[202012][show] show logging CLI support for logs stored in tmpfs (sonic-net#2652)

Signed-off-by: Mihir Patel <patelmi@microsoft.com>

Author: mihirpat1

show/main.py

@@ -916,14 +916,18 @@ def table(verbose):
 @click.option('--verbose', is_flag=True, help="Enable verbose output")
 def logging(process, lines, follow, verbose):
     """Show system log"""
+    if os.path.exists("/var/log.tmpfs"):
+        log_path = "/var/log.tmpfs"
+    else:
+        log_path = "/var/log"
     if follow:
-        cmd = "sudo tail -F /var/log/syslog"
+        cmd = "sudo tail -F {}/syslog".format(log_path)
         run_command(cmd, display_cmd=verbose)
     else:
-        if os.path.isfile("/var/log/syslog.1"):
-            cmd = "sudo cat /var/log/syslog.1 /var/log/syslog"
+        if os.path.isfile("{}/syslog.1".format(log_path)):
+            cmd = "sudo cat {}/syslog.1 {}/syslog".format(log_path, log_path)
         else:
-            cmd = "sudo cat /var/log/syslog"
+            cmd = "sudo cat {}/syslog".format(log_path)
 
         if process is not None:
             cmd += " | grep '{}'".format(process)

tests/show_test.py

@@ -0,0 +1,70 @@
+import pytest
+import show.main as show
+from click.testing import CliRunner
+from unittest.mock import MagicMock, patch
+
+EXPECTED_BASE_COMMAND = 'sudo '
+
+@patch('show.main.run_command')
+@pytest.mark.parametrize(
+        "cli_arguments,expected",
+        [
+            ([], 'cat /var/log/syslog'),
+            (['xcvrd'], "cat /var/log/syslog | grep 'xcvrd'"),
+            (['-l', '10'], 'cat /var/log/syslog | tail -10'),
+            (['-f'], 'tail -F /var/log/syslog'),
+        ]
+)
+def test_show_logging_default(run_command, cli_arguments, expected):
+    runner = CliRunner()
+    result = runner.invoke(show.cli.commands["logging"], cli_arguments)
+    run_command.assert_called_with(EXPECTED_BASE_COMMAND + expected, display_cmd=False)
+
+@patch('show.main.run_command')
+@patch('os.path.isfile', MagicMock(return_value=True))
+@pytest.mark.parametrize(
+        "cli_arguments,expected",
+        [
+            ([], 'cat /var/log/syslog.1 /var/log/syslog'),
+            (['xcvrd'], "cat /var/log/syslog.1 /var/log/syslog | grep 'xcvrd'"),
+            (['-l', '10'], 'cat /var/log/syslog.1 /var/log/syslog | tail -10'),
+            (['-f'], 'tail -F /var/log/syslog'),
+        ]
+)
+def test_show_logging_syslog_1(run_command, cli_arguments, expected):
+    runner = CliRunner()
+    result = runner.invoke(show.cli.commands["logging"], cli_arguments)
+    run_command.assert_called_with(EXPECTED_BASE_COMMAND + expected, display_cmd=False)
+
+@patch('show.main.run_command')
+@patch('os.path.exists', MagicMock(return_value=True))
+@pytest.mark.parametrize(
+        "cli_arguments,expected",
+        [
+            ([], 'cat /var/log.tmpfs/syslog'),
+            (['xcvrd'], "cat /var/log.tmpfs/syslog | grep 'xcvrd'"),
+            (['-l', '10'], 'cat /var/log.tmpfs/syslog | tail -10'),
+            (['-f'], 'tail -F /var/log.tmpfs/syslog'),
+        ]
+)
+def test_show_logging_tmpfs(run_command, cli_arguments, expected):
+    runner = CliRunner()
+    result = runner.invoke(show.cli.commands["logging"], cli_arguments)
+    run_command.assert_called_with(EXPECTED_BASE_COMMAND + expected, display_cmd=False)
+
+@patch('show.main.run_command')
+@patch('os.path.isfile', MagicMock(return_value=True))
+@patch('os.path.exists', MagicMock(return_value=True))
+@pytest.mark.parametrize(
+        "cli_arguments,expected",
+        [
+            ([], 'cat /var/log.tmpfs/syslog.1 /var/log.tmpfs/syslog'),
+            (['xcvrd'], "cat /var/log.tmpfs/syslog.1 /var/log.tmpfs/syslog | grep 'xcvrd'"),
+            (['-l', '10'], 'cat /var/log.tmpfs/syslog.1 /var/log.tmpfs/syslog | tail -10'),
+            (['-f'], 'tail -F /var/log.tmpfs/syslog'),
+        ]
+)
+def test_show_logging_tmpfs_syslog_1(run_command, cli_arguments, expected):
+    runner = CliRunner()
+    result = runner.invoke(show.cli.commands["logging"], cli_arguments)
+    run_command.assert_called_with(EXPECTED_BASE_COMMAND + expected, display_cmd=False)