dynamic burst management. makes downloading better

commit 7781e1df1dd258fabfb5d6dd2f9748f4c4d5985a
Author: Dmitry Zuikov <dzuikov@gmail.com>
Date:   Sat Feb 4 11:14:55 2023 +0300

    burst tune

commit 4e837691a5bd7fcda1d0bc8b89c5a377aa18ae30
Author: Dmitry Zuikov <dzuikov@gmail.com>
Date:   Sat Feb 4 11:06:09 2023 +0300

    dynamic-burst-management-wip

commit 575ba7bb6a8952ad79021420c488ffd4ef84f413
Author: Dmitry Zuikov <dzuikov@gmail.com>
Date:   Sat Feb 4 11:01:14 2023 +0300

    dynamic-burst-management-wip

commit 5517df31d790c130e65cf6eb0049dabdd3d627da
Author: Dmitry Zuikov <dzuikov@gmail.com>
Date:   Sat Feb 4 10:18:53 2023 +0300

    dynamic-burst-management-wip

commit 4c5c0b580d9a8c81e4133cc61a15d42b737e2b3c
Author: Dmitry Zuikov <dzuikov@gmail.com>
Date:   Sat Feb 4 09:29:45 2023 +0300

    wip

commit 0132b55be40939e321dc9adc8f4f6176c98c46dc
Author: Dmitry Zuikov <dzuikov@gmail.com>
Date:   Sat Feb 4 09:14:47 2023 +0300

    wip

commit 0bb90781e857076bb20a2e34da8f7edaa63f7815
Author: Dmitry Zuikov <dzuikov@gmail.com>
Date:   Fri Feb 3 14:50:49 2023 +0300

    wip

commit 67befe2af5f7c4139eee5f018a26b78e95aa6cb3
Author: Dmitry Zuikov <dzuikov@gmail.com>
Date:   Fri Feb 3 13:51:57 2023 +0300

    wip

commit d6d5769e032245a130dd4508a2780654b046dceb
Author: Dmitry Zuikov <dzuikov@gmail.com>
Date:   Fri Feb 3 12:48:49 2023 +0300

    wip

commit c78bb51f10c14bea483bfa235aa464d6b857263d
Author: Dmitry Zuikov <dzuikov@gmail.com>
Date:   Fri Feb 3 12:46:03 2023 +0300

    wip

README.md

@@ -0,0 +1,12 @@
+
+
+
+## How to launch a peer
+
+Example:
+```
+
+hbs2-peer run -p .peers/1  -k .peers/1/key -l addr:port -r rpcaddr:rpcport
+
+```
+

hbs2-core/lib/HBS2/Defaults.hs

@@ -13,7 +13,10 @@ defMessageQueueSize :: Integral a => a
 defMessageQueueSize = 65536
 
 defBurst :: Integral a => a
-defBurst = 16
+defBurst = 4
+
+defBurstMax :: Integral a => a
+defBurstMax = 256
 
 -- defChunkSize :: Integer
 defChunkSize :: Integral a => a
@@ -47,6 +50,9 @@ defCookieTimeoutSec = 1200
 defCookieTimeout :: TimeSpec
 defCookieTimeout = toTimeSpec defCookieTimeoutSec
 
+defBlockWipTimeout :: TimeSpec
+defBlockWipTimeout = toTimeSpec defCookieTimeoutSec
+
 defBlockInfoTimeout :: Timeout 'Seconds
 defBlockInfoTimeout = 2
 

hbs2-core/lib/HBS2/Net/Proto/BlockInfo.hs

@@ -44,7 +44,6 @@ blockSizeProto getBlockSize evHasBlock =
       emit @e (BlockSizeEventKey h) (BlockSizeEvent (that, h, sz))
       evHasBlock ( that, h, Just sz )
 
