[CLI] Move hostname, mgmt interface/vrf config to hostcfgd (#2173)

- Why I did it
To be able to configure the management interface and hostname standalone by changing database config at runtime.
From the CLI perspective fo view, the following behavior is the same. But now you have two ways of configuring it: CLI, directly through the database.

- How I did it
Moved configuration part of the interface and hostname to "hostcfgd".

- How to verify it
Built an image
Flash it to the switch
Run CLI commands

Signed-off-by: Yevhen Fastiuk <yfastiuk@nvidia.com>

config/main.py

@@ -22,6 +22,7 @@
 from sonic_py_common import device_info, multi_asic
 from sonic_py_common.interface import get_interface_table_name, get_port_table_name, get_intf_longname
 from utilities_common import util_base
+from swsscommon import swsscommon
 from swsscommon.swsscommon import SonicV2Connector, ConfigDBConnector
 from utilities_common.db import Db
 from utilities_common.intf_filter import parse_interface_in_filter
@@ -1884,19 +1885,11 @@ def hostname(new_hostname):
 
     config_db = ConfigDBConnector()
     config_db.connect()
-    config_db.mod_entry('DEVICE_METADATA' , 'localhost', {"hostname" : new_hostname})
-    try:
-        command = "service hostname-config restart"
-        clicommon.run_command(command, display_cmd=True)
-    except SystemExit as e:
-        click.echo("Restarting hostname-config  service failed with error {}".format(e))
-        raise
+    config_db.mod_entry(swsscommon.CFG_DEVICE_METADATA_TABLE_NAME, 'localhost',
+                        {'hostname': new_hostname})
 
-    # Reload Monit configuration to pick up new hostname in case it changed
-    click.echo("Reloading Monit configuration ...")
-    clicommon.run_command("sudo monit reload")
-
-    click.echo("Please note loaded setting will be lost after system reboot. To preserve setting, run `config save`.")
+    click.echo('Please note loaded setting will be lost after system reboot. To'
+               ' preserve setting, run `config save`.')
 
 #
 # 'synchronous_mode' command ('config synchronous_mode ...')
@@ -2837,22 +2830,6 @@ def warm_restart_bgp_eoiu(ctx, enable):
     db = ctx.obj['db']
     db.mod_entry('WARM_RESTART', 'bgp', {'bgp_eoiu': enable})
 
-def mvrf_restart_services():
-    """Restart interfaces-config service and NTP service when mvrf is changed"""
-    """
-    When mvrf is enabled, eth0 should be moved to mvrf; when it is disabled,
-    move it back to default vrf. Restarting the "interfaces-config" service
-    will recreate the /etc/network/interfaces file and restart the
-    "networking" service that takes care of the eth0 movement.
-    NTP service should also be restarted to rerun the NTP service with or
-    without "cgexec" accordingly.
-    """
-    cmd="service ntp stop"
-    os.system (cmd)
-    cmd="systemctl restart interfaces-config"
-    os.system (cmd)
-    cmd="service ntp start"
-    os.system (cmd)
 
 def vrf_add_management_vrf(config_db):
     """Enable management vrf in config DB"""
@@ -2862,22 +2839,7 @@ def vrf_add_management_vrf(config_db):
         click.echo("ManagementVRF is already Enabled.")
         return None
     config_db.mod_entry('MGMT_VRF_CONFIG', "vrf_global", {"mgmtVrfEnabled": "true"})
-    mvrf_restart_services()
-    """
-    The regular expression for grep in below cmd is to match eth0 line in /proc/net/route, sample file:
-    $ cat /proc/net/route
-        Iface   Destination     Gateway         Flags   RefCnt  Use     Metric  Mask            MTU     Window  IRTT
-         eth0    00000000        01803B0A        0003    0       0       202     00000000        0       0       0
-    """
-    cmd = r"cat /proc/net/route | grep -E \"eth0\s+00000000\s+[0-9A-Z]+\s+[0-9]+\s+[0-9]+\s+[0-9]+\s+202\" | wc -l"
-    proc = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE)
-    output = proc.communicate()
-    if int(output[0]) >= 1:
-        cmd="ip -4 route del default dev eth0 metric 202"
-        proc = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE)
-        proc.communicate()
-        if proc.returncode != 0:
-            click.echo("Could not delete eth0 route")
+
 
