Handle parent process not alive error in Sched class

- Import ParentNotAliveError in cli.py and sched.py
- Add ParentNotAliveError to __all__ in errors.py
- Implement ParentNotAliveError handling in Sched class methods
- Update ready function in cli.py to handle ParentNotAliveError

h3daemon/h3daemon/cli.py

@@ -9,7 +9,7 @@
 from typer import echo
 
 from h3daemon.connect import find_free_port
-from h3daemon.errors import CouldNotPossessError
+from h3daemon.errors import CouldNotPossessError, ParentNotAliveError
 from h3daemon.hmmfile import HMMFile
 from h3daemon.pidfile import create_pidfile
 from h3daemon.sched import Sched
@@ -116,12 +116,17 @@ def ready(hmmfile: Path, wait: bool = O_WAIT):
         if wait:
             wait_until(sched.is_ready)
 
-        if sched.is_ready():
-            typer.echo("Daemon is ready!")
-            raise typer.Exit(0)
-        else:
+        try:
+            if sched.is_ready():
+                typer.echo("Daemon is ready!")
+                raise typer.Exit(0)
+            else:
+                typer.echo("Daemon is NOT ready...")
+                raise typer.Exit(1)
+        except ParentNotAliveError:
             typer.echo("Daemon is NOT ready...")
             raise typer.Exit(1)
+
     except CouldNotPossessError as x:
         typer.echo(str(x))
         raise typer.Exit(1)

h3daemon/h3daemon/errors.py

@@ -1,4 +1,7 @@
-__all__ = ["ChildNotFoundError", "CouldNotPossessError"]
+__all__ = ["ParentNotAliveError", "ChildNotFoundError", "CouldNotPossessError"]
+
+
+class ParentNotAliveError(RuntimeError): ...
 
 
 class ChildNotFoundError(RuntimeError): ...

h3daemon/h3daemon/sched.py

@@ -10,7 +10,11 @@
 from pidlockfile import PIDLockFile
 
 from h3daemon.connect import find_free_port
-from h3daemon.errors import ChildNotFoundError, CouldNotPossessError
+from h3daemon.errors import (
+    ChildNotFoundError,
+    CouldNotPossessError,
+    ParentNotAliveError,
+)
 from h3daemon.hmmfile import HMMFile
 from h3daemon.master import Master
 from h3daemon.pidfile import create_pidfile
@@ -122,11 +126,13 @@ def run(self, hmmfile: str, cport: int, wport: int):
         try:
             master = spawn_master(hmmfile, cport, wport)
             worker = spawn_worker(wport)
+
             def shutdown(_):
                 try:
                     self.terminate_children(15)
                 except psutil.TimeoutExpired:
                     self.kill_children()
+
             psutil.wait_procs([master.process, worker.process], callback=shutdown)
         finally:
             try:
@@ -145,14 +151,27 @@ def kill_parent(self):
 
     def terminate_children(self, timeout: Union[float, None] = None):
         for x in self._proc.children():
-            x.terminate()
-            x.wait(timeout)
+            try:
+                x.terminate()
+                x.wait(timeout)
+            except psutil.NoSuchProcess:
+                pass
 
     def terminate_parent(self, timeout: Union[float, None] = None):
-        self._proc.terminate()
-        self._proc.wait(timeout)
+        try:
+            self._proc.terminate()
+            self._proc.wait(timeout)
+        except psutil.NoSuchProcess:
+            pass
+
+    def is_alive(self):
+        if not psutil.pid_exists(self._proc.pid):
+            return False
+        return self._proc.status() not in (psutil.STATUS_DEAD, psutil.STATUS_ZOMBIE)
 
     def is_ready(self):
+        if not self.is_alive():
+            raise ParentNotAliveError()
         try:
             master = self.master
             worker = self.worker