Categorygithub.com/effective-security/xflake
package
0.6.41
Repository: https://github.com/effective-security/x.git
Documentation: pkg.go.dev
Overview
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Dependencies
7
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206 SLOC

# README

Flake

A fork from https://github.com/sony/sonyflake

Flake is a distributed unique ID generator inspired by Twitter's Snowflake.

Differences from the original Sonyflake:

  • panic instead of returning errors, as these errors are mostly non actionable and should never occur: NextID() uint64
  • time units are 1 msec instead of 10
  • 16 bits for a machine id,
  • 6 bits for a sequence number (64 per 1 ms)
  • 41 bits for time in units of 1 msec

As a result, Flake has the following advantages and disadvantages:

  • The lifetime (69 years) is similar to that of Snowflake (69 years)
  • It can work on more distributed machines (2^16) than Snowflake (2^10)
  • It can generate 2^6 IDs per 1 msec at most in a single machine/thread

Installation

go get github.com/effective-security/porto/pkg/flake

Usage

The function NewIDGenerator creates a new IDGenerator instance.

func NewIDGenerator(st Settings) IDGenerator

You can configure Flake by the struct Settings:

type Settings struct {
	StartTime      time.Time
	MachineID      func() (uint16, error)
	CheckMachineID func(uint16) bool
}

  • StartTime is the time since which the Flake time is defined as the elapsed time. If StartTime is 0, the start time of the Sonyflake is set to "2021-01-01 00:00:00 +0000 UTC". If StartTime is ahead of the current time, Flake is not created.

  • MachineID returns the unique ID of the Flake instance. If MachineID returns an error, Flake will panic. If MachineID is nil, default MachineID is used. Default MachineID returns the lower 8 bits of the private IP address.

  • CheckMachineID validates the uniqueness of the machine ID. If CheckMachineID returns false, Flake will panic. If CheckMachineID is nil, no validation is done.

In order to get a new unique ID, you just have to call the method NextID.

func (sf *Flake) NextID() uint64

License

The MIT License (MIT)

# Functions

Decompose returns a set of Flake ID parts.
FirstID returns the first ID generated by the generator.
IDTime returns the timestamp of the flake ID.
IsTestRun returns true if the program is running in the test.
LastID returns the last ID generated by the generator.
NewIDGenerator returns a new Flake configured with the given Settings.

# Constants

bit length of machine id, 2^16.
bit length of sequence number.
bit length of time.
These constants are the bit lengths of Flake ID parts.
These constants are the bit lengths of Flake ID parts.
These constants are the bit lengths of Flake ID parts.
These constants are the bit lengths of Flake ID parts.

# Variables

DefaultIDGenerator for the app.
DefaultStartTime provides default start time for the Flake.
NowFunc returns the current time; it's overridden in tests.

# Structs

Flake is a distributed unique ID generator.
Settings configures Flake: StartTime is the time since which the Flake time is defined as the elapsed time.

# Interfaces

IDGenerator defines an interface to generate unique ID accross the cluster.