build-remote: Fix fallback to other machines when connecting fails

Opening an SSHStore or LegacySSHStore does not actually establish a
connection, so the try/catch block here did nothing. Added a
Store::connect() method to test whether a connection can be
established.

1 files changed, 4 insertions, 0 deletions

diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
index 8ca3f4b27d..b06f5d86a9 100644
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@@ -582,6 +582,10 @@ public:
         state.lock()->pathInfoCache.clear();
     }
 
+    /* Establish a connection to the store, for store types that have
+       a notion of connection. Otherwise this is a no-op. */
+    virtual void connect() { };
+
 protected:
 
     Stats stats;