[Config] Update config command of kdump (sonic-net#1700)

Signed-off-by: Yong Zhao yozhao@microsoft.com

What I did
This PR aims to update the config command of Kdump (Linux kernel dump) mechanism.

How I did it
Before updating the value of a field in the table of KDUMP, we need decide whether the KDUMP table and corresponding field does exist in the table.

How to verify it
I verifies this on device str-msn2700-03 and unit test passed.

    tests/kdump_test.py::TestKdump::test_config_kdump_disable PASSED                                                                                                 
    tests/kdump_test.py::TestKdump::test_config_kdump_enable PASSED                                                                                                  
    tests/kdump_test.py::TestKdump::test_config_kdump_memory PASSED                                                                                                  
    tests/kdump_test.py::TestKdump::test_config_kdump_num_dumps PASSED

config/kdump.py

@@ -1,44 +1,86 @@
-import os
+import sys
+
 import click
-import utilities_common.cli as clicommon
-from swsscommon.swsscommon import ConfigDBConnector
+from utilities_common.cli import AbbreviationGroup, pass_db
+
 
-@click.group(cls=clicommon.AbbreviationGroup, name="kdump")
+#
+# 'kdump' group ('sudo config kdump ...')
+#
+@click.group(cls=AbbreviationGroup, name="kdump")
 def kdump():
-    """ Configure kdump """
-    if os.geteuid() != 0:
-        exit("Root privileges are required for this operation")
-
-@kdump.command()
-def disable():
-    """Disable kdump operation"""
-    config_db = ConfigDBConnector()
-    if config_db is not None:
-        config_db.connect()
-        config_db.mod_entry("KDUMP", "config", {"enabled": "false"})
-
-@kdump.command()
-def enable():
-    """Enable kdump operation"""
-    config_db = ConfigDBConnector()
-    if config_db is not None:
-        config_db.connect()
-        config_db.mod_entry("KDUMP", "config", {"enabled": "true"})
-
-@kdump.command()
+    """Configure the KDUMP mechanism"""
+    pass
+
+
+def check_kdump_table_existence(kdump_table):
+    """Checks whether the 'KDUMP' table is configured in Config DB.
+
+    Args:
+      kdump_table: A dictionary represents the key-value pair in sub-table
+      of 'KDUMP'.
+
+    Returns:
+      None.
+    """
+    if not kdump_table:
+        click.echo("Unable to retrieve 'KDUMP' table from Config DB.")
+        sys.exit(1)
+
+    if "config" not in kdump_table:
+        click.echo("Unable to retrieve key 'config' from KDUMP table.")
+        sys.exit(2)
+
+
+#
+# 'disable' command ('sudo config kdump disable')
+#
+@kdump.command(name="disable", short_help="Disable the KDUMP mechanism")
+@pass_db
+def kdump_disable(db):
+    """Disable the KDUMP mechanism"""
+    kdump_table = db.cfgdb.get_table("KDUMP")
+    check_kdump_table_existence(kdump_table)
+
+    db.cfgdb.mod_entry("KDUMP", "config", {"enabled": "false"})
+
+
+#
+# 'enable' command ('sudo config kdump enable')
+#
+@kdump.command(name="enable", short_help="Enable the KDUMP mechanism")
+@pass_db
+def kdump_enable(db):
+    """Enable the KDUMP mechanism"""
+    kdump_table = db.cfgdb.get_table("KDUMP")
+    check_kdump_table_existence(kdump_table)
+
+    db.cfgdb.mod_entry("KDUMP", "config", {"enabled": "true"})
+
+
+#
+# 'memory' command ('sudo config kdump memory ...')
+#
+@kdump.command(name="memory", short_help="Configure the memory for KDUMP mechanism")
 @click.argument('kdump_memory', metavar='<kdump_memory>', required=True)
-def memory(kdump_memory):
-    """Set memory allocated for kdump capture kernel"""
-    config_db = ConfigDBConnector()
-    if config_db is not None:
-        config_db.connect()
-        config_db.mod_entry("KDUMP", "config", {"memory": kdump_memory})
-
-@kdump.command('num-dumps')
+@pass_db
+def kdump_memory(db, kdump_memory):
+    """Reserve memory for kdump capture kernel"""
+    kdump_table = db.cfgdb.get_table("KDUMP")
+    check_kdump_table_existence(kdump_table)
+
+    db.cfgdb.mod_entry("KDUMP", "config", {"memory": kdump_memory})
+
+
+#
+# 'num_dumps' command ('sudo config keump num_dumps ...')
+#
+@kdump.command(name="num_dumps", short_help="Configure the maximum dump files of KDUMP mechanism")
 @click.argument('kdump_num_dumps', metavar='<kdump_num_dumps>', required=True, type=int)
-def num_dumps(kdump_num_dumps):
-    """Set max number of dump files for kdump"""
-    config_db = ConfigDBConnector()
-    if config_db is not None:
-        config_db.connect()
-        config_db.mod_entry("KDUMP", "config", {"num_dumps": kdump_num_dumps})
+@pass_db
+def kdump_num_dumps(db, kdump_num_dumps):
+    """Set maximum number of dump files for kdump"""
+    kdump_table = db.cfgdb.get_table("KDUMP")
+    check_kdump_table_existence(kdump_table)
+
+    db.cfgdb.mod_entry("KDUMP", "config", {"num_dumps": kdump_num_dumps})

