Customising unbound build for MacOS on M1 using homebrew tooling

Got broken package and got stuck on how to fix it? Let's get it back to life by using example of unbound package.

First you will need to remove the package you already have in your system:

brew remove unbound

Then you should create a new local tap for your customisation

brew tap-new $USER/local-unbound

The successful output will be looking like (replace <user> by your real username):

Initialized empty Git repository in /opt/homebrew/Library/Taps/<user>/homebrew-local-unbound/.git/
[main (root-commit) 5317ce5] Create <user>/local-unbound tap
3 files changed, 90 insertions(+)
create mode 100644 .github/workflows/publish.yml
create mode 100644 .github/workflows/tests.yml
create mode 100644 README.md
==> Created <user>/local-unbound
/opt/homebrew/Library/Taps/<user>/homebrew-local-unbound
When a pull request making changes to a formula (or formulae) becomes green (all checks passed), then you can publish the built bottles.
To do so, label your PR as `pr-pull` and the workflow will be triggered.

Now you should clone your package from some exisiting point. In our example we are going to restore version 1.7.1 of the package:

brew extract --version=1.7.1 unbound $USER/local-unbound
==> Searching repository history
==> Writing formula for unbound from revision 512758e to:
/opt/homebrew/Library/Taps/<user>/homebrew-local-unbound/Formula/unbound@1.7.1.rb

The package may won’t install because of error like (plist_options was deprecated time ago, and now it is completely disabled):

Error: unbound@1.7.1: Calling plist_options is disabled! Use service.require_root instead.

So, edit the formula to match the homebrew rules and to fit your needs (file /opt/homebrew/Library/Taps/<user>/homebrew-local-unbound/Formula/unbound@1.7.1.rb). Example:

class UnboundAT171 < Formula
  desc "Validating, recursive, caching DNS resolver"
  homepage "https://www.unbound.net"
  url "https://www.unbound.net/downloads/unbound-1.7.1.tar.gz"
  sha256 "56e085ef582c5372a20207de179d0edb4e541e59f87be7d4ee1d00d12008628d"

  deprecated_option "with-python" => "with-python@2"

  depends_on "openssl"
  depends_on "libevent"
  depends_on "expat"
  depends_on "python@2" => :optional
  depends_on "swig" if build.with? "python@2"

  def install
    args = %W[
      --prefix=#{prefix}
      --sysconfdir=#{etc}
      --with-libevent=#{Formula["libevent"].opt_prefix}
      --with-ssl=#{Formula["openssl"].opt_prefix}
      --with-libexpat=#{Formula["expat"].opt_prefix}
    ]

    if build.with? "python@2"
      ENV.prepend "LDFLAGS", `python-config --ldflags`.chomp
      ENV.prepend "PYTHON_VERSION", "2.7"

      args << "--with-pyunbound"
      args << "--with-pythonmodule"
      args << "PYTHON_SITE_PKG=#{lib}/python2.7/site-packages"
    end

#    args << "--with-libexpat=#{Formula["expat"].opt_prefix}" unless MacOS::CLT.installed?
    system "./configure", *args

    inreplace "doc/example.conf", 'username: "unbound"', 'username: "@@HOMEBREW-UNBOUND-USER@@"'
    system "make"
    system "make", "test"
    system "make", "install"
  end

  def post_install
    conf = etc/"unbound/unbound.conf"
    return unless conf.exist?
    return unless conf.read.include?('username: "@@HOMEBREW-UNBOUND-USER@@"')
    inreplace conf, 'username: "@@HOMEBREW-UNBOUND-USER@@"',
                    "username: \"#{ENV["USER"]}\""
  end

  service do
    run [opt_sbin/"unbound", "-d", "-c", etc/"unbound/unbound.conf"]
    working_dir HOMEBREW_PREFIX
    keep_alive true
    require_root true
  end

  test do
    system sbin/"unbound-control-setup", "-d", testpath
  end
end 

And then just install the resulting fomula:

brew install unbound@1.7.1

Enjoy!