initialise own node state, preliminary config passing

Hash2Pub/Hash2Pub.cabal

@@ -74,7 +74,7 @@ executable Hash2Pub
   import: deps
 
   -- adding the library as a dependency
-  build-depends:       Hash2Pub
+  build-depends:       Hash2Pub, iproute
 
   -- .hs or .lhs file containing the Main module.
   main-is:             Main.hs

Hash2Pub/src/Hash2Pub/FediChord.hs

@@ -2,7 +2,7 @@
 {- |
 Module      : FediChord
 Description : An opinionated implementation of the EpiChord DHT by Leong et al.
-Copyright   : (c) schmittlauch, 2019
+Copyright   : (c) schmittlauch, 2019-2020
 License     : AGPL-3
 Stability   : experimental
 
@@ -36,6 +36,8 @@ module Hash2Pub.FediChord (
   , byteStringToUInteger
   , ipAddrAsBS
   , bsAsIpAddr
+  , FediChordConf(..)
+  , fediChordInit
                            ) where
 
 import qualified Data.Map.Strict as Map
@@ -392,3 +394,35 @@ checkCacheSlices state = case getNodeCache state of
 -- Todo: DHT backend can learn potential initial bootstrapping points through the instances mentioned in the received AP-relay messages
 -- needs to know its own domain anyways for ID generation
 -- persist them on disk so they can be used for all following bootstraps
+
+-- | configuration values used for initialising the FediChord DHT
+data FediChordConf = FediChordConf {
+    confDomain :: String
+  , confIP :: HostAddress6
+  , confDhtPort :: Int
+                                   } deriving (Show, Eq)
+
+-- | initialise data structures, compute own IDs.
+-- ToDo: load persisted state, thus this function already operates in IO
+fediChordInit :: FediChordConf -> IO NodeState
+fediChordInit conf = return $ NodeState {
+    domain = confDomain conf
+  , ipAddr = confIP conf
+  , nid = genNodeID (confIP conf) (confDomain conf) 0
+  , dhtPort = toEnum $ confDhtPort conf
+  , apPort = Nothing
+  , vServerID = 0
+  , internals = Just internalsInit
+                                        }
+      where
+          internalsInit = InternalNodeState {
+       nodeCache = initCache
+      , successors = []
+      , predecessors = []
+      , kNeighbours = 3
+      , lNumBestNodes = 3
+      , pNumParallelQueries = 2
+      , jEntriesPerSlice = 2
+                                       }
+
+

Hash2Pub/src/Hash2Pub/Main.hs

@@ -1,6 +1,25 @@
 module Main where
 
+import System.Environment
+import Data.IP (IPv6, toHostAddress6) -- iproute, just for IPv6 string parsing
+
 import Hash2Pub.FediChord
 
 main :: IO ()
-main = putStrLn "placeholder until later"
+main = do
+    -- ToDo: parse and pass config
+    -- probably use `tomland` for that
+    conf <- readConfig
+    -- ToDo: load persisted caches, bootstrapping nodes …
+    thisNode <- fediChordInit conf
+    print thisNode
+    return ()
+
+readConfig :: IO FediChordConf
+readConfig = do
+    confDomainString : ipString : portString : _ <- getArgs
+    return $ FediChordConf {
+        confDomain = confDomainString
+      , confIP = toHostAddress6 . read $ ipString
+      , confDhtPort = read portString
+                           }