Golang Password Generator

jms included in Golang

2026-07-01 244 words 2 minutes

Contents

I continue learning Go, so this time I created a password generator to generate secure passwords that exclude ambiguous characters

Features

Generate multiple passwords at once.
Customizable password length (minimum 8 characters).
Excludes ambiguous characters (e.g., 0, 1, O, I, l, 5, S, q, g).
Memory efficient

Implementation Details

To make the development easy and more maintainable creating a modern CLI tool I use spf13/cobra, Cobra framework and keep the dependencies at minimum with crypto/rand for cryptographically secure random number generation and strings.Builder for efficient string construction.

The code is available here https://github.com/jms/passwordGenerator

Build/Development (Linux)

the executable can be built using go, or for convenience use the makefile and run make

# get the dependencies 
go mod tidy

# then 
go build -o password-gen

# or 
make
go build -o password-gen


# running the unit tests
make test
go test -v
=== RUN   TestValidateInput
=== RUN   TestValidateInput/Valid_input
=== RUN   TestValidateInput/Minimum_length
=== RUN   TestValidateInput/Invalid_count_(zero)
=== RUN   TestValidateInput/Invalid_count_(negative)
=== RUN   TestValidateInput/Invalid_length_(too_short)
--- PASS: TestValidateInput (0.00s)
    --- PASS: TestValidateInput/Valid_input (0.00s)
    --- PASS: TestValidateInput/Minimum_length (0.00s)
    --- PASS: TestValidateInput/Invalid_count_(zero) (0.00s)
    --- PASS: TestValidateInput/Invalid_count_(negative) (0.00s)
    --- PASS: TestValidateInput/Invalid_length_(too_short) (0.00s)
=== RUN   TestGeneratePassword
=== RUN   TestGeneratePassword/Valid_length_16
=== RUN   TestGeneratePassword/Valid_length_8_(min)
--- PASS: TestGeneratePassword (0.00s)
    --- PASS: TestGeneratePassword/Valid_length_16 (0.00s)
    --- PASS: TestGeneratePassword/Valid_length_8_(min) (0.00s)
=== RUN   TestGeneratePasswords
--- PASS: TestGeneratePasswords (0.00s)
PASS
ok      passwordGenerator       0.003s

Demo

time ./password-gen -n 1000000 
...

________________________________________________________
Executed in    3.57 secs    fish           external
   usr time    2.66 secs  882.00 micros    2.65 secs
   sys time    1.26 secs    7.00 micros    1.26 secs