-
 newtype instance SessionKey e (BlockInfo e) =
   BlockSizeKey (Hash HbSync)
   deriving stock (Typeable,Eq,Show)

hbs2-core/lib/HBS2/System/Logger/Simple.hs

@@ -12,7 +12,7 @@ module HBS2.System.Logger.Simple
   , notice
   , info
   , setLogging
-  , asIs
+  , defLog
   , loggerTr
   , module HBS2.System.Logger.Simple.Class
   ) where
@@ -39,8 +39,8 @@ data LoggerEntry =
 
 makeLenses 'LoggerEntry
 
-asIs :: a -> a
+defLog :: a -> a
-asIs = id
+defLog = id
 
 {-# OPTIONS_GHC -fno-cse #-}
 {-# NOINLINE loggers #-}

hbs2-peer/app/BlockDownload.hs

@@ -21,18 +21,22 @@ import HBS2.System.Logger.Simple
 
 import PeerInfo
 
-import Data.Foldable hiding (find)
 import Control.Concurrent.Async
 import Control.Concurrent.STM
 import Control.Monad.Reader
 import Control.Monad.Trans.Maybe
 import Data.ByteString.Lazy (ByteString)
+import Data.Cache (Cache)
+import Data.Cache qualified as Cache
+import Data.Foldable hiding (find)
 import Data.HashMap.Strict (HashMap)
 import Data.HashMap.Strict qualified as HashMap
 import Data.IntMap (IntMap)
 import Data.IntMap qualified as IntMap
 import Data.IntSet qualified as IntSet
 import Data.Maybe
+import Data.Set qualified as Set
+import Data.Set (Set)
 import Lens.Micro.Platform
 import Prettyprinter
 import System.Random.Shuffle
@@ -50,7 +54,6 @@ calcBursts bu pieces = go seed
     go [x] = [x]
     go [] = []
 
-
 data BlockDownload =
   BlockDownload
   { _sBlockHash      :: Hash HbSync
@@ -74,11 +77,16 @@ newtype instance SessionKey e (BlockChunks e) =
   deriving stock (Generic,Typeable)
 
 
+-- data MyBlkInfo e =
+--   MyBlkInfo (Peer e) Integer
+  -- deriving stock (Eq,Ord)
 
 data DownloadEnv e =
   DownloadEnv
   { _downloadQ   :: TQueue (Hash HbSync)
   , _peerBusy    :: TVar   (HashMap (Peer e) ())
+  , _blockPeers  :: TVar   (HashMap (Hash HbSync) (HashMap (Peer e) Integer) )
+  , _blockWip    :: Cache  (Hash HbSync) ()
   }
 
 makeLenses 'DownloadEnv
@@ -90,6 +98,8 @@ newDownloadEnv :: (MonadIO m, MyPeer e) => m (DownloadEnv e)
 newDownloadEnv = liftIO do
   DownloadEnv <$> newTQueueIO
               <*> newTVarIO mempty
+              <*> newTVarIO mempty
+              <*> Cache.newCache (Just defBlockWipTimeout)
 
 newtype BlockDownloadM e m a =
   BlockDownloadM { fromBlockDownloadM :: ReaderT (DownloadEnv e) m a }
@@ -110,9 +120,16 @@ withDownload e m = runReaderT ( fromBlockDownloadM m ) e
 addDownload :: MonadIO m => Hash HbSync -> BlockDownloadM e m ()
 addDownload h = do
   q <- asks (view downloadQ)
-  liftIO $ atomically $ writeTQueue q h
+  wip <- asks (view blockWip)
-  -- debug $ "addDownload" <+> pretty h
+
-  -- pause ( 0.25 :: Timeout 'Seconds )
+  liftIO do
+    atomically $ writeTQueue q h
+    Cache.insert wip h ()
+
+removeFromWip :: MonadIO m => Hash HbSync -> BlockDownloadM e m ()
+removeFromWip h = do
+  wip <- asks (view blockWip)
+  liftIO $ Cache.delete wip h
 
 withFreePeer :: (MyPeer e, MonadIO m)
              => Peer e
@@ -134,11 +151,46 @@ withFreePeer p n m = do
       liftIO $ atomically $ modifyTVar busy $ HashMap.delete p
       pure r
 