 def vrf_delete_management_vrf(config_db):
     """Disable management vrf in config DB"""
@@ -2887,7 +2849,7 @@ def vrf_delete_management_vrf(config_db):
         click.echo("ManagementVRF is already Disabled.")
         return None
     config_db.mod_entry('MGMT_VRF_CONFIG', "vrf_global", {"mgmtVrfEnabled": "false"})
-    mvrf_restart_services()
+
 
 @config.group(cls=clicommon.AbbreviationGroup)
 @click.pass_context
@@ -4123,20 +4085,6 @@ def _get_all_mgmtinterface_keys():
     config_db.connect()
     return list(config_db.get_table('MGMT_INTERFACE').keys())
 
-def mgmt_ip_restart_services():
-    """Restart the required services when mgmt inteface IP address is changed"""
-    """
-    Whenever the eth0 IP address is changed, restart the "interfaces-config"
-    service which regenerates the /etc/network/interfaces file and restarts
-    the networking service to make the new/null IP address effective for eth0.
-    "ntp-config" service should also be restarted based on the new
-    eth0 IP address since the ntp.conf (generated from ntp.conf.j2) is
-    made to listen on that particular eth0 IP address or reset it back.
-    """
-    cmd="systemctl restart interfaces-config"
-    os.system (cmd)
-    cmd="systemctl restart ntp-config"
-    os.system (cmd)
 
 #
 # 'mtu' subcommand
@@ -4282,7 +4230,6 @@ def add(ctx, interface_name, ip_addr, gw):
             config_db.set_entry("MGMT_INTERFACE", (interface_name, str(ip_address)), {"NULL": "NULL"})
         else:
             config_db.set_entry("MGMT_INTERFACE", (interface_name, str(ip_address)), {"gwaddr": gw})
-        mgmt_ip_restart_services()
 
         return
 
@@ -4322,7 +4269,6 @@ def remove(ctx, interface_name, ip_addr):
 
     if interface_name == 'eth0':
         config_db.set_entry("MGMT_INTERFACE", (interface_name, str(ip_address)), None)
-        mgmt_ip_restart_services()
         return
 
     table_name = get_interface_table_name(interface_name)

tests/config_test.py

@@ -1580,3 +1580,37 @@ def test_config_rate(self, get_cmd_module, setup_single_broadcom_asic):
     def teardown_class(cls):
         print("TEARDOWN")
         os.environ['UTILITIES_UNIT_TESTING'] = "0"
+
+
+class TestConfigHostname(object):
+    @classmethod
+    def setup_class(cls):
+        print("SETUP")
+        import config.main
+        importlib.reload(config.main)
+
+    @mock.patch('config.main.ConfigDBConnector')
+    def test_hostname_add(self, db_conn_patch, get_cmd_module):
+        db_conn_patch().mod_entry = mock.Mock()
+        (config, show) = get_cmd_module
+
+        runner = CliRunner()
+        result = runner.invoke(config.config.commands["hostname"],
+                               ["new_hostname"])
+
+        # Verify success
+        assert result.exit_code == 0
+
+        # Check was called
+        args_list = db_conn_patch().mod_entry.call_args_list
+        assert len(args_list) > 0
+
+        args, _ = args_list[0]
+        assert len(args) > 0
+
+        # Check new hostname was part of args
+        assert {'hostname': 'new_hostname'} in args
+
+    @classmethod
+    def teardown_class(cls):
+        print("TEARDOWN")