Add dbus service to support restart and kill process

host_modules/systemd_service.py

@@ -0,0 +1,50 @@
+"""Systemd service handler"""
+
+from host_modules import host_service
+import subprocess
+
+MOD_NAME = 'systemd'
+ALLOWED_SERVICES = ['snmp', 'swss', 'dhcp_relay', 'radv', 'restapi', 'lldp', 'sshd', 'pmon', 'rsyslog', 'telemetry']
+EXIT_FAILURE = 1
+
+
+class SystemdService(host_service.HostModule):
+    """
+    DBus endpoint that executes the service command
+    """
+    @host_service.method(host_service.bus_name(MOD_NAME), in_signature='s', out_signature='is')
+    def restart_service(self, service):
+        if not service:
+            return EXIT_FAILURE, "Dbus restart_service called with no service specified"
+        if service not in ALLOWED_SERVICES:
+            return EXIT_FAILURE, "Dbus does not support {} service restart".format(service)
+
+        cmd = ['/usr/bin/systemctl', 'reset-failed', service]
+        result = subprocess.run(cmd, shell=False, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        if result.returncode:
+            possible_expected_error = "Failed to reset failed state"
+            msg = result.stderr.decode()
+            if possible_expected_error not in msg:
+                return result.returncode, msg  # Throw error only if unexpected error
+
+        msg = ''
+        cmd = ['/usr/bin/systemctl', 'restart', service]
+        result = subprocess.run(cmd, shell=False, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        if result.returncode:
+            msg = result.stderr.decode()
+
+        return result.returncode, msg
+
+    @host_service.method(host_service.bus_name(MOD_NAME), in_signature='s', out_signature='is')
+    def stop_service(self, service):
+        if not service:
+            return EXIT_FAILURE, "Dbus stop_service called with no service specified"
+        if service not in ALLOWED_SERVICES:
+            return EXIT_FAILURE, "Dbus does not support {} service management".format(service)
+
+        cmd = ['/usr/bin/systemctl', 'stop', service]
+        result = subprocess.run(cmd, shell=False, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        msg = ''
+        if result.returncode:
+            msg = result.stderr.decode()
+        return result.returncode, msg

scripts/sonic-host-server

@@ -12,7 +12,7 @@ import dbus.service
 import dbus.mainloop.glib
 
 from gi.repository import GObject
-from host_modules import config_engine, gcu, host_service, showtech
+from host_modules import config_engine, gcu, host_service, showtech, systemd_service
 
 
 def register_dbus():
@@ -21,7 +21,8 @@ def register_dbus():
             'config': config_engine.Config('config'),
             'gcu': gcu.GCU('gcu'),
             'host_service': host_service.HostService('host_service'),
-            'showtech': showtech.Showtech('showtech')
+            'showtech': showtech.Showtech('showtech'),
+            'systemd': systemd_service.SystemdService('systemd')
             }
     for mod_name, handler_class in mod_dict.items():
         handlers[mod_name] = handler_class

tests/host_modules/systemd_service_test.py

@@ -0,0 +1,86 @@
+import sys
+import os
+import pytest
+from unittest import mock
+from host_modules import systemd_service
+
+class TestSystemdService(object):
+    @mock.patch("dbus.SystemBus")
+    @mock.patch("dbus.service.BusName")
+    @mock.patch("dbus.service.Object.__init__")
+    def test_service_restart_valid(self, MockInit, MockBusName, MockSystemBus):
+        with mock.patch("subprocess.run") as mock_run:
+            res_mock = mock.Mock()
+            test_ret = 0
+            test_msg = b"Succeeded"
+            attrs = {"returncode": test_ret, "stderr": test_msg}
+            res_mock.configure_mock(**attrs)
+            mock_run.return_value = res_mock
+            service = "snmp"
+            systemd_service_stub = systemd_service.SystemdService(systemd_service.MOD_NAME)
+            ret, msg = systemd_service_stub.restart_service(service)
+            call_args = mock_run.call_args[0][0]
+            assert service in call_args
+            assert "/usr/bin/systemctl" in call_args
+            assert ret == test_ret, "Return value is wrong"
+            assert msg == "", "Return message is wrong"
+
+    @mock.patch("dbus.SystemBus")
+    @mock.patch("dbus.service.BusName")
+    @mock.patch("dbus.service.Object.__init__")
+    def test_service_restart_invalid(self, MockInit, MockBusName, MockSystemBus):
+        systemd_service_stub = systemd_service.SystemdService(systemd_service.MOD_NAME)
+        service = "unsupported_service"
+        ret, msg = systemd_service_stub.restart_service(service)
+        assert ret == 1
+        assert "Dbus does not support" in msg
+
+    @mock.patch("dbus.SystemBus")
+    @mock.patch("dbus.service.BusName")
+    @mock.patch("dbus.service.Object.__init__")
+    def test_service_restart_empty(self, MockInit, MockBusName, MockSystemBus):
+        service = ""
+        systemd_service_stub = systemd_service.SystemdService(systemd_service.MOD_NAME)
+        ret, msg = systemd_service_stub.restart_service(service)
+        assert ret == 1
+        assert "restart_service called with no service specified" in msg
+
+    @mock.patch("dbus.SystemBus")
+    @mock.patch("dbus.service.BusName")
+    @mock.patch("dbus.service.Object.__init__")
+    def test_service_stop_valid(self, MockInit, MockBusName, MockSystemBus):
+        with mock.patch("subprocess.run") as mock_run:
+            res_mock = mock.Mock()
+            test_ret = 0
+            test_msg = b"Succeeded"
+            attrs = {"returncode": test_ret, "stderr": test_msg}
+            res_mock.configure_mock(**attrs)
+            mock_run.return_value = res_mock
+            service = "snmp"
+            systemd_service_stub = systemd_service.SystemdService(systemd_service.MOD_NAME)
+            ret, msg = systemd_service_stub.stop_service(service)
+            call_args = mock_run.call_args[0][0]
+            assert service in call_args
+            assert "/usr/bin/systemctl" in call_args
+            assert ret == test_ret, "Return value is wrong"
+            assert msg == "", "Return message is wrong"
+
+    @mock.patch("dbus.SystemBus")
+    @mock.patch("dbus.service.BusName")
+    @mock.patch("dbus.service.Object.__init__")
+    def test_service_stop_invalid(self, MockInit, MockBusName, MockSystemBus):
+        service = "unsupported service"
+        systemd_service_stub = systemd_service.SystemdService(systemd_service.MOD_NAME)
+        ret, msg = systemd_service_stub.stop_service(service)
+        assert ret == 1
+        assert "Dbus does not support" in msg
+
+    @mock.patch("dbus.SystemBus")
+    @mock.patch("dbus.service.BusName")
+    @mock.patch("dbus.service.Object.__init__")
+    def test_service_stop_empty(self, MockInit, MockBusName, MockSystemBus):
+        service = ""
+        systemd_service_stub = systemd_service.SystemdService(systemd_service.MOD_NAME)
+        ret, msg = systemd_service_stub.stop_service(service)
+        assert ret == 1
+        assert "stop_service called with no service specified" in msg