[config]Improve config save cli to save to one file for multiasic (sonic-net#3288)

HLD design : sonic-net/SONiC#1684

#### What I did
Add support for config save to one file for multi-aisc.
#### How I did it
Extend support for one file save for multiasic using the below format:
```
{
  "localhost": {/*host config*/},
  "asic0": {/*asic0 config*/},
  ...
  "asicN": {/*asicN config*/}
}
```
#### How to verify it
Unit test and manual test on multiasic platform.
Example running multi:
```
admin@str2-8800-sup-2:~$ sudo config save -y tmp.json
Integrate each ASIC's config into a single JSON file tmp.json.
admin@str2-8800-sup-2:~$ cat tmp.json |more
{
    "localhost": {
        "ACL_TABLE": {
            "NTP_ACL": {
                "policy_desc": "NTP_ACL",
                "services": [
                    "NTP"
...
    "asic0": {
        "AUTO_TECHSUPPORT": {
            "GLOBAL": {
                "available_mem_threshold": "10.0",
```

Author: wen587

config/main.py

@@ -1157,6 +1157,22 @@ def validate_gre_type(ctx, _, value):
     except ValueError:
         raise click.UsageError("{} is not a valid GRE type".format(value))
 
+
+def multi_asic_save_config(db, filename):
+    """A function to save all asic's config to single file
+    """
+    all_current_config = {}
+    cfgdb_clients = db.cfgdb_clients
+
+    for ns, config_db in cfgdb_clients.items():
+        current_config = config_db.get_config()
+        sonic_cfggen.FormatConverter.to_serialized(current_config)
+        asic_name = "localhost" if ns == DEFAULT_NAMESPACE else ns
+        all_current_config[asic_name] = sort_dict(current_config)
+    click.echo("Integrate each ASIC's config into a single JSON file {}.".format(filename))
+    with open(filename, 'w') as file:
+        json.dump(all_current_config, file, indent=4)
+
 # Function to apply patch for a single ASIC.
 def apply_patch_for_scope(scope_changes, results, config_format, verbose, dry_run, ignore_non_yang_tables, ignore_path):
     scope, changes = scope_changes
@@ -1276,7 +1292,8 @@ def config(ctx):
 @click.option('-y', '--yes', is_flag=True, callback=_abort_if_false,
                 expose_value=False, prompt='Existing files will be overwritten, continue?')
 @click.argument('filename', required=False)
-def save(filename):
+@clicommon.pass_db
+def save(db, filename):
     """Export current config DB to a file on disk.\n
        <filename> : Names of configuration file(s) to save, separated by comma with no spaces in between
     """
@@ -1291,7 +1308,13 @@ def save(filename):
     if filename is not None:
         cfg_files = filename.split(',')
 
-        if len(cfg_files) != num_cfg_file:
+        # If only one filename is provided in multi-ASIC mode,
+        # save all ASIC configurations to that single file.
+        if len(cfg_files) == 1 and multi_asic.is_multi_asic():
+            filename = cfg_files[0]
+            multi_asic_save_config(db, filename)
+            return
+        elif len(cfg_files) != num_cfg_file:
             click.echo("Input {} config file(s) separated by comma for multiple files ".format(num_cfg_file))
             return
 

tests/config_save_output/all_config_db.json

@@ -0,0 +1,5 @@
+{
+    "localhost": {},
+    "asic0": {},
+    "asic1": {}
+}

tests/config_test.py

@@ -168,6 +168,30 @@
 Reloading Monit configuration ...
 """
 