+-- NOTE: dangerous! if called in
+--       wrong place/wrong time,
+--       if may cause a drastical
+--       download speed degradation
+
+dismissPeer  :: (MyPeer e, MonadIO m)
+             => Peer e
+             -> BlockDownloadM e m ()
+dismissPeer p = do
+  busy <- asks (view peerBusy)
+  liftIO $ atomically $ modifyTVar busy $ HashMap.delete p
+
 getBlockForDownload :: MonadIO m => BlockDownloadM e m (Hash HbSync)
 getBlockForDownload = do
   q <- asks (view downloadQ)
   liftIO $ atomically $ readTQueue q
 
+addBlockInfo :: (MonadIO m, MyPeer e)
+             => Peer e
+             -> Hash HbSync
+             -> Integer
+             -> BlockDownloadM e m ()
+
+addBlockInfo pip h size = do
+  -- debug $ "addBlockInfo" <+> pretty h <+> pretty pip <+> pretty size
+  tv <- asks (view blockPeers)
+  let mySize = HashMap.singleton pip size
+  liftIO $ atomically
+         $ modifyTVar tv (HashMap.insertWith (<>) h mySize)
+
+getPeersForBlock :: (MonadIO m, MyPeer e)
+                => Hash HbSync
+                -> BlockDownloadM e m [(Peer e, Integer)]
+
+getPeersForBlock h = do
+  tv <- asks (view blockPeers)
+  liftIO $ readTVarIO tv <&> foldMap HashMap.toList
+                                            . maybeToList
+                                            . HashMap.lookup h
+
 processBlock :: forall e m . ( MonadIO m
                              , HasStorage m
                              , Block ByteString ~ ByteString
@@ -152,6 +204,10 @@ processBlock h = do
 
    bt <- liftIO $ getBlock sto h <&> fmap (tryDetect h)
 
+   -- FIXME:  если блок нашёлся, то удаляем его из wip
+
+   when (isJust bt) (removeFromWip h)
+
    case bt of
      Nothing -> addDownload h
 
@@ -169,14 +225,28 @@ processBlock h = do
 
            if here then do
              debug $ "block" <+> pretty blk <+> "is already here"
+             processBlock blk -- NOTE: хуже не стало
+             -- FIXME: processBlock h
+             --        может быть, в этом причина того,
+             --        что мы периодически не докачиваем?
+             --
+             --        может быть, нужно рекурсировать, что бы
+             --        посмотреть, что это за блок и что у нас
+             --        из него есть?
+
              pure () -- we don't need to recurse, cause walkMerkle is recursing for us
 
-           else
+           else do
               addDownload blk
 
+
      Just (Blob{}) -> do
        pure ()
 
+-- NOTE: if peer does not have a block, it may
+--       cause to an unpleasant timeouts
+--       So make sure that this peer really answered to
+--       GetBlockSize request
 
 downloadFromWithPeer :: forall e m . ( MyPeer e
                                      , MonadIO m
@@ -193,33 +263,15 @@ downloadFromWithPeer :: forall e m . ( MyPeer e
                                      , HasStorage m
                                      )
                      => Peer e
+                     -> Integer
                      -> Hash HbSync
                      -> BlockDownloadM e m ()
-downloadFromWithPeer peer h = do
+downloadFromWithPeer peer thisBkSize h = do
-
 
   npi <- newPeerInfo
   pinfo <- lift $ fetch True npi (PeerInfoKey peer) id
 
-  waitSize <- liftIO $ newTBQueueIO 1
+  sto <- lift getStorage
-
-  lift $ do
-    subscribe @e (BlockSizeEventKey h) $ \(BlockSizeEvent (p1,hx,s)) -> do
-      when ( p1 == peer ) $ do
-        liftIO $ atomically $ writeTBQueue waitSize s
-
-    request @e peer (GetBlockSize @e h)
-
-  esize <- liftIO $ race ( pause defBlockInfoTimeout  ) do -- FIXME: block size wait time
-            atomically $ readTBQueue waitSize
-
-  let mbSize = either (const Nothing) Just esize
-
-  sto <- lift $ getStorage
-
-  case mbSize of
-    Nothing -> void $ addDownload h
-    Just thisBkSize  -> do
 
