Fix issues with servant. (#2240)

DB host was not being used. Max threads were being ignored.

frameworks/Haskell/servant/driver/Main.hs

@@ -1,13 +1,16 @@
 {-# LANGUAGE OverloadedStrings #-}
 module Main (main) where
 
-import Data.ByteString
+import Data.ByteString.Char8
 import ServantBench
 import Hasql.Connection (settings)
+import System.Environment (getArgs)
 
 main :: IO ()
-main = run 7041 dbSettings
+main = do
+  [host] <- getArgs
+  run 7041 $ dbSettings (pack host)
 
-dbSettings :: ByteString
-dbSettings
-  = settings "localhost" 5432 "benchmarkdbuser" "benchmarkdbpass" "hello_world"
+dbSettings :: ByteString -> ByteString
+dbSettings host
+  = settings host 5432 "benchmarkdbuser" "benchmarkdbpass" "hello_world"

frameworks/Haskell/servant/servant-bench.cabal

@@ -39,7 +39,7 @@ library
 
 executable servant-exe
   main-is:             Main.hs
-  ghc-options:         -Wall -threaded -rtsopts -with-rtsopts=-N -O2
+  ghc-options:         -Wall -threaded -rtsopts -O2
   build-depends:       base
                      , servant-bench
                      , bytestring

frameworks/Haskell/servant/setup.sh

@@ -5,4 +5,4 @@ fw_depends stack
 ${IROOT}/stack --allow-different-user setup
 ${IROOT}/stack --allow-different-user build
 
-${IROOT}/stack --allow-different-user exec servant-exe -- +RTS -A32m -N${MAX_THREADS} &
+${IROOT}/stack --allow-different-user exec servant-exe -- ${DBHOST} +RTS -A32m -N${MAX_THREADS} &