try all bootstrap nodes until successfully joined

src/Hash2Pub/Main.hs

@@ -17,12 +17,20 @@ main = do
     print serverSock
     -- currently no masking is necessary, as there is nothing to clean up
     cacheWriterThread <- forkIO $ cacheWriter thisNode
-    -- idea: list of bootstrapping nodes, try joining within a timeout
-    joinedState <- fediChordBootstrapJoin thisNode $ head . confBootstrapNodes $ conf
+    -- try joining the DHT using one of the provided bootstrapping nodes
+    let
+        tryJoining (bn:bns) = do
+            j <- fediChordBootstrapJoin thisNode bn
+            case j of
+              Left _ -> tryJoining bns
+              Right joined -> pure $ Right joined
+        tryJoining [] = pure $ Left "Exhausted all bootstrap points for joining."
+    joinedState <- tryJoining $ confBootstrapNodes conf
     -- stop main thread from terminating during development
     getChar
     pure ()
 
+
 readConfig :: IO FediChordConf
 readConfig = do
     confDomainString : ipString : portString : bootstrapHost : bootstrapPortString : _ <- getArgs