wasp start now does setup and start while forwarding output.

fix

waspc/.stylish-haskell.yaml

@@ -0,0 +1,230 @@
+# stylish-haskell configuration file
+# ==================================
+
+# The stylish-haskell tool is mainly configured by specifying steps. These steps
+# are a list, so they have an order, and one specific step may appear more than
+# once (if needed). Each file is processed by these steps in the given order.
+steps:
+  # Convert some ASCII sequences to their Unicode equivalents. This is disabled
+  # by default.
+  # - unicode_syntax:
+  #     # In order to make this work, we also need to insert the UnicodeSyntax
+  #     # language pragma. If this flag is set to true, we insert it when it's
+  #     # not already present. You may want to disable it if you configure
+  #     # language extensions using some other method than pragmas. Default:
+  #     # true.
+  #     add_language_pragma: true
+
+  # Align the right hand side of some elements.  This is quite conservative
+  # and only applies to statements where each element occupies a single
+  # line. All default to true.
+  - simple_align:
+      cases: true
+      top_level_patterns: true
+      records: true
+
+  # Import cleanup
+  - imports:
+      # There are different ways we can align names and lists.
+      #
+      # - global: Align the import names and import list throughout the entire
+      #   file.
+      #
+      # - file: Like global, but don't add padding when there are no qualified
+      #   imports in the file.
+      #
+      # - group: Only align the imports per group (a group is formed by adjacent
+      #   import lines).
+      #
+      # - none: Do not perform any alignment.
+      #
+      # Default: global.
+      align: global
+
+      # The following options affect only import list alignment.
+      #
+      # List align has following options:
+      #
+      # - after_alias: Import list is aligned with end of import including
+      #   'as' and 'hiding' keywords.
+      #
+      #   > import qualified Data.List      as List (concat, foldl, foldr, head,
+      #   >                                          init, last, length)
+      #
+      # - with_alias: Import list is aligned with start of alias or hiding.
+      #
+      #   > import qualified Data.List      as List (concat, foldl, foldr, head,
+      #   >                                 init, last, length)
+      #
+      # - new_line: Import list starts always on new line.
+      #
+      #   > import qualified Data.List      as List
+      #   >     (concat, foldl, foldr, head, init, last, length)
+      #
+      # Default: after_alias
+      list_align: after_alias
+
+      # Right-pad the module names to align imports in a group:
+      #
+      # - true: a little more readable
+      #
+      #   > import qualified Data.List       as List (concat, foldl, foldr,
+      #   >                                           init, last, length)
+      #   > import qualified Data.List.Extra as List (concat, foldl, foldr,
+      #   >                                           init, last, length)
+      #
+      # - false: diff-safe
+      #
+      #   > import qualified Data.List as List (concat, foldl, foldr, init,
+      #   >                                     last, length)
+      #   > import qualified Data.List.Extra as List (concat, foldl, foldr,
+      #   >                                           init, last, length)
+      #
+      # Default: true
+      pad_module_names: true
+
+      # Long list align style takes effect when import is too long. This is
+      # determined by 'columns' setting.
+      #
+      # - inline: This option will put as much specs on same line as possible.
+      #
+      # - new_line: Import list will start on new line.
+      #
+      # - new_line_multiline: Import list will start on new line when it's
+      #   short enough to fit to single line. Otherwise it'll be multiline.
+      #
+      # - multiline: One line per import list entry.
+      #   Type with constructor list acts like single import.
+      #
+      #   > import qualified Data.Map as M
+      #   >     ( empty
+      #   >     , singleton
+      #   >     , ...
+      #   >     , delete
+      #   >     )
+      #
+      # Default: inline
+      long_list_align: inline
+
+      # Align empty list (importing instances)
+      #
+      # Empty list align has following options
+      #
+      # - inherit: inherit list_align setting
+      #
+      # - right_after: () is right after the module name:
+      #
+      #   > import Vector.Instances ()
+      #
+      # Default: inherit
+      empty_list_align: inherit
+
+      # List padding determines indentation of import list on lines after import.
+      # This option affects 'long_list_align'.
+      #
+      # - <integer>: constant value
+      #
+      # - module_name: align under start of module name.
+      #   Useful for 'file' and 'group' align settings.
+      #
+      # Default: 4
+      list_padding: 4
+
+      # Separate lists option affects formatting of import list for type
+      # or class. The only difference is single space between type and list
+      # of constructors, selectors and class functions.
+      #
+      # - true: There is single space between Foldable type and list of it's
+      #   functions.
+      #
+      #   > import Data.Foldable (Foldable (fold, foldl, foldMap))
+      #
+      # - false: There is no space between Foldable type and list of it's
+      #   functions.
+      #
+      #   > import Data.Foldable (Foldable(fold, foldl, foldMap))
+      #
+      # Default: true
+      separate_lists: true
+
+      # Space surround option affects formatting of import lists on a single
+      # line. The only difference is single space after the initial
+      # parenthesis and a single space before the terminal parenthesis.
+      #
+      # - true: There is single space associated with the enclosing
+      #   parenthesis.
+      #
+      #   > import Data.Foo ( foo )
+      #
+      # - false: There is no space associated with the enclosing parenthesis
+      #
+      #   > import Data.Foo (foo)
+      #
+      # Default: false
+      space_surround: false
+
+  # Language pragmas
+  - language_pragmas:
+      # We can generate different styles of language pragma lists.
+      #
+      # - vertical: Vertical-spaced language pragmas, one per line.
+      #
+      # - compact: A more compact style.
+      #
+      # - compact_line: Similar to compact, but wrap each line with
+      #   `{-#LANGUAGE #-}'.
+      #
+      # Default: vertical.
+      style: vertical
+
+      # Align affects alignment of closing pragma brackets.
+      #
+      # - true: Brackets are aligned in same column.
+      #
+      # - false: Brackets are not aligned together. There is only one space
+      #   between actual import and closing bracket.
+      #
+      # Default: true
+      align: true
+
+      # stylish-haskell can detect redundancy of some language pragmas. If this
+      # is set to true, it will remove those redundant pragmas. Default: true.
+      remove_redundant: true
+
+  # Replace tabs by spaces. This is disabled by default.
+  # - tabs:
+  #     # Number of spaces to use for each tab. Default: 8, as specified by the
+  #     # Haskell report.
+  #     spaces: 8
+
+  # Remove trailing whitespace
+  - trailing_whitespace: {}
+
+  # Squash multiple spaces between the left and right hand sides of some
+  # elements into single spaces. Basically, this undoes the effect of
+  # simple_align but is a bit less conservative.
+  # - squash: {}
+
+# A common setting is the number of columns (parts of) code will be wrapped
+# to. Different steps take this into account. Default: 80.
+columns: 80
+
+# By default, line endings are converted according to the OS. You can override
+# preferred format here.
+#
+# - native: Native newline format. CRLF on Windows, LF on other OSes.
+#
+# - lf: Convert to LF ("\n").
+#
+# - crlf: Convert to CRLF ("\r\n").
+#
+# Default: native.
+newline: native
+
+# Sometimes, language extensions are specified in a cabal file or from the
+# command line instead of using language pragmas in the file. stylish-haskell
+# needs to be aware of these, so it can parse the file correctly.
+#
+# No language extensions are enabled by default.
+language_extensions:
+  - QuasiQuotes

