Documentation
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Overview ¶
Package uuid generates and inspects UUIDs.
UUIDs are based on RFC 4122 and DCE 1.1: Authentication and Security Services.
A UUID is a 16 byte (128 bit) array. UUIDs may be used as keys to maps or compared directly.
Index ¶
- Constants
- Variables
- func ClockSequence() int
- func NodeID() []byte
- func NodeInterface() string
- func SetClockSequence(seq int)
- func SetNodeID(id []byte) bool
- func SetNodeInterface(name string) bool
- func SetRand(r io.Reader)
- type Domain
- type Time
- type UUID
- func FromBytes(b []byte) (uuid UUID, err error)
- func Must(uuid UUID, err error) UUID
- func MustParse(s string) UUID
- func New() UUID
- func NewDCEGroup() (UUID, error)
- func NewDCEPerson() (UUID, error)
- func NewDCESecurity(domain Domain, id uint32) (UUID, error)
- func NewHash(h hash.Hash, space UUID, data []byte, version int) UUID
- func NewMD5(space UUID, data []byte) UUID
- func NewRandom() (UUID, error)
- func NewRandomFromReader(r io.Reader) (UUID, error)
- func NewSHA1(space UUID, data []byte) UUID
- func NewUUID() (UUID, error)
- func Parse(s string) (UUID, error)
- func ParseBytes(b []byte) (UUID, error)
- func (uuid UUID) ClockSequence() int
- func (uuid UUID) Domain() Domain
- func (uuid UUID) ID() uint32
- func (uuid UUID) MarshalBinary() ([]byte, error)
- func (uuid UUID) MarshalText() ([]byte, error)
- func (uuid UUID) NodeID() []byte
- func (uuid *UUID) Scan(src interface{}) error
- func (uuid UUID) String() string
- func (uuid UUID) Time() Time
- func (uuid UUID) URN() string
- func (uuid *UUID) UnmarshalBinary(data []byte) error
- func (uuid *UUID) UnmarshalText(data []byte) error
- func (uuid UUID) Value() (driver.Value, error)
- func (uuid UUID) Variant() Variant
- func (uuid UUID) Version() Version
- type Variant
- type Version
Constants ¶
Domain constants for DCE Security (Version 2) UUIDs.
const ( Invalid = Variant(iota) // Invalid UUID RFC4122 // The variant specified in RFC4122 Reserved // Reserved, NCS backward compatibility. Microsoft // Reserved, Microsoft Corporation backward compatibility. Future // Reserved for future definition. )
Constants returned by Variant.
Variables ¶
var ( NameSpaceDNS = Must(Parse("6ba7b810-9dad-11d1-80b4-00c04fd430c8")) NameSpaceURL = Must(Parse("6ba7b811-9dad-11d1-80b4-00c04fd430c8")) NameSpaceOID = Must(Parse("6ba7b812-9dad-11d1-80b4-00c04fd430c8")) NameSpaceX500 = Must(Parse("6ba7b814-9dad-11d1-80b4-00c04fd430c8")) Nil UUID // empty UUID, all zeros )
Well known namespace IDs and UUIDs
Functions ¶
func ClockSequence ¶
func ClockSequence() int
ClockSequence returns the current clock sequence, generating one if not already set. The clock sequence is only used for Version 1 UUIDs.
The uuid package does not use global static storage for the clock sequence or the last time a UUID was generated. Unless SetClockSequence is used, a new random clock sequence is generated the first time a clock sequence is requested by ClockSequence, GetTime, or NewUUID. (section 4.2.1.1)
func NodeID ¶
func NodeID() []byte
NodeID returns a slice of a copy of the current Node ID, setting the Node ID if not already set.
func NodeInterface ¶
func NodeInterface() string
NodeInterface returns the name of the interface from which the NodeID was derived. The interface "user" is returned if the NodeID was set by SetNodeID.
func SetClockSequence ¶
func SetClockSequence(seq int)
SetClockSequence sets the clock sequence to the lower 14 bits of seq. Setting to -1 causes a new sequence to be generated.
func SetNodeID ¶
SetNodeID sets the Node ID to be used for Version 1 UUIDs. The first 6 bytes of id are used. If id is less than 6 bytes then false is returned and the Node ID is not set.
func SetNodeInterface ¶
SetNodeInterface selects the hardware address to be used for Version 1 UUIDs. If name is "" then the first usable interface found will be used or a random Node ID will be generated. If a named interface cannot be found then false is returned.
SetNodeInterface never fails when name is "".
