Fix EOSDevice.close() leaking the Netmiko SSH session opened for file copy

changes/423.fixed

@@ -0,0 +1 @@
+Fixed `EOSDevice.close()` leaking the Netmiko SSH session opened by the file-transfer methods.

pyntc/devices/eos_device.py

@@ -250,8 +250,20 @@ def checkpoint(self, checkpoint_file):
         self.show(f"copy running-config {checkpoint_file}")
 
     def close(self):
-        """Not implemented. Just ``passes``."""
-        pass  # pylint: disable=unnecessary-pass
+        """Release the Netmiko SSH session opened by ``open``.
+
+        The eAPI transport itself is stateless HTTP and needs no teardown, but
+        ``open`` builds a real SSH session for the file-transfer paths
+        (``file_copy``, ``check_file_exists``, ``get_remote_checksum``,
+        ``remote_file_copy``). Without this, a caller holding many device objects
+        accumulates one open socket per device.
+
+        Does nothing when no SSH session was ever opened.
+        """
+        if self._connected:
+            self.native_ssh.disconnect()
+            self._connected = False
+            log.debug("Host %s: Connection closed.", self.host)
 
     def config(self, commands):
         """Send configuration commands to a device.

pyntc/devices/eos_ssh_device.py

@@ -184,17 +184,6 @@ def open(self):
 
         log.debug("Host %s: Connection to device was opened successfully.", self.host)
 
-    def close(self):
-        """Disconnect from the device.
-
-        Note this differs from ``EOSDevice.close``, which is a no-op because eAPI is
-        stateless. An SSH session holds a real socket that should be released.
-        """
-        if self._connected:
-            self.native.disconnect()
-            self._connected = False
-            log.debug("Host %s: Connection closed.", self.host)
-
     def show(self, commands, raw_text=False):
         """Send show command(s) to the device.
 

tests/unit/test_devices/test_eos_device.py

@@ -469,6 +469,50 @@ def test_init_pass_port_and_timeout(mock_eos_connect):
     )
 
 
+def test_close_disconnects_netmiko_session(eos_device):
+    # open() creates a real SSH session for the file-transfer paths; close() has to
+    # release it or long-lived callers leak a socket per device.
+    eos_device.native_ssh = mock.MagicMock()
+    eos_device._connected = True
+
+    eos_device.close()
+
+    eos_device.native_ssh.disconnect.assert_called_once()
+    assert eos_device._connected is False
+
+
+def test_close_is_noop_when_never_opened(eos_device):
+    # native_ssh is only assigned inside open(), so close() must not reach for it
+    # on a device that has only ever spoken eAPI.
+    assert not hasattr(eos_device, "native_ssh")
+
+    eos_device.close()
+
+    assert eos_device._connected is False
+
+
+def test_close_is_idempotent(eos_device):
+    eos_device.native_ssh = mock.MagicMock()
+    eos_device._connected = True
+
+    eos_device.close()
+    eos_device.close()
+
+    eos_device.native_ssh.disconnect.assert_called_once()
+
+
+@mock.patch("pyntc.devices.eos_device.ConnectHandler")
+def test_close_does_not_strand_the_device(mock_connect_handler, eos_device):
+    # Closing must stay safe for a reusable object: every SSH-backed method calls
+    # open() first, and open() has to rebuild the session a previous close() tore down.
+    eos_device.open()
+    eos_device.close()
+    eos_device.open()
+
+    assert mock_connect_handler.call_count == 2
+    assert eos_device._connected is True
+
+
 class EOSDeviceMockedTestCase(unittest.TestCase):
     """Base test case wiring a mocked ``pyeapi`` node onto an ``EOSDevice``."""