glicense - Go Binary OSS License Scanner

glicense is a highly modified version of mitchellih/golicense that scans compiled Go binaries and can output all the dependencies, their versions, and their respective licenses (if known). This version of glicense scans project directories for go.mod files instead of scanning the final binary or binaries.

glicense determines the dependency list quickly and with exact accuracy since it uses metadata from the Go compiler to determine the exact set of dependencies embedded in a compiled Go binary. This excludes dependencies that are not used in the final binary. For example, if a library depends on "foo" in function "F" but "F" is never called, then the dependency "foo" will not be present in the final binary.

glicense is not meant to be a complete replacement for open source compliance companies such as FOSSA or BlackDuck, both of which provide hundreds of additional features related to open source compliance.

Features

• List dependencies and their associated licenses
• Cross-reference dependency licenses against an allow/deny list
• Output reports in the terminal and Excel (XLSX) format
• Manually specify overrides for specific dependencies if the detection is incorrect.

Installation

To install glicense, download the appropriate release for your platform from the releases page.

You can also compile from source using Go 1.17 or later using standard go build.

Usage

glicense is used with one or two required arguments. In the one-argument form, the dependencies and their licenses are listed. In the two-argument form, a configuration file can be given to specify an allow/deny list of licenses and more.

$ glicense [flags] [DIRECTORY]
$ glicense [flags] [CONFIG] [DIRECTORY]

You may also pass mutliple binaries (but only if you are providing a CONFIG).

Configuration File

The configuration file can specify allow/deny lists of licenses for reports, license overrides for specific dependencies, and more. The configuration file format is HCL or JSON.

Example:

allow = ["MIT", "Apache-2.0"]
deny  = ["GNU General Public License v2.0"]

{
  "allow": ["MIT", "Apache-2.0"],
  "deny": ["GNU General Public License v2.0"]
}

Supported configurations:

• allow (array<string>) - A list of names or SPDX IDs of allowed licenses.
• deny (array<string>) - A list of names or SPDX IDs of denied licenses.
• override (map<string, string>) - A mapping of Go import identifiers to translate into a specific license by SPDX ID. This can be used to set the license of imports that glicense cannot detect so that reports pass.
• translate (map<string, string>) - A mapping of Go import identifiers to translate into alternate import identifiers. Example: "gopkg.in/foo/bar.v2" to "github.com/foo/bar". If the map key starts and ends with / then it is treated as a regular expression. In this case, the map value can use \1, \2, etc. to reference capture groups.

GitHub Authentication

glicense uses the GitHub API to look up licenses. This doesn't require any authentication out of the box but will be severely rate limited. It is recommended that you generate a personal access token to increase the rate limit. The personal access token doesn't require any special access unless it needs to look at private repositories you have access to, in which case it should be granted the repo permission. Specify your token using the GITHUB_TOKEN environment variable.

$ export GITHUB_TOKEN=abcd1234
$ glicense ./binary

Excel (XLSX) Reporting Output

If the -out-xlsx flag is specified, then an Excel report is generated and written to the path specified in addition to the terminal output.

$ glicense -out-xlsx=report.xlsx ./my-program

The Excel report contains the list of dependencies, their versions, the detected license, and whether the license is allowed or not. The dependencies are listed in alphabetical order. The row of the dependency will have a green background if everything is okay, a yellow background if a license is unknown, or a red background is a license is denied. An example screenshot is shown below:

Limitations

There are a number of limitations to glicense currently. These are fixable but work hasn't been done to address these yet. If you feel like taking a stab at any of these, please do and contribute!

GitHub API: The license detected by glicense may be incorrect if a GitHub project changes licenses. glicense uses the GitHub API which only returns the license currently detected; we can't lookup licenses for specific commit hashes.