[counterpoll] make the 'eni' command functional only on the DPU (soni…

…c-net#3679)

- What I did
To make the 'eni' command only appear in the list of commands when the 'switch_type' is 'dpu'.
This way the "counterpoll --help" output shows only what is supported on the system.

Current output (contains "eni" while the switch_type is not "dpu"):

- How I did it
Added a register_dynamic_commands() to dynamically add the 'eni' command.
Updated the unit tests.

- How to verify it
Run the counterpoll_test.py test

Signed-off-by: Yakiv Huryk <yhuryk@nvidia.com>

counterpoll/main.py

@@ -397,15 +397,12 @@ def disable(ctx):
 
 
 # ENI counter commands
-@cli.group()
+@click.group()
 @click.pass_context
 def eni(ctx):
     """ ENI counter commands """
     ctx.obj = ConfigDBConnector()
     ctx.obj.connect()
-    if not is_dpu(ctx.obj):
-        click.echo("ENI counters are not supported on non DPU platforms")
-        exit(1)
 
 
 @eni.command(name='interval')
@@ -534,3 +531,27 @@ def disable(filename):
 def delay(filename):
     """ Delay counters in config_db file """
     _update_config_db_flex_counter_table("delay", filename)
+
+
+"""
+The list of dynamic commands that are added on a specific condition.
+Format:
+    (click group/command, callback function)
+"""
+dynamic_commands = [
+    (eni, is_dpu)
+]
+
+
+def register_dynamic_commands(cmds):
+    """
+    Dynamically register commands based on condition callback.
+    """
+    db = ConfigDBConnector()
+    db.connect()
+    for cmd, cb in cmds:
+        if cb(db):
+            cli.add_command(cmd)
+
+
+register_dynamic_commands(dynamic_commands)

tests/counterpoll_test.py

@@ -4,6 +4,7 @@
 import pytest
 import mock
 import sys
+import importlib
 from click.testing import CliRunner
 from shutil import copyfile
 from utilities_common.db import Db
@@ -248,13 +249,15 @@ def test_update_route_counter_interval(self):
     def test_update_eni_status(self, status):
         runner = CliRunner()
         result = runner.invoke(counterpoll.cli, ["eni", status])
-        assert result.exit_code == 1
-        assert result.output == "ENI counters are not supported on non DPU platforms\n"
+        assert 'No such command "eni"' in result.output
+        assert result.exit_code == 2
 
     @pytest.mark.parametrize("status", ["disable", "enable"])
     @mock.patch('counterpoll.main.device_info.get_platform_info')
     def test_update_eni_status_dpu(self, mock_get_platform_info, status):
         mock_get_platform_info.return_value = {'switch_type': 'dpu'}
+        importlib.reload(counterpoll)
+
         runner = CliRunner()
         db = Db()
 
@@ -267,6 +270,8 @@ def test_update_eni_status_dpu(self, mock_get_platform_info, status):
     @mock.patch('counterpoll.main.device_info.get_platform_info')
     def test_update_eni_interval(self, mock_get_platform_info):
         mock_get_platform_info.return_value = {'switch_type': 'dpu'}
+        importlib.reload(counterpoll)
+
         runner = CliRunner()
         db = Db()
         test_interval = "2000"