Automating iOS builds

Building an app on iOS is a hodge-podge of 2 VMs and too many bash scripts. It all starts with buildserver-build-ios.sh. It does 2 main things:

• polls the app repo
• tries to build well signed tags that match ^ios/ with run-build-and-upload.sh.

Well signed in this case implies that the tag has been signed by a GPG key that is signed by Mullvad's code signing key.

run-build-and-upload.sh

This script builds the iOS app archive in one VM, which has our app signing keys, and uploads the resulting archive in the upload VM, which has our AppStoreConnect API keys. This segregation is intentional, compromising the build VM won't allow an attacker to take down our app store listing, compromising the upload VM won't allow the attacker to compromise our signing keys.

The script uses run-in-vm.sh to execute scripts inside these 2 VMs:

• build-app.sh is executed in the build VM, which eventually executes ios/build.sh.
• upload-app.sh is executed in the upload VM