tests/kdump_test.py

@@ -0,0 +1,74 @@
+import importlib
+
+from click.testing import CliRunner
+from utilities_common.db import Db
+
+
+class TestKdump(object):
+    @classmethod
+    def setup_class(cls):
+        print("SETUP")
+
+    def test_config_kdump_disable(self, get_cmd_module):
+        (config, show) = get_cmd_module
+        db = Db()
+        runner = CliRunner()
+        result = runner.invoke(config.config.commands["kdump"].commands["disable"], obj=db)
+        print(result.exit_code)
+        assert result.exit_code == 0
+
+        # Delete the 'KDUMP' table.
+        db.cfgdb.delete_table("KDUMP")
+
+        result = runner.invoke(config.config.commands["kdump"].commands["disable"], obj=db)
+        print(result.exit_code)
+        assert result.exit_code == 1
+
+    def test_config_kdump_enable(self, get_cmd_module):
+        (config, show) = get_cmd_module
+        db = Db()
+        runner = CliRunner()
+        result = runner.invoke(config.config.commands["kdump"].commands["enable"], obj=db)
+        print(result.exit_code)
+        assert result.exit_code == 0
+
+        # Delete the 'KDUMP' table.
+        db.cfgdb.delete_table("KDUMP")
+
+        result = runner.invoke(config.config.commands["kdump"].commands["enable"], obj=db)
+        print(result.exit_code)
+        assert result.exit_code == 1
+
+    def test_config_kdump_memory(self, get_cmd_module):
+        (config, show) = get_cmd_module
+        db = Db()
+        runner = CliRunner()
+        result = runner.invoke(config.config.commands["kdump"].commands["memory"], ["256MB"], obj=db)
+        print(result.exit_code)
+        assert result.exit_code == 0
+
+        # Delete the 'KDUMP' table.
+        db.cfgdb.delete_table("KDUMP")
+
+        result = runner.invoke(config.config.commands["kdump"].commands["memory"], ["256MB"], obj=db)
+        print(result.exit_code)
+        assert result.exit_code == 1
+
+    def test_config_kdump_num_dumps(self, get_cmd_module):
+        (config, show) = get_cmd_module
+        db = Db()
+        runner = CliRunner()
+        result = runner.invoke(config.config.commands["kdump"].commands["num_dumps"], ["10"], obj=db)
+        print(result.exit_code)
+        assert result.exit_code == 0
+
+        # Delete the 'KDUMP' table.
+        db.cfgdb.delete_table("KDUMP")
+
+        result = runner.invoke(config.config.commands["kdump"].commands["num_dumps"], ["10"], obj=db)
+        print(result.exit_code)
+        assert result.exit_code == 1
+
+    @classmethod
+    def teardown_class(cls):
+        print("TEARDOWN")

tests/mock_tables/config_db.json

@@ -684,6 +684,11 @@
     "DEBUG_COUNTER_DROP_REASON|DEBUG_2|IP_HEADER_ERROR": {},
     "DEBUG_COUNTER_DROP_REASON|DEBUG_2|NO_L3_HEADER": {},
     "DEBUG_COUNTER_DROP_REASON|lowercase_counter|L2_ANY": {},
+    "KDUMP|config": {
+        "enabled": "false",
+        "memory": "256MB",
+        "num_dumps": "3"
+    },
     "FEATURE|bgp": {
         "state": "enabled",
         "auto_restart": "enabled",