rust ovs: Raise DependencyError is NM-ovs plugin not installed

Also fix the systemd `start-limit-hit` when we restart too often during
test. Sleep 2 seconds after daemon restarted.

Signed-off-by: Gris Ge <fge@redhat.com>

rust/src/lib/error.rs

@@ -8,6 +8,7 @@ pub enum ErrorKind {
     NotImplementedError,
     NotSupportedError,
     KernelIntegerRoundedError,
+    DependencyError,
 }
 
 impl std::fmt::Display for ErrorKind {

rust/src/lib/nm/error.rs

@@ -3,11 +3,23 @@ use nm_dbus::NmError;
 use crate::{ErrorKind, NmstateError};
 
 pub(crate) fn nm_error_to_nmstate(nm_error: NmError) -> NmstateError {
-    NmstateError::new(
-        ErrorKind::Bug,
-        format!(
-            "{}: {} dbus: {:?}",
-            nm_error.kind, nm_error.msg, nm_error.dbus_error
-        ),
-    )
+    if nm_error
+        .to_string()
+        .contains("NetworkManager plugin for 'ovs-bridge' unavailable")
+    {
+        NmstateError::new(
+            ErrorKind::DependencyError,
+            "NetworkManager does not have OVS plugin installed for \
+            OVS modification"
+                .to_string(),
+        )
+    } else {
+        NmstateError::new(
+            ErrorKind::Bug,
+            format!(
+                "{}: {} dbus: {:?}",
+                nm_error.kind, nm_error.msg, nm_error.dbus_error
+            ),
+        )
+    }
 }

rust/src/libnm_dbus/nm_api.rs

@@ -340,6 +340,10 @@ where
             if cur_count == count - 1 {
                 return Err(e);
             } else {
+                if let Some(zbus::Error::MethodError(..)) = e.dbus_error {
+                    log::error!("{}", e);
+                    return Err(e);
+                }
                 log::info!("Retrying on NM dbus failure: {}", e);
                 std::thread::sleep(std::time::Duration::from_millis(
                     interval_ms,

rust/src/python/libnmstate/clib_wrapper.py

@@ -16,14 +16,15 @@ from ctypes import c_int, c_char_p, c_uint32, POINTER, byref, cdll
 import json
 
 from .error import (
+    NmstateDependencyError,
     NmstateError,
-    NmstateVerificationError,
-    NmstateValueError,
     NmstateInternalError,
-    NmstatePluginError,
-    NmstateNotImplementedError,
     NmstateKernelIntegerRoundedError,
+    NmstateNotImplementedError,
     NmstateNotSupportedError,
+    NmstatePluginError,
+    NmstateValueError,
+    NmstateVerificationError,
 )
 
 lib = cdll.LoadLibrary("libnmstate.so.2")
@@ -216,6 +217,8 @@ def map_error(err_kind, err_msg):
     elif err_kind == "KernelIntegerRoundedError":
         return NmstateKernelIntegerRoundedError(err_msg)
     elif err_kind == "NotSupportedError":
-        return NmstateNotSupportedError(err_msg);
+        return NmstateNotSupportedError(err_msg)
+    elif err_kind == "DependencyError":
+        return NmstateDependencyError(err_msg)
     else:
         return NmstateError(f"{err_kind}: {err_msg}")

tests/integration/testlib/nmplugin.py

@@ -19,6 +19,7 @@
 
 from contextlib import contextmanager
 from subprocess import CalledProcessError
+from time import sleep
 
 from . import cmdlib
 
@@ -55,9 +56,18 @@ def mount_devnull_to_path(lib_path):
 
 @contextmanager
 def nm_service_restart():
+    # If we restart too often, systemd will not start NetworkManager due to
+    # 'start-limit-hit'. Resetting failure count will helps here.
+    cmdlib.exec_cmd(
+        "systemctl reset-failed NetworkManager.service".split(), check=False
+    )
     systemctl_restart_nm_cmd = ("systemctl", "restart", "NetworkManager")
     cmdlib.exec_cmd(systemctl_restart_nm_cmd, check=True)
+    # Wait 2 seconds for NetworkManager to start.
+    sleep(2)
     try:
         yield
     finally:
         cmdlib.exec_cmd(systemctl_restart_nm_cmd, check=True)
+        # Wait 2 seconds for NetworkManager to start.
+        sleep(2)