   coo <- genCookie (peer,h)
   let key = DownloadSessionKey (peer, coo)
@@ -267,17 +319,21 @@ downloadFromWithPeer peer h = do
                                                           $ readTQueue chuQ )
 
                                            )
-              when (null catched) $ do
+        if not (null catched) then do
+          liftIO $ atomically $ modifyTVar (view peerDownloaded pinfo) (+chunksN)
+        else do
 
-                -- nerfing peer burst size.
+            liftIO $ atomically $ modifyTVar (view peerErrors pinfo) succ
-                -- FIXME: we need a thread that will be reset them again
+            updatePeerInfo pinfo
 
-                newBurst <- liftIO $ atomically
+            newBurst <- liftIO $ readTVarIO burstSizeT
-                                   $ stateTVar burstSizeT $ \c -> let v = max 1 (c `div` 2)
+
-                                                                  in (v,v)
+            liftIO $ atomically $ modifyTVar (view peerDownloaded pinfo) (+chunksN)
 
             let chuchu = calcBursts newBurst [ i + n | n <- [0 .. chunksN] ]
 
+            liftIO $ atomically $ modifyTVar (view peerErrors pinfo) succ
+
             debug $ "new burst: " <+> pretty newBurst
             debug $ "missed chunks for request" <+> pretty (i,chunksN)
 
@@ -323,6 +379,43 @@ downloadFromWithPeer peer h = do
 instance HasPeerLocator e m => HasPeerLocator e (BlockDownloadM e m) where
   getPeerLocator = lift getPeerLocator
 
+
+updatePeerInfo :: MonadIO m => PeerInfo e -> m ()
+updatePeerInfo pinfo = do
+
+  t1 <- liftIO $ getTime MonotonicCoarse
+
+  void $ liftIO $ atomically $ do
+
+          bu        <- readTVar (view peerBurst pinfo)
+          errs      <- readTVar (view peerErrors pinfo)
+          errsLast  <- readTVar (view peerErrorsLast pinfo)
+          t0        <- readTVar (view peerLastWatched pinfo)
+          down      <- readTVar (view peerDownloaded pinfo)
+          downLast  <- readTVar (view peerDownloadedLast pinfo)
+
+          let dE  =  realToFrac $ max 0 (errs - errsLast)
+          let dT  =  realToFrac (max 1 (toNanoSecs t1 - toNanoSecs t0)) / 1e9
+
+          let eps = floor (dE / dT)
+
+          let bu1 = if down - downLast > 0 then
+                      max 1 $ min defBurstMax
+                              $ ceiling
+                              $ if eps == 0 then
+                                   realToFrac bu * 1.05 -- FIXME: to defaults
+                                 else
+                                   realToFrac bu * 0.65
+                    else
+                      max defBurst $ ceiling (realToFrac bu * 0.65)
+
+          writeTVar (view peerErrorsLast pinfo) errs
+          writeTVar (view peerLastWatched pinfo) t1
+          writeTVar (view peerErrorsPerSec pinfo) eps
+          writeTVar (view peerBurst pinfo) bu1
+          writeTVar (view peerDownloadedLast pinfo) down
+
+
 blockDownloadLoop :: forall e  m . ( m ~ PeerM e IO
                                    ,  MonadIO m
                                    , Request e (BlockInfo e) m
@@ -354,6 +447,18 @@ blockDownloadLoop env0 = do
 
