allow killing and signalling entire process groups

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## 1.2 -
 
+*   added `.kill_group()` and `.signal_group()` methods for better process control [#237](https://github.com/amoffat/sh/pull/237)
 *   added `new_session` special keyword argument for controlling spawned process session [#266](https://github.com/amoffat/sh/issues/266)
 *   bugfix better handling for EINTR on system calls [#292](https://github.com/amoffat/sh/pull/292)
 *   bugfix where with-contexts were not threadsafe [#247](https://github.com/amoffat/sh/issues/195)

sh.py

@@ -503,6 +503,8 @@ class RunningCommand(object):
         "signal",
         "terminate",
         "kill",
+        "kill_group",
+        "signal_group",
         "pid",
         "sid",
         "pgid",
@@ -1763,10 +1765,17 @@ def get_sid(self):
         self.sid is the session id at launch """
         return os.getsid(self.pid)
 
+    def signal_group(self, sig):
+        self.log.debug("sending signal %d to group", sig)
+        os.killpg(self.get_pgid(), sig)
+
     def signal(self, sig):
         self.log.debug("sending signal %d", sig)
         os.kill(self.pid, sig)
 
+    def kill_group(self):
+        self.log.debug("killing group")
+        self.signal_group(signal.SIGKILL)
 
     def kill(self):
         self.log.debug("killing")

test.py

@@ -1736,6 +1736,66 @@ def throw_terminate_signal():
         self.assertRaises(SignalException_15, throw_terminate_signal)
 
 
+    def test_signal_group(self):
+        child = create_tmp_test("""
+import time
+time.sleep(3)
+""")
+
+        parent = create_tmp_test("""
+import sh
+p = sh.python("{child_file}", _bg=True, _new_session=False)
+print(p.pid)
+print(p.process.pgid)
+p.wait()
+""", child_file=child.name)
+
+        def launch():
+            p = python(parent.name, _bg=True, _iter=True)
+            child_pid = int(next(p).strip())
+            child_pgid = int(next(p).strip())
+            parent_pid = p.pid
+            parent_pgid = p.process.pgid
+
+            return p, child_pid, child_pgid, parent_pid, parent_pgid
+
+        def assert_alive(pid):
+            os.kill(pid, 0)
+
+        def assert_dead(pid):
+            self.assert_oserror(errno.ESRCH, os.kill, pid, 0)
+
+
+        # first let's prove that calling regular SIGKILL on the parent does
+        # nothing to the child, since the child was launched in the same process
+        # group (_new_session=False) and the parent is not a controlling process
+        p, child_pid, child_pgid, parent_pid, parent_pgid = launch()
+
+        assert_alive(parent_pid)
+        assert_alive(child_pid)
+
+        p.kill()
+        time.sleep(0.1)
+        assert_dead(parent_pid)
+        assert_alive(child_pid)
+
+        self.assertRaises(sh.SignalException_SIGKILL, p.wait)
+        assert_dead(child_pid)
+
+
+        # now let's prove that killing the process group kills both the parent
+        # and the child
+        p, child_pid, child_pgid, parent_pid, parent_pgid = launch()
+
+        assert_alive(parent_pid)
+        assert_alive(child_pid)
+
+        p.kill_group()
+        time.sleep(0.1)
+        assert_dead(parent_pid)
+        assert_dead(child_pid)
+
+
     def test_file_output_isnt_buffered(self):
         # https://github.com/amoffat/sh/issues/147