Add detection for ostree-based systems and warn users about losing ch…

…anges

On ostree-based systems, users can use dnf to customize the
environment but those changes will be lost at the next ostree-based
image update.  If you want to retain changes between ostree-updates
you need to make use of rpm-ostree right now.

Signed-off-by: David Cantrell <[email protected]>

dnf/cli/cli.py

@@ -214,6 +214,15 @@ def do_transaction(self, display=()):
  elif 'test' in self.conf.tsflags:
  logger.info(_("{prog} will only download packages, install gpg keys, and check the "
  "transaction.").format(prog=dnf.util.MAIN_PROG_UPPER))
+ if dnf.util.is_container():
+ _container_msg = _("""
+*** This system is managed with ostree. Changes to the system
+*** made with dnf will be lost with the next ostree-based update.
+*** If you do not want to lose these changes, use 'rpm-ostree'.
+""")
+ logger.info(_container_msg)
+ raise CliError(_("Operation aborted."))
+
  if self._promptWanted():
  if self.conf.assumeno or not self.output.userconfirm():
  raise CliError(_("Operation aborted."))

dnf/util.py

@@ -33,11 +33,13 @@
 import functools
 import hawkey
 import itertools
+import json
 import locale
 import logging
 import os
 import pwd
 import shutil
+import subprocess
 import sys
 import tempfile
 import time
@@ -639,3 +641,32 @@ def _is_file_pattern_present(specs):
  if subj._filename_pattern:
  return True
  return False
+
+
+def is_container():
+ """Returns true is the system is managed as an immutable container,
+ false otherwise. If msg is True, a warning message is displayed
+ for the user.
+ """
+
+ bootc = '/usr/bin/bootc'
+ ostree = '/sysroot/ostree'
+
+ if os.path.isfile(bootc) and os.access(bootc, os.X_OK):
+ p = subprocess.Popen([bootc, "status", "--json"], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+ (out, err) = p.communicate()
+
+ if p.returncode == 0:
+ # check the output of 'bootc status'
+ j = json.loads(out)
+
+ # XXX: the API from bootc status is evolving
+ status = j.get("status", "")
+ kind = j.get("kind", "")
+
+ if kind.lower() == "bootchost" and bool(status.get("isContainer", None)):
+ return True
+ elif os.path.isdir(ostree):
+ return True
+
+ return False