Merge ~cgrabowski/maas:fix_dns_initialization_in_snap into maas:master

[Christian Grabowski]

ensure zone file cleanup only deletes files

ensure settings for zone file config dir are correctly encoded

[MAAS Lander (maas-lander)]

UNIT TESTS
-b fix_dns_initialization_in_snap lp:~cgrabowski/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: FAILED
LOG: http://maas-ci.internal:8080/job/maas-tester/1456/consoleText
COMMIT: 11318709ea7ded3c685138eeb105bc4db82dd653

review: Needs Fixing

[Alexsander de Souza (alexsander-souza)]

+1

review: Approve

[MAAS Lander (maas-lander)]

UNIT TESTS
-b fix_dns_initialization_in_snap lp:~cgrabowski/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: SUCCESS
COMMIT: 1e6ca51fbb5820d882dc9ec0500ef0b652e533bd

review: Approve

diff --git a/src/provisioningserver/dns/config.py b/src/provisioningserver/dns/config.py
index abb059c..ef5a166 100644
--- a/src/provisioningserver/dns/config.py
+++ b/src/provisioningserver/dns/config.py
@@ -109,6 +109,9 @@ def get_zone_file_config_dir():
     so that bind can write to the location as well
     """
     setting = os.getenv("MAAS_ZONE_FILE_CONFIG_DIR", MAAS_ZONE_FILE_DIR)
+    if isinstance(setting, bytes):
+        fsenc = sys.getfilesystemencoding()
+        setting = setting.decode(fsenc)
     return Path(setting)
 
 
@@ -238,7 +241,8 @@ def set_up_nsupdate_key():
 
 def clean_old_zone_files():
     for path in get_zone_file_config_dir().glob("zone.*"):
-        path.unlink()
+        if path.is_file():
+            path.unlink()
 
 
 def set_up_zone_file_dir():
diff --git a/src/provisioningserver/dns/tests/test_config.py b/src/provisioningserver/dns/tests/test_config.py
index 954411c..60b4c58 100644
--- a/src/provisioningserver/dns/tests/test_config.py
+++ b/src/provisioningserver/dns/tests/test_config.py
@@ -170,6 +170,19 @@ class TestHelpers(MAASTestCase):
         self.useFixture(EnvironmentVariable("MAAS_DNS_DEFAULT_CONTROLS", "0"))
         self.assertFalse(config.get_dns_default_controls())
 
+    def test_get_zone_file_config_dir_defaults_to_var_lib_bind_maas(self):
+        self.useFixture(EnvironmentVariable("MAAS_ZONE_FILE_CONFIG_DIR"))
+        self.assertEqual(
+            str(config.get_zone_file_config_dir()), "/var/lib/bind/maas"
+        )
+
+    def test_get_zone_file_config_dir_check_environ_first(self):
+        directory = self.make_dir()
+        self.useFixture(
+            EnvironmentVariable("MAAS_ZONE_FILE_CONFIG_DIR", directory)
+        )
+        self.assertEqual(str(config.get_zone_file_config_dir()), directory)
+
 
 class TestRNDCUtilities(MAASTestCase):
     def test_generate_rndc_returns_configurations(self):
@@ -307,6 +320,23 @@ class TestRNDCUtilities(MAASTestCase):
         for zonefile in zonefiles:
             self.assertRaises(FileNotFoundError, os.stat, zonefile)
 
+    def test_clean_old_zone_files_only_deletes_files(self):
+        zone_file_dir = patch_zone_file_config_path(self)
+
+        zonefiles = [
+            os.path.join(zone_file_dir, f"zone.{i}")
+            for i, _ in enumerate(range(2))
+        ]
+        for zonefile in zonefiles:
+            with open(zonefile, "w+"):
+                pass
+
+        child_dir = os.path.join(zone_file_dir, "test_dir")
+        os.mkdir(child_dir)
+
+        clean_old_zone_files()
+        self.assertIsNotNone(os.stat(child_dir))
+
     def test_rndc_config_includes_default_controls(self):
         dns_conf_dir = patch_dns_config_path(self)
         patch_dns_default_controls(self, enable=True)