+save_config_output = """\
+Running command: /usr/local/bin/sonic-cfggen -d --print-data > /etc/sonic/config_db.json
+"""
+
+save_config_filename_output = """\
+Running command: /usr/local/bin/sonic-cfggen -d --print-data > /tmp/config_db.json
+"""
+
+save_config_masic_output = """\
+Running command: /usr/local/bin/sonic-cfggen -d --print-data > /etc/sonic/config_db.json
+Running command: /usr/local/bin/sonic-cfggen -n asic0 -d --print-data > /etc/sonic/config_db0.json
+Running command: /usr/local/bin/sonic-cfggen -n asic1 -d --print-data > /etc/sonic/config_db1.json
+"""
+
+save_config_filename_masic_output = """\
+Running command: /usr/local/bin/sonic-cfggen -d --print-data > config_db.json
+Running command: /usr/local/bin/sonic-cfggen -n asic0 -d --print-data > config_db0.json
+Running command: /usr/local/bin/sonic-cfggen -n asic1 -d --print-data > config_db1.json
+"""
+
+save_config_onefile_masic_output = """\
+Integrate each ASIC's config into a single JSON file /tmp/all_config_db.json.
+"""
+
 config_temp = {
         "scope": {
             "ACL_TABLE": {
@@ -333,6 +357,191 @@ def test_plattform_fw_update(self, mock_check_call):
         assert result.exit_code == 0
         mock_check_call.assert_called_with(["fwutil", "update", 'update', 'module', 'Module1', 'component', 'BIOS', 'fw'])
 
