Remove bad daemon connections from the pool

This is necessary for long-running processes like hydra-queue-runner:
if a nix-daemon worker is killed, we need to stop reusing that
connection.

1 files changed, 5 insertions, 1 deletions

diff --git a/src/libstore/remote-store.cc b/src/libstore/remote-store.cc
index f6ec3fffb614..2f540c640e0b 100644
--- a/src/libstore/remote-store.cc
+++ b/src/libstore/remote-store.cc
@@ -40,7 +40,11 @@ template PathSet readStorePaths(Source & from);
 
 
 RemoteStore::RemoteStore(size_t maxConnections)
-    : connections(make_ref<Pool<Connection>>(maxConnections, [this]() { return openConnection(); }))
+    : connections(make_ref<Pool<Connection>>(
+            maxConnections,
+            [this]() { return openConnection(); },
+            [](const ref<Connection> & r) { return r->to.good() && r->from.good(); }
+            ))
 {
 }