Copy dnf.conf to target userspace and allow a custom one

This change allows working around the fact that source and target
`dnf.conf` files might be incompatible. For example some of the proxy
configuration between RHEL7 and RHEL8.

Target system compatible configuration can be specified in
/etc/leapp/files/dnf.conf. If this file is present it is copied into
the target userspace and also applied to the target system. If it
doesn't exist, the `/etc/dnf/dnf.conf` from the source system will be
copied instead.

Errors that could be caused by incompatible/incorrect proxy
configuration now contain a hint with a remediation with the steps above
mentioned.

Jira: OAMG-6544

repos/system_upgrade/common/actors/dnfconftargetusecustom/actor.py

@@ -0,0 +1,19 @@
+from leapp.actors import Actor
+from leapp.libraries.actor import dnfconftargetusecustom
+from leapp.tags import ApplicationsPhaseTag, IPUWorkflowTag
+
+
+class DNFConfTargetUseCustom(Actor):
+    """
+    Move /etc/leapp/files/dnf.conf to /etc/dnf/dnf.conf if it exists
+
+    An actor in FactsPhase copies this file to the target userspace if present.
+    In such case we also want to use the file on the target system.
+    """
+    name = "dnf_conf_target_use_custom"
+    consumes = ()
+    produces = ()
+    tags = (ApplicationsPhaseTag, IPUWorkflowTag)
+
+    def process(self):
+        dnfconftargetusecustom.process()

repos/system_upgrade/common/actors/dnfconftargetusecustom/libraries/dnfconftargetusecustom.py

@@ -0,0 +1,15 @@
+import os
+
+from leapp.libraries.stdlib import api, CalledProcessError, run
+
+CUSTOM_DNF_CONF_PATH = "/etc/leapp/files/dnf.conf"
+
+
+def process():
+    if os.path.exists(CUSTOM_DNF_CONF_PATH):
+        try:
+            run(["mv", CUSTOM_DNF_CONF_PATH, "/etc/dnf/dnf.conf"])
+        except (CalledProcessError, OSError) as e:
+            api.current_logger().debug(
+                "Failed to move /etc/leapp/files/dnf.conf to /etc/dnf/dnf.conf: {}".format(e)
+            )

repos/system_upgrade/common/actors/dnfconftargetusecustom/tests/test_dnfconftargetusecustom.py

@@ -0,0 +1,23 @@
+import os
+
+import pytest
+
+from leapp.libraries.actor import dnfconftargetusecustom
+
+
+@pytest.mark.parametrize(
+    "exists,should_move",
+    [(False, False), (True, True)],
+)
+def test_copy_correct_dnf_conf(monkeypatch, exists, should_move):
+    monkeypatch.setattr(os.path, "exists", lambda _: exists)
+
+    run_called = [False]
+
+    def mocked_run(_):
+        run_called[0] = True
+
+    monkeypatch.setattr(dnfconftargetusecustom, 'run', mocked_run)
+
+    dnfconftargetusecustom.process()
+    assert run_called[0] == should_move

repos/system_upgrade/common/actors/dnfconfuserspacecopy/actor.py

@@ -0,0 +1,24 @@
+from leapp.actors import Actor
+from leapp.libraries.actor import dnfconfuserspacecopy
+from leapp.models import TargetUserSpacePreupgradeTasks
+from leapp.tags import FactsPhaseTag, IPUWorkflowTag
+
+
+class DNFConfUserspaceCopy(Actor):
+    """
+    Copy dnf.conf to target userspace
+
+    Copies /etc/leapp/files/dnf.conf to target userspace. If it isn't available
+    /etc/dnf/dnf.conf is copied instead. This allows specifying a different
+    config for the target userspace, which might be required if the source
+    system configuration file isn't compatible with the target one. One such
+    example is incompatible proxy configuration between RHEL7 and RHEL8 DNF
+    versions.
+    """
+    name = "dnf_conf_userspace_copy"
+    consumes = ()
+    produces = (TargetUserSpacePreupgradeTasks,)
+    tags = (FactsPhaseTag, IPUWorkflowTag)
+
+    def process(self):
+        dnfconfuserspacecopy.process()

repos/system_upgrade/common/actors/dnfconfuserspacecopy/libraries/dnfconfuserspacecopy.py

@@ -0,0 +1,19 @@
+import os
+
+from leapp.libraries.stdlib import api
+from leapp.models import CopyFile, TargetUserSpacePreupgradeTasks
+
+
+def process():
+    src = "/etc/dnf/dnf.conf"
+    if os.path.exists("/etc/leapp/files/dnf.conf"):
+        src = "/etc/leapp/files/dnf.conf"
+
+    api.current_logger().debug(
+        "Copying dnf.conf at {} to the target userspace".format(src)
+    )
+    api.produce(
+        TargetUserSpacePreupgradeTasks(
+            copy_files=[CopyFile(src=src, dst="/etc/dnf/dnf.conf")]
+        )
+    )

repos/system_upgrade/common/actors/dnfconfuserspacecopy/tests/test_dnfconfuserspacecopy.py