   pl <- getPeerLocator @e
 
+
+  void $ liftIO $ async $ forever $ withPeerM e do
+    pause @'Seconds 0.5
+
+    pee <- knownPeers @e pl
+    npi <- newPeerInfo
+
+
+    for_ pee $ \p -> do
+      pinfo <- fetch True npi (PeerInfoKey p) id
+      updatePeerInfo pinfo
+
   -- TODO: peer info loop
   void $ liftIO $ async $ forever $ withPeerM e $ do
     pause @'Seconds 20
@@ -366,16 +471,39 @@ blockDownloadLoop env0 = do
     for_ pee $ \p -> do
       pinfo <- fetch True npi (PeerInfoKey p) id
       burst  <- liftIO $ readTVarIO (view peerBurst pinfo)
+      errors <- liftIO $ readTVarIO (view peerErrorsPerSec pinfo)
       debug $ "peer" <+> pretty p <+> "burst: " <+> pretty burst
+                                  <+> "errors:" <+> pretty errors
       pure ()
 
+  void $ liftIO $ async $ forever $ withPeerM e $ withDownload env0 do
+    pause @'Seconds 5 -- FIXME: put to defaults
+                      --        we need to show download stats
+
+    tinfo <- asks (view blockPeers)
+    binfo <- liftIO $ readTVarIO tinfo
+    wip  <- asks (view blockWip)
+
+    liftIO $ Cache.purgeExpired wip
+
+    aliveWip <- Set.fromList <$> liftIO (Cache.keys wip)
+
+    let alive = HashMap.fromList [ (h,i)
+                                   | (h,i) <- HashMap.toList binfo
+                                   , Set.member h aliveWip
+                                 ]
+
+    liftIO $ atomically $ writeTVar tinfo alive
+
+    debug $ "maintain blocks wip" <+> pretty (Set.size aliveWip)
+
   withDownload env0 do
 
     env <- ask
 
     let again h = do
-          debug $ "block fucked: " <+> pretty h
+          -- debug $ "retrying block: " <+> pretty h
-          withPeerM e $ withDownload env (processBlock h)
+          withPeerM e $ withDownload env (addDownload h)
 
     mapM_ processBlock blks
 
@@ -387,13 +515,46 @@ blockDownloadLoop env0 = do
 
       unless here do
 
-        void $ runMaybeT $ do
+        peers <- getPeersForBlock h
-          p  <- MaybeT $ knownPeers @e pl >>= liftIO . shuffleM <&> headMay
 
-          liftIO $ race ( pause defBlockWaitMax >> again h ) do
+        when (null peers) $ do
-            withPeerM e $ withDownload env $ do -- NOTE: really crazy shit
+
-              withFreePeer p (processBlock h >> pause (0.1 :: Timeout 'Seconds)) do
+          lift do -- in PeerM
-                downloadFromWithPeer p h
+            subscribe (BlockSizeEventKey h) $ \(BlockSizeEvent (p1,hx,s)) -> do
+              withDownload env (addBlockInfo p1 hx s)
+
+            pips <- knownPeers @e pl
+            for_ pips $ \pip -> request pip (GetBlockSize @e h)
+
+        p  <- knownPeers @e pl >>= liftIO . shuffleM
+
+          -- FIXME: нам не повезло с пиром => сидим ждём defBlockWaitMax и скачивание
+          --        простаивает.
+          --
+          --        Нужно: сначала запросить всех у кого есть блок.
+          --        Потом выбрать победителей и попытаться скачать
+          --        у них, запомнив размер в кэше.
+          --
+          --        Когда находим блоки -- то сразу же асинхронно запрашиваем
+          --        размеры, что бы по приходу сюда они уже были
+
+
+        -- debug $ "known peers" <+> pretty p
+        -- debug $ "peers/blocks" <+> pretty peers
+
+        p0 <- headMay <$> liftIO (shuffleM peers) -- FIXME: random choice to work faster
+
+        let withAllShit f = withPeerM e $ withDownload env f
+
+        maybe1 p0 (again h) $ \(p1,size) -> do
+            withFreePeer p1 (again h) $
+              liftIO do
+                  re <- race ( pause defBlockWaitMax ) $
+                          withAllShit $ downloadFromWithPeer p1 size h
+
+                  case re of
+                    Left{}  -> withAllShit (again h)
+                    Right{} -> withAllShit (processBlock h)
 
       next
 

hbs2-peer/app/PeerInfo.hs

@@ -11,9 +11,15 @@ import Lens.Micro.Platform
 import Control.Concurrent.STM.TVar
 
