lib.ExecContext.username: Add property

Add the property .username, backed by the protected _username()
callback. It should return the user run()'s cmd parameter is executed
as.

Signed-off-by: Jan Lindemann <jan@janware.com>

src/python/jw/pkg/lib/ExecContext.py

@@ -240,9 +240,13 @@ class ExecContext(Base):
         super().__init__(uri=uri, interactive=interactive, verbose_default=verbose_default)
 
     @abc.abstractmethod
-    async def _run(self, *args, **kwargs) -> Result:
+    def _username(self) -> str:
         pass
 
+    @property
+    def username(self) -> str:
+        return self._username()
+
     async def run(
         self,
         cmd: list[str],

src/python/jw/pkg/lib/ec/Local.py

@@ -2,6 +2,8 @@
 
 import os, sys, subprocess, asyncio, pwd, grp, stat
 
+from functools import cache
+
 from ..ExecContext import ExecContext as Base
 from ..base import Result, StatResult
 
@@ -13,6 +15,10 @@ class Local(Base):
     def __init__(self, uri='local', *args, **kwargs) -> None:
         super().__init__(uri, *args, **kwargs)
 
+    @cache
+    def _username(self) -> str:
+        return pwd.getpwuid(os.getuid()).pw_name,
+
     async def _run(
         self,
         cmd: list[str],

src/python/jw/pkg/lib/ec/SSHClient.py

@@ -2,7 +2,7 @@
 
 from typing import Any
 
-import os, abc, sys
+import os, abc, sys, pwd
 from enum import Flag, auto
 
 from ..util import pretty_cmd
@@ -128,8 +128,9 @@ class SSHClient(ExecContext):
     def set_username(self, username: str) -> None:
         self.__username = username
 
-    @property
-    def username(self) -> str|None:
+    def _username(self) -> str:
+        if self.__username is None:
+            return pwd.getpwuid(os.getuid()).pw_name
         return self.__username
 
 def ssh_client(*args, type: str|list[str]|None=None, **kwargs) -> SSHClient: # export