fastid's Introduction

FastID -- Snowflake ID generating in Go

FastID is a pluggable unique ID generator in Go.

Under 64 bits (Long Integer)
K-Ordered
Lock-free (using atomic CAS)
Decentralized

Installation

go get github.com/beinan/fastid

Quick Start

Generate an ID

import (
  "fmt"
  "github.com/beinan/fastid"
)

func ExampleGenInt64ID() {
  id := fastid.CommonConfig.GenInt64ID()
  fmt.Printf("id generated: %v", id)
}

Recommended Settings

40 bits timestamp (34 years from 2018-06-01)
16 bits machine ID (using lower 16 bits of IP v4 addr as default)
7 bits sequence number

With this setting, FastID is able to generate 128(2^7) unique IDs per millisecond (1.048576 millisecond, 2^10 nanosecond).

Customized Settings

See the examples in GoDoc

Benchmarks

Benchmark Settings

40 bits timestamp (34 years from 2018-06-01)
8 bits machine ID
15 bits sequence number

go test -bench=.
goos: linux
goarch: amd64
pkg: github.com/beinan/fastid
BenchmarkGenID-4        20000000                79.7 ns/op
BenchmarkGenIDP-4       20000000               141 ns/op
PASS
ok      github.com/beinan/fastid        4.779s

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fastid's Issues

Custom "StartTimeEnvName" not work

Custom "StartTimeEnvName" not work.

func getStartEpochFromEnv() int64 {
	startTimeStr := getEnv(StartTimeEnvName, defaultStartTimeStr)
	var startEpochTime, err = time.Parse(time.RFC3339, startTimeStr)

	if err == nil {
		return defaultStartTimeNano
	}

	return startEpochTime.UnixNano()
}

I think is err != nil, or custom config StartTimeEnvName will not work.
When StartTimeEnvName is valid time format, err will be nil, and return defaultStartTimeNao instead of my config.