 
-newtype PeerInfo e =
+data PeerInfo e =
   PeerInfo
   { _peerBurst          :: TVar Int
+  , _peerErrors         :: TVar Int
+  , _peerErrorsLast     :: TVar Int
+  , _peerErrorsPerSec   :: TVar Int
+  , _peerLastWatched    :: TVar TimeSpec
+  , _peerDownloaded     :: TVar Int
+  , _peerDownloadedLast :: TVar Int
   }
   deriving stock (Generic,Typeable)
 
@@ -23,7 +29,12 @@ makeLenses 'PeerInfo
 newPeerInfo :: MonadIO m => m (PeerInfo e)
 newPeerInfo = liftIO do
   PeerInfo <$> newTVarIO defBurst
-
+           <*> newTVarIO 0
+           <*> newTVarIO 0
+           <*> newTVarIO 0
+           <*> newTVarIO 0
+           <*> newTVarIO 0
+           <*> newTVarIO 0
 
 type instance SessionData e (PeerInfo e) = PeerInfo e
 

hbs2-peer/app/PeerMain.hs

@@ -65,6 +65,7 @@ data RPCCommand =
   | ANNOUNCE (Hash HbSync)
   | PING (PeerAddr UDP)
   | CHECK PeerNonce (PeerAddr UDP) (Hash HbSync)
+  | FETCH (Hash HbSync)
 
 data PeerOpts =
   PeerOpts
@@ -86,10 +87,10 @@ main = do
   sodiumInit
 
   setLogging @DEBUG  (set loggerTr ("[debug] " <>))
-  setLogging @INFO   asIs
+  setLogging @INFO   defLog
-  setLogging @ERROR  asIs
+  setLogging @ERROR  defLog
-  setLogging @WARN   asIs
+  setLogging @WARN   defLog
-  setLogging @NOTICE asIs
+  setLogging @NOTICE defLog
 
   withSimpleLogger runCLI
 
@@ -106,6 +107,7 @@ runCLI = join . customExecParser (prefs showHelpOnError) $
                         <> command "poke"      (info pPoke (progDesc "poke peer by rpc"))
                         <> command "announce"  (info pAnnounce (progDesc "announce block"))
                         <> command "ping"      (info pPing (progDesc "ping another peer"))
+                        <> command "fetch"     (info pFetch (progDesc "fetch block"))
                         )
 
     common = do
@@ -145,6 +147,11 @@ runCLI = join . customExecParser (prefs showHelpOnError) $
       h   <- strArgument ( metavar "HASH" )
       pure $ runRpcCommand rpc (ANNOUNCE h)
 
+    pFetch = do
+      rpc <- pRpcCommon
+      h   <- strArgument ( metavar "HASH" )
+      pure $ runRpcCommand rpc (FETCH h)
+
     pPing = do
       rpc <- pRpcCommon
       h   <- strArgument ( metavar "ADDR" )
@@ -289,6 +296,12 @@ runPeer opts = Exception.handle myException $ do
                 debug $ "Got authorized peer!" <+> pretty p
                                                <+> pretty (AsBase58 (view peerSignKey d))
 
+
+              void $ liftIO $ async $ withPeerM env do
+                pause @'Seconds 1
+                debug "sending first peer announce"
+                request localMulticast (PeerAnnounce @UDP pnonce)
+
               void $ liftIO $ async $ withPeerM env $ forever $ do
                 pause defPeerAnnounceTime -- FIXME: setting!
                 debug "sending local peer announce"
@@ -339,6 +352,8 @@ runPeer opts = Exception.handle myException $ do
                                   withDownload denv $ do
                                     processBlock h
 
