instrumentation script executes the prepared schedule

- reads CSV schedule from file
- sends the given schedule of post events
- not thoroughly tested yet

implements #59

app/Experiment.hs

@@ -3,42 +3,49 @@
 module Main where
 
 import           Control.Concurrent
-import           Control.Monad              (forM_)
-import           Control.Monad.IO.Class
-import           Control.Monad.State.Class
-import           Control.Monad.State.Strict (evalStateT)
-import qualified Network.HTTP.Client        as HTTP
-import           System.Random
+import           Control.Monad        (forM_)
+import qualified Data.Text.Lazy       as Txt
+import qualified Data.Text.Lazy.IO    as TxtI
+import qualified Network.HTTP.Client  as HTTP
+import           System.Environment   (getArgs)
 
-import           Hash2Pub.PostService       (Hashtag, clientPublishPost)
+import           Hash2Pub.PostService (Hashtag, clientPublishPost)
 
--- placeholder post data definition
-
-tagsToPostTo = [ "JustSomeTag", "WantAnotherTag234", "HereWeGoAgain", "Oyä", "通信端末" ]
-
-knownRelays :: [(String, Int)]
-knownRelays =
-  [ ("animalliberation.social", 3342)
-  , ("hostux.social", 3343)
-  , ("social.diskseven.com", 3344)
-  , ("social.imirhil.fr", 3345)
-  ]
+-- configuration constants
+timelineFile = "../simulationData/inputs/generated/timeline_sample.csv"
 
 main :: IO ()
 main = do
+    -- read CLI parameters
+    speedupStr : _ <- getArgs
+    -- read and parse timeline schedule
+    -- relying on lazyness of HaskellIO, hoping it does not introduce too strong delays
+    postEvents <- parseSchedule <$> TxtI.readFile timelineFile
+    -- actually schedule and send the post events
+    executeSchedule (read speedupStr) postEvents
+    pure ()
+
+
+
+parseSchedule :: Txt.Text
+              -> [(Int, Hashtag, (String, Int))] -- ^ [(delay in microseconds, hashtag, (hostname, port))]
+parseSchedule = fmap (parseEntry . Txt.split (== ';')) . Txt.lines
+  where
+      parseEntry [delayT, contactT, tag] =
+          (read $ Txt.unpack delayT, tag, read $ Txt.unpack contactT)
+      parseEntry _ = error "invalid schedule input format"
+
+executeSchedule :: Int  -- ^ speedup factor
+                -> [(Int, Hashtag, (String, Int))] -- ^ [(delay in microseconds, hashtag, (hostname, port))]
+                -> IO ()
+executeSchedule speedup events = do
     -- initialise HTTP manager
     httpMan <- HTTP.newManager HTTP.defaultManagerSettings
-    -- initialise RNG
-    let initRGen = mkStdGen 12
-    -- cycle through tags and post to a random instance
-    evalStateT (forM_ (cycle tagsToPostTo) $ publishPostRandom httpMan) initRGen
-    -- wait for a specified time
-
-publishPostRandom :: (RandomGen g, MonadIO m, MonadState g m) => HTTP.Manager -> Hashtag -> m ()
-publishPostRandom httpman tag = do
-    index <- state $ randomR (0, length knownRelays - 1)
-    let (pubHost, pubPort) = knownRelays !! index
-    _ <- liftIO . forkIO $ do
-        postResult <- liftIO $ clientPublishPost httpman pubHost pubPort ("foobar #" <> tag)
-        either putStrLn (const $ pure ()) postResult
-    liftIO $ threadDelay 500
+    forM_ events $ \(delay, tag, (pubHost, pubPort)) -> do
+        _ <- forkIO $
+            clientPublishPost httpMan pubHost pubPort ("foobar #" <> tag)
+            >>= either putStrLn (const $ pure ())
+        -- while threadDelay gives only minimum delay guarantees, let's hope the
+        -- additional delays are negligible
+        -- otherwise: evaluate usage of https://hackage.haskell.org/package/schedule-0.3.0.0/docs/Data-Schedule.html
+        threadDelay $ delay `div` speedup