From: Mark Wooding <mdw@distorted.org.uk>
Date: Sat, 19 Jul 2014 16:22:37 +0000 (+0100)
Subject: peerdb/tripe-newpeers.in: Don't start duplicate resolver queries.
X-Git-Tag: 1.0.0pre16~23
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/tripe/commitdiff_plain/d8310a3a69671d7aeb6ea351a1f931f24a559a42

peerdb/tripe-newpeers.in: Don't start duplicate resolver queries.

Resolver queries are indexed by query domain name.  Previously, if we
find another place which wants the same name resolved, we'd overwrite
the existing query with the new one, which causes the old one to be
cancelled (despite it possibly having made progress).

(This also avoids tickling a bug in mLib's handling of aborted queries,
fixed separately.)
---

diff --git a/peerdb/tripe-newpeers.in b/peerdb/tripe-newpeers.in
index d7205845..aa9ccfcb 100644
--- a/peerdb/tripe-newpeers.in
+++ b/peerdb/tripe-newpeers.in
@@ -75,11 +75,12 @@ class BulkResolver (object):
 
   def prepare(me, host):
     """Prime the resolver to resolve the name HOST."""
-    me._resolvers[host] = M.SelResolveByName \
-                          (host,
-                           lambda name, alias, addr:
-                             me._resolved(host, addr[0]),
-                           lambda: me._resolved(host, None))
+    if host not in me._resolvers:
+      me._resolvers[host] = M.SelResolveByName \
+                            (host,
+                             lambda name, alias, addr:
+                               me._resolved(host, addr[0]),
+                             lambda: me._resolved(host, None))
 
   def run(me):
     """Run the background DNS resolver until it's finished."""