advanced cmd options for streamer

kvmd/apps/__init__.py

@@ -73,6 +73,7 @@ from ..validators.os import valid_abs_path
 from ..validators.os import valid_abs_file
 from ..validators.os import valid_abs_dir
 from ..validators.os import valid_unix_mode
+from ..validators.os import valid_options
 from ..validators.os import valid_command
 
 from ..validators.net import valid_ip_or_host
@@ -363,7 +364,9 @@ def _get_config_scheme() -> Dict:
 
                 "process_name_prefix": Option("kvmd/streamer"),
 
-                "cmd": Option(["/bin/true"], type=valid_command),
+                "cmd":        Option(["/bin/true"], type=valid_command),
+                "cmd_remove": Option([], type=valid_options),
+                "cmd_append": Option([], type=valid_options),
             },
 
             "snapshot": {

kvmd/apps/kvmd/streamer.py

@@ -132,6 +132,8 @@ class Streamer:  # pylint: disable=too-many-instance-attributes
         process_name_prefix: str,
 
         cmd: List[str],
+        cmd_remove: List[str],
+        cmd_append: List[str],
 
         **params_kwargs: Any,
     ) -> None:
@@ -148,7 +150,11 @@ class Streamer:  # pylint: disable=too-many-instance-attributes
 
         self.__process_name_prefix = process_name_prefix
 
-        self.__cmd = cmd
+        self.__cmd = [
+            cmd[0],  # Executable
+            *filter((lambda item: item not in cmd_remove), cmd[1:]),
+            *cmd_append,
+        ]
 
         self.__params = _StreamerParams(**params_kwargs)
 

kvmd/validators/os.py

@@ -94,8 +94,14 @@ def valid_unix_mode(arg: Any) -> int:
     return int(valid_number(arg, min=0, name="UNIX mode"))
 
 
+def valid_options(arg: Any, name: str="") -> List[str]:
+    if not name:
+        name = "options"
+    return valid_string_list(arg, delim=r"[,\t]+", name=name)
+
+
 def valid_command(arg: Any) -> List[str]:
-    cmd = valid_string_list(arg, delim=r"[,\t]+", name="command")
+    cmd = valid_options(arg, name="command")
     if len(cmd) == 0:
         raise_error(arg, "command")
     cmd[0] = valid_abs_file(cmd[0], name="command entry point")