Golang Password Generator

This library implements generation of random passwords with provided requirements as described by AgileBits 1Password in pure Golang. The algorithm is commonly used when generating website passwords.

The library uses crypto/rand for added randomness.

Sample example passwords this library may generate:

0N[k9PhDqmmfaO`p_XHjVv`HTq|zsH4XiH8umjg9JAGJ#\Qm6lZ,28XF4{X?3sHj
7@90|0H7!4p\,c<!32:)0.9N
UlYuRtgqyWEivlXnLeBpZvIQ
Q795Im1VR5h363s48oZGaLDa
wpvbxlsc

Since these are completely randomized, it's possible that they may generate passwords that don't comply with some custom password policies, such as ones that require both upper case AND lower case letters. If your particular use case needs a mix of casing, then you can either increase the number of characters in the password or check the output and regenerate if it fails a particular constraint, such as requiring both upper and lower case.

Installation

$ go get -u github.com/sethvargo/go-password/password

Usage

package main

import (
  "log"

  "github.com/sethvargo/go-password/password"
)

func main() {
  // Generate a password that is 64 characters long with 10 digits, 10 symbols,
  // allowing upper and lower case letters, disallowing repeat characters.
  res, err := password.Generate(64, 10, 10, false, false)
  if err != nil {
    log.Fatal(err)
  }
  log.Printf(res)
}

See the GoDoc for more information.

Testing

For testing purposes, instead of accepted a *password.Generator struct, accept a password.PasswordGenerator interface:

// func MyFunc(p *password.Generator)
func MyFunc(p password.PasswordGenerator) {
  // ...
}

Then, in tests, use a mocked password generator with stubbed data:

func TestMyFunc(t *testing.T) {
  gen := password.NewMockGenerator("canned-response", false)
  MyFunc(gen)
}

In this example, the mock generator will always return the value "canned-response", regardless of the provided parameters.

License

This code is licensed under the MIT license.