From 3746e5ae0f68ac0b24ea439bd6bf484bc1de30ee Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Magalh=C3=A3es?= <joamag@gmail.com>
Date: Fri, 5 Oct 2018 18:41:46 +0100
Subject: [PATCH] better peer update structure

---
 src/appier/base.py | 135 ++++++++++++++++++++++++++++++---------------
 1 file changed, 91 insertions(+), 44 deletions(-)

diff --git a/src/appier/base.py b/src/appier/base.py
index 78a3c34b..3d0beb08 100644
--- a/src/appier/base.py
+++ b/src/appier/base.py
@@ -4335,52 +4335,14 @@ def _load_supervisor(self):
 
         # runs the initial bind operations for both the update and the
         # (new) peer events responsible for the global status consistency
-        self.bind_bus("update_peers", self.on_discover_peers)
-        self.bind_bus("peer", self.on_peer)
+        self.bind_bus("update_peers", self._on_update_peers)
+        self.bind_bus("peer", self._on_peer)
 
     def _unload_supervisor(self):
-        self.unbind_bus("update_peers", self.on_discover_peers)
-        self.unbind_bus("peer", self.on_peer)
-
-    def _schedule_peers(self, timeout = 60.0):
-        if not self.get_bus_d(): return
-        self._cleanup_peers(timeout = timeout * 2)
-        self.trigger_bus("update_peers")
-        self.schedule(
-            self._schedule_peers,
-            timeout = timeout,
-            kwargs = dict(timeout = timeout)
-        )
-
-    def _cleanup_peers(self, timeout = 120.0):
-        current = time.time()
-        target = current - timeout
-        for uid, peer in legacy.items(self._peers):
-            if peer["ping"] > target: continue
-            del self._peers[uid]
-
-    def on_discover_peers(self):
-        self.trigger_bus(
-            "peer",
-            data = dict(
-                uid = self.uid,
-                name = self.name,
-                name_b = self.name_b,
-                name_i = self.name_i,
-                info_dict = self.info_dict()
-            )
-        )
-
-    def on_peer(self, data = None):
-        if not data: return
-        uid = data.get("uid", None)
-        if not uid: return
-        if uid == self.uid: return
-        peer = self._peers.get("uid", None)
-        if not peer: peer = dict()
-        peer["data"] = data
-        peer["ping"] = time.time()
-        self._peers[uid] = peer
+        # runs the unbind operation for the global events related with the
+        # peer updating operations (no longer needed)
+        self.unbind_bus("update_peers", self._on_update_peers)
+        self.unbind_bus("peer", self._on_peer)
 
     def _add_handlers(self, logger):
         for handler in self.handlers:
@@ -4602,7 +4564,92 @@ def _set_global(self):
     def _set_variables(self):
         self.description = self._description()
 
+    def _schedule_peers(self, timeout = 60.0):
+        """
+        Runs the scheduling of the peers discovery operation for
+        the current tick and at the end of its execution schedules
+        a new one according to the provided timeout.
+
+        :type timeout: float
+        :param timeout: The number of seconds until the next peers
+        scheduling operation should be performed.
+        """
+
+        if not self.get_bus_d(): return
+        self._refresh_peers(timeout = timeout * 2)
+        self.trigger_bus("update_peers")
+        self.schedule(
+            self._schedule_peers,
+            timeout = timeout,
+            kwargs = dict(timeout = timeout)
+        )
+
+    def _refresh_peers(self, timeout = 120.0):
+        """
+        Runs the house keeping operation on the peers structure so
+        that for instance old peers are removed once a certain timeout
+        threshold is reached.
+
+        It should be considered a garbage collection operation.
+
+        :type timeout: float
+        :param timeout: The maximum number of seconds waiting for a "ping"
+        operation from a peer until it should be considered expired.
+        """
+
+        current = time.time()
+        target = current - timeout
+        for uid, peer in legacy.items(self._peers):
+            if peer["ping"] > target: continue
+            del self._peers[uid]
+
+    def _on_update_peers(self):
+        """
+        Callback method triggered when a request for an update operation
+        about the peers on the bus is performed.
+
+        Should send the information on the current peer to the bus.
+        """
+
+        self.trigger_bus(
+            "peer",
+            data = dict(
+                uid = self.uid,
+                name = self.name,
+                name_b = self.name_b,
+                name_i = self.name_i,
+                info_dict = self.info_dict()
+            )
+        )
+
+    def _on_peer(self, data = None):
+        """
+        Callback method to be called when the information regarding
+        a new peer is received on the currently (shared) bus.
+
+        :type data: Dictionary
+        :param data: The map contain the detailed information on the
+        peer (it should have been send on the "wire").
+        """
+
+        if not data: return
+        uid = data.get("uid", None)
+        if not uid: return
+        if uid == self.uid: return
+        peer = self._peers.get("uid", None)
+        if not peer: peer = dict()
+        peer["data"] = data
+        peer["ping"] = time.time()
+        self._peers[uid] = peer
+
     def _apply_config(self):
+        """
+        Applies a series of configuration related values to the current
+        instance should be able to normalized many of its values.
+
+        Some of the values are constructed by appending multiple values.
+        """
+
         self.instance = config.conf("INSTANCE", None)
         self.instance = config.conf("PROFILE", self.instance)
         self.name = config.conf("NAME", self.name)