lorax: Add --skip-branding cmdline argument

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

Resolves: rhbz#1826479

docs/lorax.rst

@@ -54,6 +54,29 @@ 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.
+
+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

@@ -186,7 +186,8 @@ class Lorax(BaseLoraxClass):
             add_arch_templates=None,
             add_arch_template_vars=None,
             verify=True,
-            user_dracut_args=None):
+            user_dracut_args=None,
+            skip_branding=False):
 
         assert self._configured
 
@@ -266,7 +267,8 @@ 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

@@ -107,6 +107,8 @@ def lorax_parser(dracut_default=""):
                           help="Size of root filesystem in GiB. Defaults to 3.")
     optional.add_argument("--noverifyssl", action="store_true", default=False,
                           help="Do not verify SSL certificates")
+    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")

src/pylorax/treebuilder.py

@@ -72,7 +72,8 @@ 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()
@@ -88,8 +89,18 @@ 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
+        The *best* way to control this is to have a single package in the repo provide 'system-release'
+        When there are more than 1 package it will:
+        - Make a list of the available packages
+        - 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

@@ -192,7 +192,8 @@ def main():
               add_arch_templates=opts.add_arch_templates,
               add_arch_template_vars=parsed_add_arch_template_vars,
               remove_temp=True, verify=opts.verify,
-              user_dracut_args=opts.dracut_args)
+              user_dracut_args=opts.dracut_args,
+              skip_branding=opts.skip_branding)
 
     # Release the lock on the tempdir
     os.close(dir_fd)