[show] Add bgpraw to show run all (sonic-net#2537)

#### What I did
Add bgpraw output to `show runningconfiguration all`
```
Requirements:
1. current `show runningconfig` will print all the ConfigDB in a json format, we need to add a new key-value into the json output "bgpraw" with a long string value
2. The long string value should be the output of `vtysh -c "show run"`. It is normally multiline string, may include special characters like \". Need to make sure the escaping properly
3. We do not need to insert the key-value into ConfigDB is not existing there
4. If ConfigDB already has the key-value, we do not need to override it by vtysh command output
5. Not break multi-asic use
```
#### How I did it
Generate bgpraw output then append it to `show runnningconfiguration all`'s output
#### How to verify it
Mannual test
#### Previous command output (if the output of a command-line utility has changed)
```
admin@vlab-01:~$ show run all
{
    "ACL_TABLE": {
......
    "WRED_PROFILE": {
        "AZURE_LOSSLESS": {
            "ecn": "ecn_all",
            "green_drop_probability": "5",
            "green_max_threshold": "2097152",
            "green_min_threshold": "1048576",
            "red_drop_probability": "5",
            "red_max_threshold": "2097152",
            "red_min_threshold": "1048576",
            "wred_green_enable": "true",
            "wred_red_enable": "true",
            "wred_yellow_enable": "true",
            "yellow_drop_probability": "5",
            "yellow_max_threshold": "2097152",
            "yellow_min_threshold": "1048576"
        }
    }
}
```
#### New command output (if the output of a command-line utility has changed)
```
admin@vlab-01:~$ show run all
{
    "ACL_TABLE": {
......
    "WRED_PROFILE": {
        "AZURE_LOSSLESS": {
            "ecn": "ecn_all",
            "green_drop_probability": "5",
            "green_max_threshold": "2097152",
            "green_min_threshold": "1048576",
            "red_drop_probability": "5",
            "red_max_threshold": "2097152",
            "red_min_threshold": "1048576",
            "wred_green_enable": "true",
            "wred_red_enable": "true",
            "wred_yellow_enable": "true",
            "yellow_drop_probability": "5",
            "yellow_max_threshold": "2097152",
            "yellow_min_threshold": "1048576"
        }
    },
    "bgpraw": "Building configuration...\n\nCurrent configuration......end\n"
}
```

show/main.py

@@ -19,6 +19,7 @@
 from datetime import datetime
 import utilities_common.constants as constants
 from utilities_common.general import load_db_config
+from json.decoder import JSONDecodeError
 
 # mock the redis for unit test purposes #
 try:
@@ -129,6 +130,10 @@ def run_command(command, display_cmd=False, return_cmd=False):
     if rc != 0:
         sys.exit(rc)
 
+def get_cmd_output(cmd):
+    proc = subprocess.Popen(cmd, text=True, stdout=subprocess.PIPE)
+    return proc.communicate()[0], proc.returncode
+
 # Lazy global class instance for SONiC interface name to alias conversion
 iface_alias_converter = lazy_object_proxy.Proxy(lambda: clicommon.InterfaceAliasConverter())
 
@@ -1383,8 +1388,25 @@ def runningconfiguration():
 @click.option('--verbose', is_flag=True, help="Enable verbose output")
 def all(verbose):
     """Show full running configuration"""
-    cmd = "sonic-cfggen -d --print-data"
-    run_command(cmd, display_cmd=verbose)
+    cmd = ['sonic-cfggen', '-d', '--print-data']
+    stdout, rc = get_cmd_output(cmd)
+    if rc:
+        click.echo("Failed to get cmd output '{}':rc {}".format(cmd, rc))
+        raise click.Abort()
+
+    try:
+        output = json.loads(stdout)
+    except JSONDecodeError as e:
+        click.echo("Failed to load output '{}':{}".format(cmd, e))
+        raise click.Abort()
+
+    if not multi_asic.is_multi_asic():
+        bgpraw_cmd = [constants.RVTYSH_COMMAND, '-c', 'show running-config']
+        bgpraw, rc = get_cmd_output(bgpraw_cmd)
+        if rc:
+            bgpraw = ""
+        output['bgpraw'] = bgpraw
+    click.echo(json.dumps(output, indent=4))
 
 
 # 'acl' subcommand ("show runningconfiguration acl")

tests/show_test.py

@@ -0,0 +1,51 @@
+import os
+import sys
+import show.main as show
+from click.testing import CliRunner
+from unittest import mock
+from unittest.mock import call, MagicMock
+
+test_path = os.path.dirname(os.path.abspath(__file__))
+modules_path = os.path.dirname(test_path)
+sys.path.insert(0, test_path)
+sys.path.insert(0, modules_path)
+
+
+class TestShowRunAllCommands(object):
+    @classmethod
+    def setup_class(cls):
+        print("SETUP")
+        os.environ["UTILITIES_UNIT_TESTING"] = "1"
+
+    def test_show_runningconfiguration_all_json_loads_failure(self):
+        def get_cmd_output_side_effect(*args, **kwargs):
+            return "", 0
+        with mock.patch('show.main.get_cmd_output',
+                mock.MagicMock(side_effect=get_cmd_output_side_effect)) as mock_get_cmd_output:
+            result = CliRunner().invoke(show.cli.commands['runningconfiguration'].commands['all'], [])
+        assert result.exit_code != 0
+
+    def test_show_runningconfiguration_all_get_cmd_ouput_failure(self):
+        def get_cmd_output_side_effect(*args, **kwargs):
+            return "{}", 2
+        with mock.patch('show.main.get_cmd_output',
+                mock.MagicMock(side_effect=get_cmd_output_side_effect)) as mock_get_cmd_output:
+            result = CliRunner().invoke(show.cli.commands['runningconfiguration'].commands['all'], [])
+        assert result.exit_code != 0
+
+    def test_show_runningconfiguration_all(self):
+        def get_cmd_output_side_effect(*args, **kwargs):
+            return "{}", 0
+        with mock.patch('show.main.get_cmd_output',
+                mock.MagicMock(side_effect=get_cmd_output_side_effect)) as mock_get_cmd_output:
+            result = CliRunner().invoke(show.cli.commands['runningconfiguration'].commands['all'], [])
+        assert mock_get_cmd_output.call_count == 2
+        assert mock_get_cmd_output.call_args_list == [
+            call(['sonic-cfggen', '-d', '--print-data']),
+            call(['rvtysh', '-c', 'show running-config'])]
+
+    @classmethod
+    def teardown_class(cls):
+        print("TEARDOWN")
+        os.environ["PATH"] = os.pathsep.join(os.environ["PATH"].split(os.pathsep)[:-1])
+        os.environ["UTILITIES_UNIT_TESTING"] = "0"