DataSourceSmartOS: list() should always return a list

If customer_metadata has no keys, the KEYS request returns an empty
string. Callers of the list() method expect a list to be returned and
will give a stack trace if this expectation is not met.

LP: #1763480

2 files changed, 27 insertions, 5 deletions

diff --git a/cloudinit/sources/DataSourceSmartOS.py b/cloudinit/sources/DataSourceSmartOS.py
index c8998b40..d4386fec 100644
--- a/cloudinit/sources/DataSourceSmartOS.py
+++ b/cloudinit/sources/DataSourceSmartOS.py
@@ -455,9 +455,9 @@ class JoyentMetadataClient(object):
 
     def list(self):
         result = self.request(rtype='KEYS')
-        if result:
-            result = result.split('\n')
-        return result
+        if not result:
+            return []
+        return result.split('\n')
 
     def put(self, key, val):
         param = b' '.join([base64.b64encode(i.encode())
diff --git a/tests/unittests/test_datasource/test_smartos.py b/tests/unittests/test_datasource/test_smartos.py
index 2bea7a17..6fd431f9 100644
--- a/tests/unittests/test_datasource/test_smartos.py
+++ b/tests/unittests/test_datasource/test_smartos.py
@@ -319,6 +319,12 @@ MOCK_RETURNS = {
 
 DMI_DATA_RETURN = 'smartdc'
 
+# Useful for calculating the length of a frame body.  A SUCCESS body will be
+# followed by more characters or be one character less if SUCCESS with no
+# payload.  See Section 4.3 of https://eng.joyent.com/mdata/protocol.html.
+SUCCESS_LEN = len('0123abcd SUCCESS ')
+NOTFOUND_LEN = len('0123abcd NOTFOUND')
+
 
 class PsuedoJoyentClient(object):
     def __init__(self, data=None):
@@ -651,7 +657,7 @@ class TestJoyentMetadataClient(FilesystemMockingTestCase):
         self.response_parts = {
             'command': 'SUCCESS',
             'crc': 'b5a9ff00',
-            'length': 17 + len(b64e(self.metadata_value)),
+            'length': SUCCESS_LEN + len(b64e(self.metadata_value)),
             'payload': b64e(self.metadata_value),
             'request_id': '{0:08x}'.format(self.request_id),
         }
@@ -787,7 +793,7 @@ class TestJoyentMetadataClient(FilesystemMockingTestCase):
     def test_get_metadata_returns_None_if_value_not_found(self):
         self.response_parts['payload'] = ''
         self.response_parts['command'] = 'NOTFOUND'
-        self.response_parts['length'] = 17
+        self.response_parts['length'] = NOTFOUND_LEN
         client = self._get_client()
         client._checksum = lambda _: self.response_parts['crc']
         self.assertIsNone(client.get('some_key'))
@@ -838,6 +844,22 @@ class TestJoyentMetadataClient(FilesystemMockingTestCase):
         client.open_transport()
         self.assertTrue(reader.emptied)
 
+    def test_list_metadata_returns_list(self):
+        parts = ['foo', 'bar']
+        value = b64e('\n'.join(parts))
+        self.response_parts['payload'] = value
+        self.response_parts['crc'] = '40873553'
+        self.response_parts['length'] = SUCCESS_LEN + len(value)
+        client = self._get_client()
+        self.assertEqual(client.list(), parts)
+
+    def test_list_metadata_returns_empty_list_if_no_customer_metadata(self):
+        del self.response_parts['payload']
+        self.response_parts['length'] = SUCCESS_LEN - 1
+        self.response_parts['crc'] = '14e563ba'
+        client = self._get_client()
+        self.assertEqual(client.list(), [])
+
 
 class TestNetworkConversion(TestCase):
     def test_convert_simple(self):