+                          _ -> pure ()
+
 
               me <- liftIO $ async $ withPeerM env $ do
                 runProto @UDP
@@ -359,10 +374,16 @@ runPeer opts = Exception.handle myException $ do
   let pingAction pa = do
         liftIO $ atomically $ writeTQueue rpcQ (PING pa)
 
+  let fetchAction h = do
+        debug  $ "fetchAction" <+> pretty h
+        liftIO $ withPeerM penv
+               $ withDownload denv (processBlock h)
+
   let arpc = RpcAdapter pokeAction
                         dontHandle
                         annAction
                         pingAction
+                        fetchAction
 
   rpc <- async $ runRPC udp1 do
                    runProto @UDP
@@ -408,12 +429,6 @@ emitToPeer env k e = liftIO $ withPeerM env (emit k e)
 withRPC :: String -> RPC UDP -> IO ()
 withRPC saddr cmd = withSimpleLogger do
 
-  setLogging @DEBUG  asIs
-  setLogging @INFO   asIs
-  setLogging @ERROR  asIs
-  setLogging @WARN   asIs
-  setLogging @NOTICE asIs
-
   as <- parseAddr (fromString saddr) <&> fmap (PeerUDP . addrAddress)
   let rpc' = headMay $ L.sortBy (compare `on` addrPriority) as
 
@@ -437,6 +452,8 @@ withRPC saddr cmd = withSimpleLogger do
 
                       RPCPing{} -> pause @'Seconds 0.1 >> liftIO exitSuccess
 
+                      RPCFetch{} -> pause @'Seconds 0.1 >> liftIO exitSuccess
+
                       _ -> pure ()
 
                     void $ liftIO $ waitAnyCatchCancel [proto]
@@ -445,15 +462,17 @@ withRPC saddr cmd = withSimpleLogger do
 
   where
     adapter = RpcAdapter dontHandle
-                         (const $ debug "alive-and-kicking" >> liftIO exitSuccess)
+                         (const $ notice "alive-and-kicking" >> liftIO exitSuccess)
                          (const $ liftIO exitSuccess)
                          (const $ debug "wat?")
+                         dontHandle
 
 runRpcCommand :: String -> RPCCommand -> IO ()
 runRpcCommand saddr = \case
   POKE -> withRPC saddr (RPCPoke @UDP)
   PING s -> withRPC saddr (RPCPing s)
   ANNOUNCE h -> withRPC saddr (RPCAnnounce @UDP h)
+  FETCH h  -> withRPC saddr (RPCFetch @UDP h)
 
   _ -> pure ()
 

hbs2-peer/app/RPC.hs

@@ -18,6 +18,7 @@ data RPC e =
   | RPCPing (PeerAddr e)
   | RPCPokeAnswer
   | RPCAnnounce (Hash HbSync)
+  | RPCFetch (Hash HbSync)
   deriving stock (Generic)
 
 
@@ -44,6 +45,7 @@ data RpcAdapter e m =
   , rpcOnPokeAnswer  :: RPC e -> m ()
   , rpcOnAnnounce    :: Hash HbSync -> m ()
   , rpcOnPing        :: PeerAddr e -> m ()
+  , rpcOnFetch       :: Hash HbSync -> m ()
   }
 
 newtype RpcM m a = RpcM { fromRpcM :: ReaderT RPCEnv m a }
@@ -85,4 +87,5 @@ rpcHandler adapter = \case
     p@RPCPokeAnswer{} -> rpcOnPokeAnswer adapter p
     (RPCAnnounce h)   -> rpcOnAnnounce adapter h
     (RPCPing pa)      -> rpcOnPing adapter pa
+    (RPCFetch h)      -> rpcOnFetch adapter h