This journey started with my naive idea that I could do all of this outside of Macintosh/MacOS. It started out great when I found Apple's Notary API, so I wrote macosnotarylib. But I also needed binary and package signing, and I gave up the grand idea. There are some third party libraries that claim to do some of this, but for me, even getting passed the trust part where I would have to inspect the code, would be too much work.

So, I wrote some tooling for this myself that uses Apple's CLI tools and API, and this library is the core part of it. There are Go alternatives out there, most notably gon. The biggest difference is that gon produces DMG or ZIP files. This library produces the very end-user-friendly PKG format.

The bulding blocks:

• Running buildpkg.New(opts).Build() will
  1. Sign the binary with codesign
  2. Package the binary with pkgbuild
  3. Sign the package with productsign
  4. Check the package with pkgutil
  5. Notarize the package with macosnotarylib (uses the Apple API)
  6. Staple the package with stapler

For the codesign step you need create a Developer ID Application Certificate and for the package signing step you need a Developer ID Installer Certificate. These needs to be imported into your Keychain. Follow the instructions at developer.apple.com.

Once you have those imported in the Keychain you can locate their common signing identity with security find-identity -v, which is XYZJUFSYL4 in the example below:

~/d/g/hugoreleaser ❯❯❯ security find-identity -v
  1) D4A412805301423E2DF63D90CE37C8A050B3AA2F "Developer ID Application: Bjørn Erik Pedersen (XYZJUFSYL4)"
  2) D4A412805301423E2DF63D90CE37C8A050B3AA2F "Developer ID Application: Bjørn Erik Pedersen (XYZJUFSYL4)"
  3) EADAD38B73CADB2E6975F55B8735F17B09138217 "Developer ID Installer: Bjørn Erik Pedersen (XYZJUFSYL4)"
  4) EADAD38B73CADB2E6975F55B8735F17B09138217 "Developer ID Installer: Bjørn Erik Pedersen (XYZJUFSYL4)"
     4 valid identities found

For the notarizer step you need to create a new new API access key with Developer access and download the private key. Take note of the Issuer ID and Key ID:

Also See Creating API Keys for App Store Connect AP.

With the above you could put the signing identity in the Options struct and pass it to New:

type Options struct {
	// The Info logger.
	// If nil, no Info logging will be done.
	Infof func(format string, a ...interface{})

	// The Dir to build from.
	Dir string

	// Developer ID Application + Developer ID Installer
	// https://developer.apple.com/account/resources/certificates/list
	SigningIdentity string

	// The result
	PackageOutputFilename string

	// The staging directory where all your build artifacts are located.
	StagingDirectory string

	// E.g. io.gohugo.hugo
	Identifier string

	// E.g. 234
	Version string

	// E.g. /usr/local/bin
	InstallLocation string

	// Scripts passed on the command line --scripts flag.
	// E.g. /mypkgscripts
	ScriptsDirectory string

	// Flags to enable skipping of build steps.
	SkipCodeSigning      bool
	SkipInstallerSigning bool
	SkipNotarization     bool
}

The other settings currently needs to be set as OS environment variables:

• MACOSNOTARYLIB_ISSUER_ID
• MACOSNOTARYLIB_KID (Key ID)
• MACOSNOTARYLIB_PRIVATE_KEY (in base64 format).

Use with Hugoreleaser

There are 2 archive plugins available:

• macospkgremote
• macospkg (a "local" variant of the above)

Also see it configured in Hugoreleaser's build config.