Hash2Pub/app/Main.hs

module Main where

import           Control.Concurrent
import           Control.Concurrent.Async
import           Control.Concurrent.STM
import           Control.Concurrent.STM.TVar
import           Control.Exception
import           Data.Either
import           Data.IP                     (IPv6, toHostAddress6)
import           System.Environment

import           Hash2Pub.FediChord

main :: IO ()
main = do
    -- ToDo: parse and pass config
    -- probably use `tomland` for that
    conf <- readConfig
    -- ToDo: load persisted caches, bootstrapping nodes …
    (serverSock, thisNode) <- fediChordInit conf
    print =<< readTVarIO thisNode
    print serverSock
    -- currently no masking is necessary, as there is nothing to clean up
    cacheWriterThread <- forkIO $ cacheWriter thisNode
    -- try joining the DHT using one of the provided bootstrapping nodes
    let
        tryJoining (bn:bns) = do
            j <- fediChordBootstrapJoin thisNode bn
            case j of
              Left err -> putStrLn ("join error: " <> err) >> tryJoining bns
              Right joined -> pure $ Right joined
        tryJoining [] = pure $ Left "Exhausted all bootstrap points for joining."
    joinedState <- tryJoining $ confBootstrapNodes conf
    either (\err -> do
        -- handle unsuccessful join

        putStrLn $ err <> " Error joining, start listening for incoming requests anyways"
        print =<< readTVarIO thisNode
        wait =<< async (fediMainThreads serverSock thisNode)
        -- TODO: periodic retry
           )
           (\joinedNS -> do
        -- launch main eventloop with successfully joined state
        putStrLn "successful join"
        wait =<< async (fediMainThreads serverSock thisNode)
           )
        joinedState
    pure ()


readConfig :: IO FediChordConf
readConfig = do
    confDomainString : ipString : portString : bootstrapHost : bootstrapPortString : _ <- getArgs
    pure $ FediChordConf {
        confDomain = confDomainString
      , confIP = toHostAddress6 . read $ ipString
      , confDhtPort = read portString
      , confBootstrapNodes = [(bootstrapHost, read bootstrapPortString)]
      --, confStabiliseInterval = 60
                           }