Add customer management implementation for multithreading

customer-management/app/Main.hs

@@ -1,12 +1,12 @@
 module Main where
 
+import Control.Concurrent.Async (async, wait)
 import Control.Monad (forM_)
 import Customer (Customer (..))
 import CustomerLogger (CustomerLogger (..))
 import CustomerMasker (CustomerMasker (..))
 import CustomerVisualizer
   ( CustomerVisualizable (..),
-    CustomerVisualizer (..),
   )
 import InternalCustomer (InternalCustomer (..))
 import VipCustomer (VipCustomer (..))
@@ -39,10 +39,18 @@ main = do
                 department = "IT"
               }
         ]
-  forM_ customers doActions
+
+  let wrappedCustomers = fmap addWrappers customers
+  threads <- mapM (async . doActions wrappedCustomers) [1 .. 50]
+  forM_ threads wait
   where
-    doActions :: forall a. CustomerVisualizer a => a -> IO ()
-    doActions customer = do
-      let customerMasker = CustomerMasker customer
-      let customerLogger = CustomerLogger customerMasker
-      V.printInfo customerLogger
+    addWrappers :: CustomerVisualizable -> CustomerVisualizable
+    addWrappers customer =
+      CustomerVisualizable
+        ( CustomerLogger (CustomerMasker customer)
+        )
+
+    doActions :: [CustomerVisualizable] -> Int -> IO ()
+    doActions customers nth = do
+      forM_ customers V.printInfo
+      putStrLn ("#" <> show nth)

customer-management/customer-management.cabal

@@ -4,7 +4,7 @@ cabal-version: 1.12
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 025fdee50f6d19a67ef556e4e5e4dadfad44b41c7fa7114b6e1c8d33ec39880a
+-- hash: 889d9b59a608d5741991d10e9e45d31a8ffd40ef2c4032b77c7a8f4f781c8778
 
 name:           customer-management
 version:        0.1.0.0
@@ -40,7 +40,8 @@ library
       src
   default-extensions: DuplicateRecordFields ExistentialQuantification
   build-depends:
-      base >=4.7 && <5
+      async >=2.1 && <3
+    , base >=4.7 && <5
   default-language: Haskell2010
 
 executable customer-management-exe
@@ -52,7 +53,8 @@ executable customer-management-exe
   default-extensions: DuplicateRecordFields ExistentialQuantification
   ghc-options: -threaded -rtsopts -with-rtsopts=-N
   build-depends:
-      base >=4.7 && <5
+      async >=2.1 && <3
+    , base >=4.7 && <5
     , customer-management
   default-language: Haskell2010
 
@@ -66,6 +68,7 @@ test-suite customer-management-test
   default-extensions: DuplicateRecordFields ExistentialQuantification
   ghc-options: -threaded -rtsopts -with-rtsopts=-N
   build-depends:
-      base >=4.7 && <5
+      async >=2.1 && <3
+    , base >=4.7 && <5
     , customer-management
   default-language: Haskell2010

customer-management/package.yaml

@@ -25,6 +25,7 @@ default-extensions:
 
 dependencies:
   - base >= 4.7 && < 5
+  - async >= 2.1 && < 3
 
 library:
   source-dirs: src