@@ -0,0 +1,26 @@
+import os
+
+import pytest
+
+from leapp.libraries.actor import dnfconfuserspacecopy
+from leapp.libraries.common.testutils import logger_mocked, produce_mocked
+
+
+@pytest.mark.parametrize(
+    "userspace_conf_exists,expected",
+    [(False, "/etc/dnf/dnf.conf"), (True, "/etc/leapp/files/dnf.conf")],
+)
+def test_copy_correct_dnf_conf(monkeypatch, userspace_conf_exists, expected):
+    monkeypatch.setattr(os.path, "exists", lambda _: userspace_conf_exists)
+
+    mocked_produce = produce_mocked()
+    monkeypatch.setattr(dnfconfuserspacecopy.api, 'produce', mocked_produce)
+    monkeypatch.setattr(dnfconfuserspacecopy.api, 'current_logger', logger_mocked())
+
+    dnfconfuserspacecopy.process()
+
+    assert mocked_produce.called == 1
+    assert len(mocked_produce.model_instances) == 1
+    assert len(mocked_produce.model_instances[0].copy_files) == 1
+    assert mocked_produce.model_instances[0].copy_files[0].src == expected
+    assert mocked_produce.model_instances[0].copy_files[0].dst == "/etc/dnf/dnf.conf"

repos/system_upgrade/common/actors/targetuserspacecreator/libraries/userspacegen.py

@@ -269,15 +269,25 @@ def prepare_target_userspace(context, userspace_dir, enabled_repos, packages):
             # failed since leapp does not support updates behind proxy yet.
             for manager_info in api.consume(PkgManagerInfo):
                 if manager_info.configured_proxies:
-                    details['details'] = ("DNF failed to install userspace packages, likely due to the proxy "
-                                          "configuration detected in the YUM/DNF configuration file.")
+                    details['details'] = (
+                        "DNF failed to install userspace packages, likely due to the proxy "
+                        "configuration detected in the YUM/DNF configuration file. "
+                        "Make sure the proxy is properly configured in /etc/dnf/dnf.conf. "
+                        "It's also possible the proxy settings in the DNF configuration file are "
+                        "incompatible with the target system. A compatible configuration can be "
+                        "placed in /etc/leapp/files/dnf.conf which, if present, will be used during "
+                        "the upgrade instead of /etc/dnf/dnf.conf. "
+                        "In such case the configuration will also be applied to the target system."
+                    )
 
             # Similarly if a proxy was set specifically for one of the repositories.
             for repo_facts in api.consume(RepositoriesFacts):
                 for repo_file in repo_facts.repositories:
                     if any(repo_data.proxy and repo_data.enabled for repo_data in repo_file.data):
-                        details['details'] = ("DNF failed to install userspace packages, likely due to the proxy "
-                                              "configuration detected in a repository configuration file.")
+                        details['details'] = (
+                            "DNF failed to install userspace packages, likely due to the proxy "
+                            "configuration detected in a repository configuration file."
+                        )
 
             raise StopActorExecutionError(message=message, details=details)
 

repos/system_upgrade/common/libraries/dnfplugin.py

@@ -178,8 +178,28 @@ def _handle_transaction_err_msg(stage, xfs_info, err, is_container=False):
         return  # not needed actually as the above function raises error, but for visibility
     NO_SPACE_STR = 'more space needed on the'
     message = 'DNF execution failed with non zero exit code.'
-    details = {'STDOUT': err.stdout, 'STDERR': err.stderr}
     if NO_SPACE_STR not in err.stderr:
+        # if there was a problem reaching repos and proxy is configured in DNF/YUM configs, the
+        # proxy is likely the problem.
+        # NOTE(mmatuska): We can't consistently detect there was a problem reaching some repos,
+        # because it isn't clear what are all the possible DNF error messages we can encounter,
+        # such as: "Failed to synchronize cache for repo ..." or "Errors during downloading
+        # metadata for # repository" or "No more mirrors to try - All mirrors were already tried
+        # without success"
+        # NOTE(mmatuska): We could check PkgManagerInfo to detect if proxy is indeed configured,
+        # however it would be pretty ugly to pass it all the way down here
+        proxy_hint = (
+            "If there was a problem reaching repositories (see stderr output) and proxy is "
+            "configured in the YUM/DNF configuration file, the proxy configuration is likely "
+            "causing this error. "
+            "Make sure the proxy is properly configured in /etc/dnf/dnf.conf. "
+            "It's also possible the proxy settings in the DNF configuration file are "
+            "incompatible with the target system. A compatible configuration can be "
+            "placed in /etc/leapp/files/dnf.conf which, if present, will be used during "
+            "the upgrade instead of /etc/dnf/dnf.conf. "
+            "In such case the configuration will also be applied to the target system."
+        )
+        details = {'STDOUT': err.stdout, 'STDERR': err.stderr, 'hint': proxy_hint}
         raise StopActorExecutionError(message=message, details=details)
 
     # Disk Requirements: