dnsdist: expungeByName overwrites the output when called multiple times

[christofchen]

• Program: dnsdist
• Issue type: Bug report

Short description

When calling expungeByName multiple times on the same line, there is only one line of output (the last one)

Environment

• Operating system: Linux
• Software version: 1.7.x master
• Software source: github, self compiled

Steps to reproduce

preload the cache with entries for www.google.com and www.amazon.com, and expunge the records from the cache in one line:

getPool(""):getCache():expungeByName("www.google.com") getPool(""):getCache():expungeByName("www.amazon.com")
Expunged 1 records

Expected behaviour

Expunged 1 records
Expunged 1 records

Actual behaviour

Expunged 1 records (single line)

Other information

The output should be appended, not overwritten here:

diff --git a/pdns/dnsdistdist/dnsdist-lua-bindings-packetcache.cc b/pdns/dnsdistdist/dnsdist-lua-bindings-packetcache.cc
index fb560c568..184ff33c2 100644
--- a/pdns/dnsdistdist/dnsdist-lua-bindings-packetcache.cc
+++ b/pdns/dnsdistdist/dnsdist-lua-bindings-packetcache.cc
@@ -166,7 +166,7 @@ void setupLuaBindingsPacketCache(LuaContext& luaCtx, bool client)
                   qname = DNSName(boost::get<string>(dname));
                 }
                 if (cache) {
-                  g_outputBuffer="Expunged " + std::to_string(cache->expungeByName(qname, qtype ? *qtype : QType(QType::ANY).getCode(), suffixMatch ? *suffixMatch : false)) + " records\n";
+                  g_outputBuffer+="Expunged " + std::to_string(cache->expungeByName(qname, qtype ? *qtype : QType(QType::ANY).getCode(), suffixMatch ? *suffixMatch : false)) + " records\n";
                 }
     });
   luaCtx.registerFunction<void(std::shared_ptr<DNSDistPacketCache>::*)()const>("printStats", [](const std::shared_ptr<DNSDistPacketCache>& cache) {

[omoerbeek]

Merged