licensepack

licensepack

licensepack generates a text file containing licensing information for all dependencies used by your Go project. This should help distributors of your software follow the terms of most open source licenses.

Usage

licensepack is intended to be run as a go-generate script. Start by adding licensepack to your go.mod file:

go get -tool github.com/paulhammond/licensepack

Then add a go-generate line to your code:

//go:generate go tool licensepack ./path/to/main

Then run go generate:

go generate ./...

A file called credits.txt will be created with contents looking something like this:

## github.com/your/package

LICENSE:

Copyright (c) 2021 Your Name. All rights reserved.
…

You can then use the embed package to make that file available in your code:

//go:embed credits.txt
var credits string

Then you can add some code to output the contents of that variable, perhaps if a command line flag is provided:

func main(){
	…
	var showCredits = flag.Bool("credits", false, "show open source credits")

	flag.Parse()
	if *showCredits {
		fmt.Println(credits)
		os.Exit(0)
	}
	…
}

A complete example is available in examples/hello.

Built in templates

licensepack uses text/template, allowing you to customize the output to meet your needs. A few built in templates are provided which provide differing levels of repetitiveness:

//go:generate go tool licensepack -tmpl short path/to/main
//go:generate go tool licensepack -tmpl long path/to/main

Custom templates

If you’d like to customize the template you can provide the path to a template file. For example:

//go:generate go tool licensepack -tmpl ./licenses.tmpl .

A complete example is provided in examples/custom. The built in templates can be used as a starting point and hopefully demonstrate usage of the available template helper functions.

Alternatives

go-licenses can generate similar reports to licensepack (see the markdown example in the README). It has a lot of additional functionality that licensepack lacks, including the ability to detect a name for each license, but also has a lot of dependencies. If licencepack doesn't have the functionality you need then this is likely the best option for you.

go-licence-detector also generates license notices. It has many options not available in licensepack, but invocation is more complex and, at the time of writing, includes indirect dependencies that are not actually linked into the compiled binary.

Credits/License

Run licensepack -credits for license information.