Fix the wrong permissions warning on the pgpass file (#16207)

* Fix the false warning on the pgpass file

The existing logic compares file modes using string comparison, which leads to false warnings on Python 3 due to the different mode representations ("0600" vs. "0o600"). To address this issue and enhance code efficiency, this PR proposes changing the comparison to an octal integer comparison. This not only eliminates false warnings but also ensures a more strict and faster comparison method, compatible with tools like "2to3".

Author: moonsn

gpMgmt/bin/gppylib/db/dbconn.py

@@ -38,9 +38,9 @@ def __init__(self):
             return
 
         st_info = os.stat(PGPASSFILE)
-        mode = str(oct(st_info[stat.ST_MODE] & 0o777))
+        mode = st_info[stat.ST_MODE] & 0o777
 
-        if mode != "0o600":
+        if mode != 0o600:
             print('WARNING: password file "%s" has group or world access; permissions should be u=rw (0600) or less' % PGPASSFILE)
             self.valid_pgpass = False
             return

gpMgmt/test/behave/mgmt_utils/gpstart.feature

@@ -8,11 +8,13 @@ Feature: gpstart behave tests
           And a mirror has crashed
           And the database is not running
          When the user runs "gpstart -a"
+	  And pgpassfile is exists
          Then gpstart should return a return code of 0
           And gpstart should print "Skipping startup of segment marked down in configuration" to stdout
           And gpstart should print "Skipped segment starts \(segments are marked down in configuration\) += 1" to stdout
           And gpstart should print "Successfully started [0-9]+ of [0-9]+ segment instances, skipped 1 other segments" to stdout
           And gpstart should print "Number of segments not attempted to start: 1" to stdout
+	  And gpstart should not print "permissions should be" to stdout
 
     Scenario: gpstart starts even if the standby host is unreachable
         Given the database is running

gpMgmt/test/behave/mgmt_utils/steps/gpstart.py

@@ -91,6 +91,21 @@ def impl(context, cmd):
     context.stdout_message, context.stderr_message = p.communicate()
     context.ret_code = p.returncode
 
+@when('pgpassfile is exists')
+def impl(context):
+    """
+    Create a pgpassfile
+    """
+    user_dir = os.path.expanduser("~")
+    file_name = '.pgpass'
+    file_path = os.path.join(user_dir, file_name)
+    if not os.path.exists(file_path):
+        try:
+            with open(file_path, "w") as file:
+                os.chmod(file_path, 0o600)
+        except Exception as e:
+            print("create pgpass file error")
+
 @given('the host for the {seg_type} on content {content} is made unreachable')
 def impl(context, seg_type, content):
     if seg_type == "primary":