lorax: Add --skip-branding cmdline argument

Also document how branding currently works. See docs/lorax.rst

Resolves: rhbz#1826479

docs/lorax.rst

@@ -54,6 +54,40 @@ Under ``./results/`` will be the release tree files: .discinfo, .treeinfo, every
 goes onto the boot.iso, the pxeboot directory, and the boot.iso under ``./images/``.
 
 
+Branding
+--------
+
+By default lorax will search for the first package that provides ``system-release``
+that doesn't start with ``generic-`` and will install it. It then selects a
+corresponding logo package by using the first part of the system-release package and
+appending ``-logos`` to it. eg. fedora-release and fedora-logos.
+
+Variants
+~~~~~~~~
+
+If a ``variant`` is passed to lorax it will select a ``system-release`` package that
+ends with the variant name. eg. Passing ``--variant workstation`` will select the
+``fedora-release-workstation`` package if it exists. It will select a logo package
+the same way it does for non-variants. eg. ``fedora-logos``.
+
+If there is no package ending with the variant name it will fall back to using the
+first non-generic package providing ``system-release``.
+
+Custom Branding
+~~~~~~~~~~~~~~~
+
+If ``--skip-branding`` is passed to lorax it will skip selecting the
+``system-release``, and logos packages and leave it up to the user to pass any
+branding related packages to lorax using ``--installpkgs``. When using
+``skip-branding`` you must make sure that you provide all of the expected files,
+otherwise Anaconda may not work as expected. See the contents of ``fedora-release``
+and ``fedora-logos`` for examples of what to include.
+
+Note that this does not prevent something else in the dependency tree from
+causing these packages to be included. Using ``--excludepkgs`` may help if they
+are unexpectedly included.
+
+
 Running inside of mock
 ----------------------
 

src/pylorax/__init__.py

@@ -183,7 +183,8 @@ class Lorax(BaseLoraxClass):
             add_arch_template_vars=None,
             verify=True,
             user_dracut_args=None,
-            squashfs_only=False):
+            squashfs_only=False,
+            skip_branding=False):
 
         assert self._configured
 
@@ -263,7 +264,8 @@ class Lorax(BaseLoraxClass):
                             installpkgs=installpkgs,
                             excludepkgs=excludepkgs,
                             add_templates=add_templates,
-                            add_template_vars=add_template_vars)
+                            add_template_vars=add_template_vars,
+                            skip_branding=skip_branding)
 
         logger.info("installing runtime packages")
         rb.install()

src/pylorax/cmdline.py

@@ -111,6 +111,8 @@ def lorax_parser(dracut_default=""):
                           help="Enable a DNF plugin by name/glob, or * to enable all of them.")
     optional.add_argument("--squashfs-only", action="store_true", default=False,
                           help="Use a plain squashfs filesystem for the runtime.")
+    optional.add_argument("--skip-branding", action="store_true", default=False,
+                          help="Disable automatic branding package selection. Use --installpkgs to add custom branding.")
 
     # dracut arguments
     dracut_group = parser.add_argument_group("dracut arguments: (default: %s)" % dracut_default)

src/pylorax/treebuilder.py

@@ -71,7 +71,8 @@ class RuntimeBuilder(object):
     def __init__(self, product, arch, dbo, templatedir=None,
                  installpkgs=None, excludepkgs=None,
                  add_templates=None,
-                 add_template_vars=None):
+                 add_template_vars=None,
+                 skip_branding=False):
         root = dbo.conf.installroot
         # use a copy of product so we can modify it locally
         product = product.copy()
@@ -87,6 +88,7 @@ class RuntimeBuilder(object):
         self._excludepkgs = excludepkgs or []
         self._runner.defaults = self.vars
         self.dbo.reset()
+        self._skip_branding = skip_branding
 
     def _install_branding(self):
         """Select the branding from the available 'system-release' packages
@@ -96,6 +98,9 @@ class RuntimeBuilder(object):
         - If variant is set look for a package ending with lower(variant) and use that
         - If there are one or more non-generic packages, use the first one after sorting
         """
+        if self._skip_branding:
+            return
+
         release = None
         q = self.dbo.sack.query()
         a = q.available()

src/sbin/lorax

@@ -213,7 +213,8 @@ def main():
               add_arch_template_vars=parsed_add_arch_template_vars,
               remove_temp=True, verify=opts.verify,
               user_dracut_args=user_dracut_args,
-              squashfs_only=opts.squashfs_only)
+              squashfs_only=opts.squashfs_only,
+              skip_branding=opts.skip_branding)
 
     # Release the lock on the tempdir
     os.close(dir_fd)

tests/pylorax/test_treebuilder.py

@@ -62,7 +62,7 @@ def makeFakeRPM(repo_dir, name, epoch, version, release, files=None, provides=No
 
 
 class InstallBrandingTestCase(unittest.TestCase):
-    def install_branding(self, repo_dir, variant=None):
+    def install_branding(self, repo_dir, variant=None, skip_branding=False):
         """Run the _install_branding and return the names of the installed packages"""
         with tempfile.TemporaryDirectory(prefix="lorax.test.") as root_dir:
             dbo = get_dnf_base_object(root_dir, ["file://"+repo_dir], enablerepos=[], disablerepos=[])
@@ -71,7 +71,7 @@ class InstallBrandingTestCase(unittest.TestCase):
             product = DataHolder(name="Fedora", version="33", release="33",
                                  variant=variant, bugurl="http://none", isfinal=True)
             arch = ArchData(os.uname().machine)
-            rb = RuntimeBuilder(product, arch, dbo)
+            rb = RuntimeBuilder(product, arch, dbo, skip_branding=skip_branding)
             rb._install_branding()
             dbo.resolve()
             self.assertTrue(dbo.transaction is not None)
@@ -134,3 +134,13 @@ class InstallBrandingTestCase(unittest.TestCase):
             # Test with a variant set, but not available
             pkgs = self.install_branding(repo_dir, variant="server")
             self.assertEqual(pkgs, ["fedora-logos", "fedora-release"])
+
+    def test_skip_branding(self):
+        """Test disabled branding"""
+        with tempfile.TemporaryDirectory(prefix="lorax.test.repo.") as repo_dir:
+            makeFakeRPM(repo_dir, "fedora-release", 0, "33", "1", ["/etc/system-release"], ["system-release"])
+            makeFakeRPM(repo_dir, "fedora-logos", 0, "33", "1")
+            os.system("createrepo_c " + repo_dir)
+
+            pkgs = self.install_branding(repo_dir, skip_branding=True)
+            self.assertEqual(pkgs, [])