+
+class TestConfigSave(object):
+    @classmethod
+    def setup_class(cls):
+        os.environ['UTILITIES_UNIT_TESTING'] = "1"
+        print("SETUP")
+        import config.main
+        importlib.reload(config.main)
+
+    def test_config_save(self, get_cmd_module, setup_single_broadcom_asic):
+        def read_json_file_side_effect(filename):
+            return {}
+
+        with mock.patch("utilities_common.cli.run_command",
+                        mock.MagicMock(side_effect=mock_run_command_side_effect)),\
+            mock.patch('config.main.read_json_file',
+                       mock.MagicMock(side_effect=read_json_file_side_effect)),\
+            mock.patch('config.main.open',
+                       mock.MagicMock()):
+            (config, show) = get_cmd_module
+
+            runner = CliRunner()
+
+            result = runner.invoke(config.config.commands["save"], ["-y"])
+
+            print(result.exit_code)
+            print(result.output)
+            traceback.print_tb(result.exc_info[2])
+
+            assert result.exit_code == 0
+            assert "\n".join([li.rstrip() for li in result.output.split('\n')]) == save_config_output
+
+    def test_config_save_filename(self, get_cmd_module, setup_single_broadcom_asic):
+        def read_json_file_side_effect(filename):
+            return {}
+
+        with mock.patch("utilities_common.cli.run_command",
+                        mock.MagicMock(side_effect=mock_run_command_side_effect)),\
+            mock.patch('config.main.read_json_file',
+                       mock.MagicMock(side_effect=read_json_file_side_effect)),\
+            mock.patch('config.main.open',
+                       mock.MagicMock()):
+
+            (config, show) = get_cmd_module
+
+            runner = CliRunner()
+
+            output_file = os.path.join(os.sep, "tmp", "config_db.json")
+            result = runner.invoke(config.config.commands["save"], ["-y", output_file])
+
+            print(result.exit_code)
+            print(result.output)
+            traceback.print_tb(result.exc_info[2])
+
+            assert result.exit_code == 0
+            assert "\n".join([li.rstrip() for li in result.output.split('\n')]) == save_config_filename_output
+
+    @classmethod
+    def teardown_class(cls):
+        print("TEARDOWN")
+        os.environ['UTILITIES_UNIT_TESTING'] = "0"
+
+
+class TestConfigSaveMasic(object):
+    @classmethod
+    def setup_class(cls):
+        print("SETUP")
+        os.environ['UTILITIES_UNIT_TESTING'] = "2"
+        os.environ["UTILITIES_UNIT_TESTING_TOPOLOGY"] = "multi_asic"
+        import config.main
+        importlib.reload(config.main)
+        # change to multi asic config
+        from .mock_tables import dbconnector
+        from .mock_tables import mock_multi_asic
+        importlib.reload(mock_multi_asic)
+        dbconnector.load_namespace_config()
+
+    def test_config_save_masic(self):
+        def read_json_file_side_effect(filename):
+            return {}
+
+        with mock.patch("utilities_common.cli.run_command",
+                        mock.MagicMock(side_effect=mock_run_command_side_effect)),\
+            mock.patch('config.main.read_json_file',
+                       mock.MagicMock(side_effect=read_json_file_side_effect)),\
+            mock.patch('config.main.open',
+                       mock.MagicMock()):
+
+            runner = CliRunner()
+
+            result = runner.invoke(config.config.commands["save"], ["-y"])
+
+            print(result.exit_code)
+            print(result.output)
+            traceback.print_tb(result.exc_info[2])
+
+            assert result.exit_code == 0
+            assert "\n".join([li.rstrip() for li in result.output.split('\n')]) == save_config_masic_output
+
+    def test_config_save_filename_masic(self):
+        def read_json_file_side_effect(filename):
+            return {}
+
+        with mock.patch("utilities_common.cli.run_command",
+                        mock.MagicMock(side_effect=mock_run_command_side_effect)),\
+            mock.patch('config.main.read_json_file',
+                       mock.MagicMock(side_effect=read_json_file_side_effect)),\
+            mock.patch('config.main.open',
+                       mock.MagicMock()):
+
+            runner = CliRunner()
+
+            result = runner.invoke(
+                config.config.commands["save"],
+                ["-y", "config_db.json,config_db0.json,config_db1.json"]
+            )
+
+            print(result.exit_code)
+            print(result.output)
+            traceback.print_tb(result.exc_info[2])
+
+            assert result.exit_code == 0
+            assert "\n".join([li.rstrip() for li in result.output.split('\n')]) == save_config_filename_masic_output
+
+    def test_config_save_filename_wrong_cnt_masic(self):
+        def read_json_file_side_effect(filename):
+            return {}
+
+        with mock.patch('config.main.read_json_file', mock.MagicMock(side_effect=read_json_file_side_effect)):
+
+            runner = CliRunner()
+
+            result = runner.invoke(
+                config.config.commands["save"],
+                ["-y", "config_db.json,config_db0.json"]
+            )
+
+            print(result.exit_code)
+            print(result.output)
+            traceback.print_tb(result.exc_info[2])
+
+            assert "Input 3 config file(s) separated by comma for multiple files" in result.output
+
+    def test_config_save_onefile_masic(self):
+        def get_config_side_effect():
+            return {}
+
+        with mock.patch('swsscommon.swsscommon.ConfigDBConnector.get_config',
+                        mock.MagicMock(side_effect=get_config_side_effect)):
+            runner = CliRunner()
+
+            output_file = os.path.join(os.sep, "tmp", "all_config_db.json")
+            print("Saving output in {}".format(output_file))
+            try:
+                os.remove(output_file)
+            except OSError:
+                pass
+            result = runner.invoke(
+                config.config.commands["save"],
+                ["-y", output_file]
+            )
+
+            print(result.exit_code)
+            print(result.output)
+            assert result.exit_code == 0
+            assert "\n".join([li.rstrip() for li in result.output.split('\n')]) == save_config_onefile_masic_output
+
+            cwd = os.path.dirname(os.path.realpath(__file__))
+            expected_result = os.path.join(
+                cwd, "config_save_output", "all_config_db.json"
+            )
+            assert filecmp.cmp(output_file, expected_result, shallow=False)
+
+    @classmethod
+    def teardown_class(cls):
+        print("TEARDOWN")
+        os.environ['UTILITIES_UNIT_TESTING'] = "0"
+        os.environ["UTILITIES_UNIT_TESTING_TOPOLOGY"] = ""
+        # change back to single asic config
+        from .mock_tables import dbconnector
+        from .mock_tables import mock_single_asic
+        importlib.reload(mock_single_asic)
+        dbconnector.load_namespace_config()
+
+
 class TestConfigReload(object):
     dummy_cfg_file = os.path.join(os.sep, "tmp", "config.json")
 
@@ -2889,4 +3098,4 @@ def teardown_class(cls):
         from .mock_tables import dbconnector
         from .mock_tables import mock_single_asic
         importlib.reload(mock_single_asic)
-        dbconnector.load_database_config()
+        dbconnector.load_database_config()