Types ¶
type Time ¶
type Time int64
A Time represents a time as the number of 100's of nanoseconds since 15 Oct 1582.
func GetTime ¶
GetTime returns the current Time (100s of nanoseconds since 15 Oct 1582) and clock sequence as well as adjusting the clock sequence as needed. An error is returned if the current time cannot be determined.
type UUID ¶
type UUID [16]byte
A UUID is a 128 bit (16 byte) Universal Unique IDentifier as defined in RFC 4122.
func FromBytes ¶
FromBytes creates a new UUID from a byte slice. Returns an error if the slice does not have a length of 16. The bytes are copied from the slice.
func Must ¶
Must returns uuid if err is nil and panics otherwise.
func MustParse ¶
MustParse is like Parse but panics if the string cannot be parsed. It simplifies safe initialization of global variables holding compiled UUIDs.
func New ¶
func New() UUID
New creates a new random UUID or panics. New is equivalent to the expression
uuid.Must(uuid.NewRandom())
func NewDCEGroup ¶
NewDCEGroup returns a DCE Security (Version 2) UUID in the group domain with the id returned by os.Getgid.
NewDCESecurity(Group, uint32(os.Getgid()))
func NewDCEPerson ¶
NewDCEPerson returns a DCE Security (Version 2) UUID in the person domain with the id returned by os.Getuid.
NewDCESecurity(Person, uint32(os.Getuid()))
func NewDCESecurity ¶
NewDCESecurity returns a DCE Security (Version 2) UUID.
The domain should be one of Person, Group or Org. On a POSIX system the id should be the users UID for the Person domain and the users GID for the Group. The meaning of id for the domain Org or on non-POSIX systems is site defined.
For a given domain/id pair the same token may be returned for up to 7 minutes and 10 seconds.
func NewHash ¶
NewHash returns a new UUID derived from the hash of space concatenated with data generated by h. The hash should be at least 16 byte in length. The first 16 bytes of the hash are used to form the UUID. The version of the UUID will be the lower 4 bits of version. NewHash is used to implement NewMD5 and NewSHA1.
func NewMD5 ¶
NewMD5 returns a new MD5 (Version 3) UUID based on the supplied name space and data. It is the same as calling:
NewHash(md5.New(), space, data, 3)
func NewRandom ¶
NewRandom 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.
func NewRandomFromReader ¶
NewRandomFromReader returns a UUID based on bytes read from a given io.Reader.
func NewSHA1 ¶
NewSHA1 returns a new SHA1 (Version 5) UUID based on the supplied name space and data. It is the same as calling:
NewHash(sha1.New(), space, data, 5)
func NewUUID ¶
NewUUID returns a Version 1 UUID based on the current NodeID and clock sequence, and the current time. If the NodeID has not been set by SetNodeID or SetNodeInterface then it will be set automatically. If the NodeID cannot be set NewUUID returns nil. If clock sequence has not been set by SetClockSequence then it will be set automatically. If GetTime fails to return the current NewUUID returns nil and an error.
In most cases, New should be used.
func Parse ¶
Parse 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 ParseBytes ¶
ParseBytes is like Parse, except it parses a byte slice instead of a string.
func (UUID) ClockSequence ¶
ClockSequence returns the clock sequence encoded in uuid. The clock sequence is only well defined for version 1 and 2 UUIDs.
func (UUID) Domain ¶
Domain returns the domain for a Version 2 UUID. Domains are only defined for Version 2 UUIDs.
func (UUID) ID ¶
ID returns the id for a Version 2 UUID. IDs are only defined for Version 2 UUIDs.
func (UUID) MarshalBinary ¶
MarshalBinary implements encoding.BinaryMarshaler.
func (UUID) MarshalText ¶
MarshalText implements encoding.TextMarshaler.
func (UUID) NodeID ¶
NodeID returns the 6 byte node id encoded in uuid. It returns nil if uuid is not valid. The NodeID is only well defined for version 1 and 2 UUIDs.
func (*UUID) Scan ¶
Scan implements sql.Scanner so UUIDs can be read from databases transparently Currently, database types that map to string and []byte are supported. Please consult database-specific driver documentation for matching types.
func (UUID) String ¶
String returns the string form of uuid, xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx , or "" if uuid is invalid.
func (UUID) Time ¶
Time returns the time in 100s of nanoseconds since 15 Oct 1582 encoded in uuid. The time is only defined for version 1 and 2 UUIDs.
func (UUID) URN ¶
URN returns the RFC 2141 URN form of uuid, urn:uuid:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx, or "" if uuid is invalid.
func (*UUID) UnmarshalBinary ¶
UnmarshalBinary implements encoding.BinaryUnmarshaler.
func (*UUID) UnmarshalText ¶
UnmarshalText implements encoding.TextUnmarshaler.
func (UUID) Value ¶
Value implements sql.Valuer so that UUIDs can be written to databases transparently. Currently, UUIDs map to strings. Please consult database-specific driver documentation for matching types.
func (UUID) Variant ¶
Variant returns the variant encoded in uuid.
Source Files