LicenseChecker

LicenseChecker is a command line tool checking licenses of swift package libraries that your app depends on.
It can detect libraries that are not included in a whitelist specifying the license type or library name.

Execution Example

$ license-checker --source-packages-path ~/SourcePackages --white-list-path ~/white-list.json 
✔︎ abseil               Apache
✔︎ BoringSSL-GRPC       BoringSSL
✔︎ Firebase             Apache
✔︎ GoogleAppMeasurement Apache
✔︎ GoogleDataTransport  Apache
✔︎ GoogleUtilities      MIT
✔︎ gRPC                 Apache
✔︎ GTMSessionFetcher    Apache
✔︎ Kanna                MIT
✔︎ KeychainAccess       MIT
✔︎ Kingfisher           MIT
✔︎ leveldb              BSD
✔︎ LicenseList          MIT
✔︎ nanopb               zlib
✔︎ ObjectMapper         MIT
✔︎ Promises             Apache
✔︎ R.swift.Library      MIT
✔︎ Reachability         MIT
✔︎ RxGesture            MIT
✔︎ RxSwift              MIT
✔︎ SwiftProtobuf        Apache
✅ No problems with library licensing.
$

Requirements

• Written in Swift 5
• Compatible with macOS 12.0+
• Development with Xcode 14.2+

How to Use

0. Prepare a white list (white-list.json).

• Specify the type of license to approve.
• Specify the name of library to approve (for private libraries).

LicenseChecker supports the following licenses:

license type	white list key
Apache license 2.0	Apache
MIT License	MIT
BSD 3-clause Clear license	BSD
zLib License	zlib
BoringSSL	BoringSSL

Sample of white-list.json

{
  "licenses": [
    "Apache", 
    "MIT", 
    "BSD",  
    "zlib",
    "BoringSSL"
  ],
  "libraries": [
    "PrivateLibrary-Hoge"
  ]
}

CommandPlugin & Run Script in BuildPhases (for Xcode Project)

1. Add binary target & plugin to Package.swift.

   targets: [
       .binaryTarget(
           name: "license-checker",
           url: "https://github.com/cybozu/LicenseChecker/releases/download/1.2.0/license-checker-macos.artifactbundle.zip",
           checksum: "4b3aacb1c2b2b91012db0b13680eba82f79a779c7271d086e12028901ada71b5"
       ),
       .plugin(
           name: "LicenseCheckerCommand",
           capability: .command(
               intent: .custom(verb: "license-checker", description: "Run LicenseChecker"),
               permissions: []
           ),
           dependencies: ["license-checker"]
       )
   ]

2. Code Plugins/LicenseCheckerCommand/main.swift.

   import Foundation
   import PackagePlugin
   
   @main
   struct LicenseCheckerCommand: CommandPlugin {
       func performCommand(context: PluginContext, arguments: [String]) async throws {
           let licenseCheckerPath = try context.tool(named: "license-checker").path.string
           let rswiftURL = URL(fileURLWithPath: licenseCheckerPath, isDirectory: false)
   
           let process = try Process.run(rswiftURL, arguments: arguments)
           process.waitUntilExit()
   
           if process.terminationReason != .exit || process.terminationStatus != 0 {
               Diagnostics.error("license-checker errors detected.")
           }
       }
   }

3. Add a Run Script in BuildPhases

   SOURCE_PACKAGES_PATH=`echo ${BUILD_DIR%Build/*}SourcePackages`
   xcrun --sdk macosx swift package --package-path ./RoadWarriorPackages \
   --allow-writing-to-directory ${SRCROOT} \
   license-checker -s ${SOURCE_PACKAGES_PATH} -w [Path to white-list.json]

BuildToolPlugin (for Swift Package Project)

1. Add binary target & plugin to Package.swift.

   targets: [
       .binaryTarget(
           name: "license-checker",
           url: "https://github.com/cybozu/LicenseChecker/releases/download/1.2.0/license-checker-macos.artifactbundle.zip",
           checksum: "4b3aacb1c2b2b91012db0b13680eba82f79a779c7271d086e12028901ada71b5"
       ),
       .plugin(
           name: "LicenseCheckerPlugin",
           capability: .buildTool(),
           dependencies: [
               .target(name: "license-checker")
           ]
       )
   ]

2. Code Plugins/LicenseCheckerPlugin/main.swift.

   import Foundation
   import PackagePlugin
   
   @main
   struct LicenseCheckerPlugin: BuildToolPlugin {
       struct SourcePackagesNotFoundError: Error & CustomStringConvertible {
           let description: String = "SourcePackages not found"
       }
   
       func sourcePackages(_ pluginWorkDirectory: Path) throws -> Path {
           var tmpPath = pluginWorkDirectory
           guard pluginWorkDirectory.string.contains("SourcePackages") else {
               throw SourcePackagesNotFoundError()
           }
           while tmpPath.lastComponent != "SourcePackages" {
               tmpPath = tmpPath.removingLastComponent()
           }
           return tmpPath
       }
   
       func createBuildCommands(context: PluginContext, target: Target) async throws -> [Command] {
           let executablePath = try context.tool(named: "license-checker").path
           let sourcePackagesPath = try sourcePackages(context.pluginWorkDirectory)
           let whiteListPath = "Path to white-list.json" // Please change accordingly.
   
           return [
               .prebuildCommand(
                   displayName: "Prepare LicenseList",
                   executable: executablePath,
                   arguments: [
                       "--source-packages-path",
                       sourcePackagesPath.string,
                       "--white-list-path",
                       whiteListPath
                   ],
                   outputFilesDirectory: context.pluginWorkDirectory
               )
           ]
       }
   }

3. Use plugin in the target (Package.swift).

   targets: [
       .target(
           name: "SomeFeature",
           resources: [.process("white-list.json")], // Please change accordingly.
           plugins: [
               .plugin(name: "LicenseCheckerPlugin")
           ]
       )
   ]

license-checker (command help)

$ swift run license-checker -h
Building for debugging...
Build complete! (0.10s)
OVERVIEW: A tool to check license of swift package libraries.

USAGE: license-checker --source-packages-path <source-packages-path> --white-list-path <white-list-path>

OPTIONS:
  -s, --source-packages-path <source-packages-path>
                          Path to SourcePackages directory
  -w, --white-list-path <white-list-path>
                          Path to white-list.json
  --version               Show the version.
  -h, --help              Show help information.