From 719f0142650ed4d9d4307b92af0520a03f6f584c Mon Sep 17 00:00:00 2001
From: Mark Veidemanis <m@zm.is>
Date: Thu, 11 Aug 2022 21:44:19 +0100
Subject: [PATCH] Implement best effort allocation

---
 modules/chankeep.py | 39 ++++++++++++++++++++++++---------------
 1 file changed, 24 insertions(+), 15 deletions(-)

diff --git a/modules/chankeep.py b/modules/chankeep.py
index 7f7ce14..89b8e60 100644
--- a/modules/chankeep.py
+++ b/modules/chankeep.py
@@ -5,7 +5,7 @@ from twisted.internet.threads import deferToThread
 
 import main
 import modules.provision
-from utils.logging.debug import debug
+from utils.logging.debug import debug, trace
 from utils.logging.log import error, log, warn
 
 
@@ -77,22 +77,31 @@ def emptyChanAllocate(net, flist, relay, new):
         chans_not_covered = toalloc - sum_free  # 2148 - 250 = 1898
         relays_needed = chans_not_covered / chanfree[1]  # 1898 / 250 = 7.592
         correction = ceil(relays_needed)
-        debug(
-            (
-                f"emptyChanAllocate() secondary allocation sum_free:{sum_free} "
-                f"chans_not_covered:{chans_not_covered} relays_needed:{relays_needed} "
-                f"correction:{correction}"
+        if main.config["ChanKeep"]["Provision"]:
+            debug(
+                (
+                    f"emptyChanAllocate() secondary allocation sum_free:{sum_free} "
+                    f"chans_not_covered:{chans_not_covered} relays_needed:{relays_needed} "
+                    f"correction:{correction}"
+                )
             )
-        )
-        debug(
-            (
-                f"emptyChanAllocate() not enough free channels: toalloc:{toalloc} "
-                f"free:{chanfree[0]} chanlimit:{chanfree[1]} correction:{correction}"
+            debug(
+                (
+                    f"emptyChanAllocate() not enough free channels: toalloc:{toalloc} "
+                    f"free:{chanfree[0]} chanlimit:{chanfree[1]} correction:{correction}"
+                )
             )
-        )
-        warn("Ran out of channel spaces, provisioning additional %i relays for %s" % (correction, net))
-        modules.provision.provisionMultipleRelays(net, correction)
-        return False
+            warn("Ran out of channel spaces, provisioning additional %i relays for %s" % (correction, net))
+            modules.provision.provisionMultipleRelays(net, correction)
+            return False
+        else:
+            # We don't have enough spaces and we can't add any.
+            # Let's do the best we can in the circumstances.
+            debug(f"emptyChanAllocate() cannot create additional relays for {net}")
+            debug(f"emptyChanAllocate() {chans_not_covered} channels cannot be covered")
+            flist = flist[:sum_free]
+            debug(f"emptyChanAllocate() flist truncated to {sum_free}, length nis now {len(flist)}")
+            trace(f"emptyChanAllocate() best effort allocation: {flist}")
     for i in chanfree[0].keys():
         for x in range(chanfree[0][i]):
             if not len(flist):