xrand

README

Xrand

---

Package xrand contains some randomize utilities like a random string generator, a jitter function for durations.
It uses math rand seeded with a crypro rand generated seed. See go doc reference for more details and examples.

Installation

$ go get github.com/actforgood/xrand

Misc

Feel free to use this pkg if you like it and fits your needs.
As it is a light/lite pkg, you can also just copy-paste the code, instead of importing it, keeping the license header.

License

This package is released under a MIT license. See LICENSE.

Documentation

Overview

Package xrand contains some randomize utilities like a random string generator, a jitter function for durations. It uses math rand seeded with a crypro rand generated seed.

Index

• Constants
• func Float64() float64
• func Intn(n int) int
• func IntnBetween(min, max int) int
• func Jitter(duration time.Duration, maxFactor ...float64) time.Duration
• func String(n int, alphabet ...string) string

Examples

• Float64
• Intn
• IntnBetween
• Jitter
• String

Constants

const (
	// AlphanumAlphabet consists of Ascii lowercase letters, and digits.
	AlphanumAlphabet = "abcdefghijklmnopqrstuvwxyz0123456789"
	// DigitsAlphabet consists of 1..9 numbers.
	DigitsAlphabet = "0123456789"
)

Functions

func Float64

func Float64() float64

Float64 generates a random float64 in range [0.0, 1.0).

Example

package main

import (
	"fmt"

	"github.com/actforgood/xrand"
)

func main() {
	// generate a random float in [0.0, 1.0)
	randFloat := xrand.Float64()
	fmt.Println(randFloat)
}

func Intn

func Intn(n int) int

Intn generates a random integer in range [0,n). It panics if max <= 0.

Example

package main

import (
	"fmt"

	"github.com/actforgood/xrand"
)

func main() {
	// generate a random int in [0, 1000)
	randInt := xrand.Intn(1000)
	fmt.Println(randInt)
}

func IntnBetween

func IntnBetween(min, max int) int

IntnBetween generates a random integer in range [min,max). It panics if max <= 0.

Example

package main

import (
	"fmt"

	"github.com/actforgood/xrand"
)

func main() {
	// generate a random int in [100, 200)
	randInt := xrand.IntnBetween(100, 200)
	fmt.Println(randInt)
}

func Jitter

func Jitter(duration time.Duration, maxFactor ...float64) time.Duration

Jitter returns a time.Duration altered with a random factor. This allows clients to avoid converging on periodic behaviour. If maxFactor is <= 0.0, a suggested default value will be chosen.

Example

package main

import (
	"fmt"
	"time"

	"github.com/actforgood/xrand"
)

func main() {
	// slightly alter +/- a time.Duration
	cacheTTL := 10 * time.Minute
	factor := 0.1
	jitteredCacheTTL := xrand.Jitter(cacheTTL, factor)
	fmt.Println(jitteredCacheTTL)
}

func String

func String(n int, alphabet ...string) string

String generates a random string of length n with letters from the alphabet. Alphabet is optional and defaults to AlphanumAlphabet if not provided.

Example

package main

import (
	"fmt"

	"github.com/actforgood/xrand"
)

func main() {
	// generate a random string of length 16, containing [a-z0-9] letters.
	randString := xrand.String(16, xrand.AlphanumAlphabet)
	fmt.Println(randString)
}