Remove usage of not standard nc in remote_ops.py is_port_free

Author: vshepard

testgres/operations/remote_ops.py

@@ -10,6 +10,7 @@
 import logging
 import typing
 import copy
+import socket
 
 from ..exceptions import ExecUtilException
 from ..exceptions import InvalidOperationException
@@ -681,28 +682,24 @@ def get_process_children(self, pid):
     def is_port_free(self, number: int) -> bool:
         assert type(number) == int  # noqa: E721
 
-        cmd = ["nc", "-w", "5", "-z", "-v", "localhost", str(number)]
+        host = 'localhost'
+        port = number
+        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        sock.settimeout(5.0)
 
-        exit_status, output, error = self.exec_command(cmd=cmd, encoding=get_default_encoding(), ignore_errors=True, verbose=True)
-
-        assert type(output) == str  # noqa: E721
-        assert type(error) == str  # noqa: E721
-
-        if exit_status == 0:
-            return __class__._is_port_free__process_0(error)
-
-        if exit_status == 1:
-            return __class__._is_port_free__process_1(error)
-
-        errMsg = "nc returns an unknown result code: {0}".format(exit_status)
-
-        RaiseError.CommandExecutionError(
-            cmd=cmd,
-            exit_code=exit_status,
-            message=errMsg,
-            error=error,
-            out=output
-        )
+        try:
+            result = sock.connect_ex((host, port))
+            return result != 0
+        except Exception as e:
+            raise RaiseError.CommandExecutionError(
+                cmd=['socket.connect_ex', host, str(port)],
+                exit_code=getattr(e, 'errno', None),
+                message=f"Error checking port {port}: {e}",
+                error=str(e),
+                out=""
+            )
+        finally:
+            sock.close()
 
     def get_tempdir(self) -> str:
         command = ["mktemp", "-u", "-d"]
@@ -746,12 +743,7 @@ def _is_port_free__process_0(error: str) -> bool:
     @staticmethod
     def _is_port_free__process_1(error: str) -> bool:
         assert type(error) == str  # noqa: E721
-        #
-        # Example of error text:
-        #  "nc: connect to localhost (127.0.0.1) port 1024 (tcp) failed: Connection refused\n"
-        #
         # May be here is needed to check error message?
-        #
         return True
 
     @staticmethod