api: fix unattended-upgrades for pkg not installed

When unattended-upgrades is uninstalled in the machine,
we display an error on the api endpoint that doesn't directly
tell the user that the package is not installed. We are updating
the logic to properly tell the user that the package is not
installed.

Fixes: #2807

features/api_unattended_upgrades.feature

@@ -196,6 +196,12 @@ Feature: api.u.unattended_upgrades.status.v1
           "vim"
         ]
         """
+        When I run `apt remove unattended-upgrades -y` with sudo
+        And I run `pro api u.unattended_upgrades.status.v1` as non-root
+        Then stdout matches regexp:
+        """
+        {"_schema_version": "v1", "data": {"attributes": {"apt_periodic_job_enabled": false, "package_lists_refresh_frequency_days": 0, "systemd_apt_timer_enabled": false, "unattended_upgrades_allowed_origins": \[\], "unattended_upgrades_disabled_reason": {"code": "unattended-upgrades-uninstalled", "msg": "unattended-upgrades packages is not installed"}, "unattended_upgrades_frequency_days": 0, "unattended_upgrades_last_run": null, "unattended_upgrades_running": false}, "meta": {"environment_vars": \[\]}, "type": "UnattendedUpgradesStatus"}, "errors": \[\], "result": "success", "version": ".*", "warnings": \[\]}
+        """
 
         Examples: ubuntu release
            | release | extra_field                               |

uaclient/api/tests/test_api_u_unattended_upgrades_status_v1.py

@@ -8,6 +8,7 @@
     UNATTENDED_UPGRADES_CFG_LIST_VALUE_EMPTY,
     UNATTENDED_UPGRADES_CFG_VALUE_TURNED_OFF,
     UNATTENDED_UPGRADES_SYSTEMD_JOB_DISABLED,
+    UNATTENDED_UPGRADES_UNINSTALLED,
 )
 
 M_PATH = "uaclient.api.u.unattended_upgrades.status.v1"
@@ -92,6 +93,7 @@ def test_unattended_upgrades_last_run_when_file_not_present(
 
 
 class TestUnattendedUpgradesStatusV1:
+    @mock.patch("uaclient.apt.is_installed", return_value=True)
     @mock.patch(M_PATH + ".get_apt_config_keys")
     @mock.patch(M_PATH + ".get_apt_config_values")
     @mock.patch(M_PATH + "._is_unattended_upgrades_running")
@@ -104,6 +106,7 @@ def test_unattended_upgrades_status_v1(
         m_is_running,
         m_apt_cfg_values,
         m_apt_cfg_keys,
+        _m_apt_is_installed,
         FakeConfig,
     ):
         expected_datetime = datetime.datetime(2023, 2, 23, 15, 0, 0, 102490)
@@ -154,3 +157,28 @@ def test_unattended_upgrades_status_v1(
         assert m_apt_job_status.call_count == 1
         assert m_apt_cfg_values.call_count == 1
         assert m_last_run.call_count == 1
+        assert _m_apt_is_installed.call_count == 1
+
+    @mock.patch("uaclient.apt.is_installed", return_value=False)
+    def test_unattended_upgrades_status_v1_when_pkg_not_installed(
+        self,
+        _m_apt_is_installed,
+        FakeConfig,
+    ):
+        actual_return = api._status(FakeConfig())
+        assert False is actual_return.apt_periodic_job_enabled
+        assert False is actual_return.systemd_apt_timer_enabled
+        assert 0 == actual_return.package_lists_refresh_frequency_days
+        assert 0 == actual_return.unattended_upgrades_frequency_days
+        assert [] == actual_return.unattended_upgrades_allowed_origins
+        assert False is actual_return.unattended_upgrades_running
+        assert None is actual_return.unattended_upgrades_last_run
+        assert (
+            api.UnattendedUpgradesDisabledReason(
+                msg=UNATTENDED_UPGRADES_UNINSTALLED.msg,
+                code=UNATTENDED_UPGRADES_UNINSTALLED.name,
+            )
+            == actual_return.unattended_upgrades_disabled_reason
+        )
+
+        assert _m_apt_is_installed.call_count == 1

uaclient/api/u/unattended_upgrades/status/v1.py

@@ -2,7 +2,7 @@
 import os
 from typing import Dict, List, Optional, Tuple, Union
 
-from uaclient import exceptions, messages, system
+from uaclient import apt, exceptions, messages, system
 from uaclient.api.api import APIEndpoint
 from uaclient.api.data_types import AdditionalInfo
 from uaclient.api.exceptions import UnattendedUpgradesError
@@ -15,6 +15,7 @@
     Field,
     IntDataValue,
     StringDataValue,
+    data_list,
 )
 
 UNATTENDED_UPGRADES_CONFIG_KEYS = [
@@ -42,18 +43,22 @@ class UnattendedUpgradesStatusResult(DataObject, AdditionalInfo):
     fields = [
         Field("systemd_apt_timer_enabled", BoolDataValue),
         Field("apt_periodic_job_enabled", BoolDataValue),
-        Field("package_lists_refresh_frequency_days", IntDataValue),
+        Field(
+            "package_lists_refresh_frequency_days",
+            IntDataValue,
+        ),
         Field("unattended_upgrades_frequency_days", IntDataValue),
-        Field("unattended_upgrades_allowed_origins", StringDataValue),
+        Field(
+            "unattended_upgrades_allowed_origins",
+            data_list(StringDataValue),
+        ),
         Field("unattended_upgrades_running", BoolDataValue),
         Field(
             "unattended_upgrades_disabled_reason",
             UnattendedUpgradesDisabledReason,
             required=False,
         ),
-        Field(
-            "unattended_upgrades_last_run", DatetimeDataValue, required=False
-        ),
+        Field("unattended_upgrades_last_run", DatetimeDataValue),
     ]
 
     def __init__(
@@ -145,6 +150,21 @@ def status() -> UnattendedUpgradesStatusResult:
 
 
 def _status(cfg: UAConfig) -> UnattendedUpgradesStatusResult:
+    if not apt.is_installed("unattended-upgrades"):
+        return UnattendedUpgradesStatusResult(
+            systemd_apt_timer_enabled=False,
+            apt_periodic_job_enabled=False,
+            package_lists_refresh_frequency_days=0,
+            unattended_upgrades_frequency_days=0,
+            unattended_upgrades_allowed_origins=[],
+            unattended_upgrades_disabled_reason=UnattendedUpgradesDisabledReason(  # noqa
+                msg=messages.UNATTENDED_UPGRADES_UNINSTALLED.msg,
+                code=messages.UNATTENDED_UPGRADES_UNINSTALLED.name,
+            ),
+            unattended_upgrades_running=False,
+            unattended_upgrades_last_run=None,
+        )
+
     systemd_apt_timer_enabled = _get_apt_daily_job_status()
     unattended_upgrades_last_run = _get_unattended_upgrades_last_run()
 

uaclient/messages/__init__.py

@@ -1850,6 +1850,10 @@ def __repr__(self):
     "unattended-upgrades-cfg-value-turned-off",
     t.gettext("{cfg_name} is turned off"),
 )
+UNATTENDED_UPGRADES_UNINSTALLED = NamedMessage(
+    "unattended-upgrades-uninstalled",
+    "unattended-upgrades packages is not installed",
+)
 
 LANDSCAPE_CLIENT_NOT_INSTALLED = NamedMessage(
     "landscape-client-not-installed",