From 8575bc62098b71aaaef12a3970e2ed91b142c0b8 Mon Sep 17 00:00:00 2001
From: Sergi Delgado Segura <sergi.delgado.s@gmail.com>
Date: Wed, 29 Apr 2020 13:08:49 +0200
Subject: [PATCH] plugin - redesigns retrier using backoff

---
 watchtower-plugin/requirements.txt |  3 +-
 watchtower-plugin/retrier.py       | 99 ++++++++++++++++--------------
 2 files changed, 56 insertions(+), 46 deletions(-)

diff --git a/watchtower-plugin/requirements.txt b/watchtower-plugin/requirements.txt
index d1f1adf..84ba49d 100644
--- a/watchtower-plugin/requirements.txt
+++ b/watchtower-plugin/requirements.txt
@@ -3,4 +3,5 @@ requests
 coincurve
 cryptography==2.8
 pyzbase32
-plyvel
\ No newline at end of file
+plyvel
+backoff
\ No newline at end of file
diff --git a/watchtower-plugin/retrier.py b/watchtower-plugin/retrier.py
index d778c9e..a4cbf3d 100644
--- a/watchtower-plugin/retrier.py
+++ b/watchtower-plugin/retrier.py
@@ -1,59 +1,68 @@
+import backoff
+from threading import Thread
+
 from tower_info import TowerInfo
-from net.http import send_appointment
-from exceptions import TowerConnectionError, TowerResponseError
+from net.http import add_appointment
+
+
+MAX_RETRIES = None
+
+
+def on_backoff(details):
+    plugin = details.get("args")[1]
+    tower_id = details.get("args")[2]
+    plugin.log("Retry {} failed for tower {}, backing off".format(details.get("tries"), tower_id))
+
+
+def on_giveup(details):
+    plugin = details.get("args")[1]
+    tower_id = details.get("args")[2]
+    tower_info = details.get("args")[3]
+
+    plugin.log("Max retries reached, abandoning tower {}".format(tower_id))
+
+    tower_info.status = "unreachable"
+    plugin.wt_client.towers[tower_id]["status"] = "unreachable"
+    plugin.wt_client.db_manager.store_tower_record(tower_id, tower_info)
+
+
+def set_max_retries(max_retries):
+    global MAX_RETRIES
+    MAX_RETRIES = max_retries
+
+
+def max_retries():
+    return MAX_RETRIES
 
 
 class Retrier:
-    def __init__(self, retry_delta, max_retries, temp_unreachable_towers):
-        self.retry_delta = retry_delta
-        self.max_retries = max_retries
+    def __init__(self, max_retries, temp_unreachable_towers):
         self.temp_unreachable_towers = temp_unreachable_towers
-        self.retry_count = {}
+        set_max_retries(max_retries)
 
-    def do_retry(self, plugin):
+    def manage_retry(self, plugin):
         while True:
             tower_id = self.temp_unreachable_towers.get()
             tower_info = TowerInfo.from_dict(plugin.wt_client.db_manager.load_tower_record(tower_id))
 
-            try:
-                for appointment_dict, signature in plugin.wt_client.towers[tower_id]["pending_appointments"]:
-                    plugin.log("Retrying: sending appointment to {}".format(tower_id))
-                    response = send_appointment(tower_id, tower_info, appointment_dict, signature)
-                    plugin.log("Appointment accepted and signed by {})".format(tower_id))
-                    plugin.log("Remaining slots: {}".format(response.get("available_slots")))
+            Thread(target=self.do_retry, args=[plugin, tower_id, tower_info], daemon=True).start()
 
-                    tower_info.appointments[appointment_dict.get("locator")] = response.get("signature")
-                    tower_info.available_slots = response.get("available_slots")
+    @backoff.on_predicate(
+        backoff.expo,
+        lambda x: x == "temporarily unreachable",
+        max_tries=max_retries,
+        on_backoff=on_backoff,
+        on_giveup=on_giveup,
+    )
+    def do_retry(self, plugin, tower_id, tower_info):
+        for appointment_dict, signature in plugin.wt_client.towers[tower_id]["pending_appointments"]:
+            status = add_appointment(plugin, tower_id, tower_info, appointment_dict, signature)
 
-                    # Update memory and TowersDB
-                    tower_info.pending_appointments.remove([appointment_dict, signature])
-                    plugin.wt_client.db_manager.store_tower_record(tower_id, tower_info)
-                    plugin.wt_client.towers[tower_id] = tower_info.get_summary()
+            if status in ["reachable", "misbehaving"]:
+                tower_info.pending_appointments.remove([appointment_dict, signature])
 
-                    if tower_id in self.retry_count:
-                        self.retry_count.pop(tower_id)
+                # Update memory and TowersDB
+                plugin.wt_client.update_tower_state(tower_id, tower_info)
 
-                tower_info.status = "reachable"
-                plugin.wt_client.towers[tower_id]["status"] = "reachable"
-                plugin.wt_client.db_manager.store_tower_record(tower_id, tower_info)
-
-            except TowerConnectionError:
-                if tower_id not in self.retry_count:
-                    self.retry_count[tower_id] = 1
-                else:
-                    plugin.log("Retry {} failed for tower {}, backing off".format(self.retry_count[tower_id], tower_id))
-                    self.retry_count[tower_id] += 1
-
-                if self.retry_count[tower_id] <= self.max_retries:
-                    self.temp_unreachable_towers.put(tower_id)
-                else:
-                    plugin.log("Max retries reached, abandoning tower {}".format(tower_id))
-                    self.retry_count.pop(tower_id)
-
-                    tower_info.status = "unreachable"
-                    plugin.wt_client.towers[tower_id]["status"] = "unreachable"
-                    plugin.wt_client.db_manager.store_tower_record(tower_id, tower_info)
-
-            except TowerResponseError as e:
-                # FIXME: deal with tower errors, such as no available slots
-                plugin.log(str(e))
+            else:
+                return status