Add polling decorator and handle port edge cases

- Added `polling` decorator in `daemon.py` to `possess` and `wait_for_readiness` methods.
- Improved error handling for master and worker ports in `daemon.py`.
- Bumped package version from `0.16.5` to `0.16.6` in `pyproject.toml`.

The `polling` decorator improves process stability by ensuring certain conditions are met before proceeding. Enhanced error handling offers more robust port assignments, preventing runtime errors due to unexpected conditions. The version bump reflects these significant internal improvements. 🚀

h3daemon/h3daemon/daemon.py

@@ -11,6 +11,7 @@
 from h3daemon.errors import ChildNotFoundError, PIDNotFoundError
 from h3daemon.healthy import assert_peers_healthy
 from h3daemon.master import Master
+from h3daemon.polling import polling
 from h3daemon.port import find_free_port
 from h3daemon.worker import Worker
 
@@ -80,10 +81,12 @@ def spawn(cls, hmmfile: HMMFile, cport: int = 0, wport: int = 0):
         return cls(master, worker, None)
 
     @classmethod
+    @polling
     def possess(cls, pidfile: PIDLockFile):
         pid = pidfile.is_locked()
         if not pid:
             raise PIDNotFoundError("PID not in pidfile.")
+
         process = psutil.Process(pid)
         children = process.children()
 
@@ -109,6 +112,10 @@ def shutdown(self, force=False):
         if self._process is not None:
             shutdown(self._process, force)
 
+    @polling
+    def wait_for_readiness(self):
+        assert self.healthy
+
     def healthy(self) -> bool:
         try:
             if self._process:
@@ -121,7 +128,14 @@ def healthy(self) -> bool:
 
     def port(self) -> int:
         master_ports = set(self._master.local_listening_ports())
-        master_ports.remove(self._worker.remote_established_ports()[0])
+        worker_ports = self._worker.remote_established_ports()
+        if len(worker_ports) != 1:
+            raise RuntimeError("Expected one remote port. Worker might have died.")
+        master_ports.remove(worker_ports[0])
+        if len(master_ports) != 1:
+            raise RuntimeError(
+                "Expected one remaining master port. Master might have died."
+            )
         return int(list(master_ports)[0])
 
     def join(self):

h3daemon/pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "h3daemon"
-version = "0.16.5"
+version = "0.16.6"
 description = "HMMER server"
 authors = ["Danilo Horta <[email protected]>"]
 license = "MIT"