Move all the code into the library (src/) for maximum ergonomics

app/Main.hs

@@ -1,31 +1,6 @@
-{-# LANGUAGE NamedFieldPuns #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-
 module Main where
 
-import API.AppServices as AppServices
-import API.Application (app)
-import API.Config (Port (..), apiPort)
-import qualified API.Config as Config
-import CLIOptions (CLIOptions (configPath))
-import qualified CLIOptions
-import Dependencies (Deps (..))
-import qualified Dependencies as Deps
-import qualified Infrastructure.Logging.Logger as Logger
-import qualified Middleware
-import qualified Network.Wai.Handler.Warp as Warp
-import qualified Tagger.JSONWebKey as JWK
+import App
 
 main :: IO ()
-main = do
-  options <- CLIOptions.parse
-  appConfig <- Config.load $ configPath options
-  key <- JWK.setup options
-
-  Deps.withDeps appConfig $ \Deps {dbHandle, loggerHandle} -> do
-    let (Port port) = apiPort . Config.api $ appConfig
-        services = AppServices.start dbHandle loggerHandle key
-        application = Middleware.apply (app services)
-
-    Logger.logInfo loggerHandle $ "Starting app on port " <> show port <> "."
-    Warp.run port application
+main = run

package.yaml

@@ -46,20 +46,16 @@ dependencies:
   - transformers
   - uuid
   - wai
+  - wai-cors
+  - wai-extra
+  - warp
 
 executables:
   servant-template-exe:
     source-dirs:    app
     main:           Main.hs
     dependencies:
       - servant-template
-      - bytestring
-      - hasql
-      - jose
-      - transformers
-      - wai-cors
-      - wai-extra
-      - warp
 
 tests:
   servant-template-spec:

servant-template.cabal

@@ -23,7 +23,9 @@ library
       API.Docs
       API.Healthcheck
       API.Tagger
+      App
       CLIOptions
+      Dependencies
       Impl.Authentication.Authenticator
       Impl.Repository.Content
       Impl.Repository.Content.InMemory
@@ -40,6 +42,7 @@ library
       Infrastructure.Persistence.Schema
       Infrastructure.Persistence.Serializer
       Infrastructure.SystemTime
+      Middleware
       Tagger.Authentication.Authenticator
       Tagger.Authentication.Credentials
       Tagger.Content
@@ -86,13 +89,14 @@ library
     , transformers
     , uuid
     , wai
+    , wai-cors
+    , wai-extra
+    , warp
   default-language: Haskell2010
 
 executable servant-template-exe
   main-is: Main.hs
   other-modules:
-      Dependencies
-      Middleware
       Paths_servant_template
   hs-source-dirs:
       app
@@ -180,5 +184,7 @@ test-suite servant-template-spec
     , transformers
     , uuid
     , wai
+    , wai-cors
+    , wai-extra
     , warp
   default-language: Haskell2010

src/App.hs

@@ -0,0 +1,31 @@
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+
+module App where
+
+import API.AppServices as AppServices
+import API.Application (app)
+import API.Config (Port (..), apiPort)
+import qualified API.Config as Config
+import CLIOptions (CLIOptions (configPath))
+import qualified CLIOptions
+import Dependencies (Deps (..))
+import qualified Dependencies as Deps
+import qualified Infrastructure.Logging.Logger as Logger
+import qualified Middleware
+import qualified Network.Wai.Handler.Warp as Warp
+import qualified Tagger.JSONWebKey as JWK
+
+run :: IO ()
+run = do
+  options <- CLIOptions.parse
+  appConfig <- Config.load $ configPath options
+  key <- JWK.setup options
+
+  Deps.withDeps appConfig $ \Deps {dbHandle, loggerHandle} -> do
+    let (Port port) = apiPort . Config.api $ appConfig
+        services = AppServices.start dbHandle loggerHandle key
+        application = Middleware.apply (app services)
+
+    Logger.logInfo loggerHandle $ "Starting app on port " <> show port <> "."
+    Warp.run port application

app/Dependencies.hs → src/Dependencies.hs

@@ -1,4 +1,5 @@
 {-# LANGUAGE RecordWildCards #-}
+
 module Dependencies (withDeps, Deps (..)) where
 
 import qualified API.Config as Config