cephadm: Fix get_cluster_count when data_dir is missing

It is possible for cephadm, if it fails to create a cluster, to direct
the user to delete the cluster even though the data_dir has not yet been
created. Running that command would fail during the cluster count check.

Signed-off-by: James Oakley <[email protected]>

Author: jimfunk

src/cephadm/cephadm.py

@@ -3960,7 +3960,9 @@ def command_zap_osds(ctx: CephadmContext) -> None:
 
 
 def get_ceph_cluster_count(ctx: CephadmContext) -> int:
-    return len([c for c in os.listdir(ctx.data_dir) if is_fsid(c)])
+    if os.path.isdir(ctx.data_dir):
+        return len([c for c in os.listdir(ctx.data_dir) if is_fsid(c)])
+    return 0
 
 
 def command_rm_cluster(ctx: CephadmContext) -> None:

src/cephadm/tests/test_cephadm.py

@@ -1501,8 +1501,14 @@ def test_extract_uid_gid_fail(self, _call):
     ])
     def test_get_ceph_cluster_count(self, test_input, expected):
         ctx = _cephadm.CephadmContext()
-        with mock.patch('os.listdir', return_value=test_input):
-            assert _cephadm.get_ceph_cluster_count(ctx) == expected
+        with mock.patch('os.path.isdir', return_value=True):
+            with mock.patch('os.listdir', return_value=test_input):
+                assert _cephadm.get_ceph_cluster_count(ctx) == expected
+
+    def test_get_ceph_cluster_count_missing_datadir(self):
+        ctx = _cephadm.CephadmContext()
+        with mock.patch('os.path.isdir', return_value=False):
+            assert _cephadm.get_ceph_cluster_count(ctx) == 0
 
     def test_set_image_minimize_config(self):
         def throw_cmd(cmd):