7b810-9dad-11d1-80b4-00c04fd430c8}",
"urn:uuid:6ba7b810-9dad-11d1-80b4-00c04fd430c8"
"6ba7b8109dad11d180b400c04fd430c8"
"{6ba7b8109dad11d180b400c04fd430c8}",
"urn:uuid:6ba7b8109dad11d180b400c04fd430c8"

ABNF for supported UUID text representation follows:

URN := 'urn'
UUID-NID := 'uuid'

hexdig := '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' |
          'a' | 'b' | 'c' | 'd' | 'e' | 'f' |
          'A' | 'B' | 'C' | 'D' | 'E' | 'F'

hexoct := hexdig hexdig
2hexoct := hexoct hexoct
4hexoct := 2hexoct 2hexoct
6hexoct := 4hexoct 2hexoct
12hexoct := 6hexoct 6hexoct

hashlike := 12hexoct
canonical := 4hexoct '-' 2hexoct '-' 2hexoct '-' 6hexoct

plain := canonical | hashlike
uuid := canonical | hashlike | braced | urn

braced := '{' plain '}' | '{' hashlike  '}'
urn := URN ':' UUID-NID ':' plain

func (UUID) Value

func (u UUID) Value() (driver.Value, error)

Value implements the driver.Valuer interface.

func (UUID) Variant

func (u UUID) Variant() byte

Variant returns the UUID layout variant.

func (UUID) Version

func (u UUID) Version() byte

Version returns the algorithm version used to generate the UUID.

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