payload/rpm-ostree: Include program output in exception

The rpm-ostree container deployment path can fail for many reasons
from networking to details in mount setup.

What we really want is a proper API with progress out of bootc/ostree;
I will work on that at some point.

In the meantime though, just capture stderr on failure and include
it in the payload installation error so people don't have to
dig into `program.log` which is very obscure.

Signed-off-by: Colin Walters <[email protected]>

pyanaconda/modules/payloads/payload/rpm_ostree/installation.py

@@ -26,7 +26,7 @@
 from pyanaconda.core.glib import GError, Variant, create_new_context, format_size_full
 from pyanaconda.core.i18n import _
 from pyanaconda.core.path import make_directories, set_system_root
-from pyanaconda.core.util import execWithRedirect
+from pyanaconda.core.util import execWithRedirect, execProgram
 from pyanaconda.modules.common.constants.objects import BOOTLOADER, DEVICE_TREE
 from pyanaconda.modules.common.constants.services import LOCALIZATION, STORAGE
 from pyanaconda.modules.common.errors.installation import (
@@ -50,11 +50,12 @@ def safe_exec_with_redirect(cmd, argv, successful_return_codes=(0,), **kwargs):
 
     :raise: PayloadInstallationError if the call fails for any reason
     """
-    rc = execWithRedirect(cmd, argv, **kwargs)
+    rc, output = execProgram([cmd] + argv, **kwargs)
 
     if rc not in successful_return_codes:
         raise PayloadInstallationError(
-            "The command '{}' exited with the code {}.".format(" ".join([cmd] + argv), rc)
+            "The command '{}' exited with the code {}:\n{}".format(" ".join([cmd] + argv), rc,
+            output)
         )