waspc/cli/Command.hs

@@ -5,7 +5,7 @@ module Command
     , CommandError(..)
     ) where
 
-import Control.Monad.Except (MonadError, ExceptT, runExceptT)
+import Control.Monad.Except (ExceptT, MonadError, runExceptT)
 import Control.Monad.IO.Class (MonadIO)
 
 
@@ -17,9 +17,8 @@ runCommand cmd = do
     errorOrResult <- runExceptT $ _runCommand cmd
     case errorOrResult of
         Left cmdError -> putStrLn $ "Error: " ++ _errorMsg cmdError
-        Right _ -> return ()
+        Right _       -> return ()
 
 -- TODO: What if we want to recognize errors in order to handle them?
 --   Should we add _commandErrorType? Should CommandError be parametrized by it, is that even possible?
 data CommandError = CommandError { _errorMsg :: !String }
-

waspc/cli/Command/Common.hs

@@ -1,6 +1,7 @@
 module Command.Common
     ( findWaspProjectRootFromCwd
     , findWaspProjectRoot
+    , waspSays
     ) where
 
 import System.Directory (getCurrentDirectory, doesPathExist, doesFileExist)
@@ -36,3 +37,6 @@ findWaspProjectRootFromCwd :: Command (Path Abs (Dir WaspProjectDir))
 findWaspProjectRootFromCwd = do
     absCurrentDir <- liftIO getCurrentDirectory
     findWaspProjectRoot (fromJust $ SP.parseAbsDir absCurrentDir)
+
+waspSays :: String -> Command ()
+waspSays what = liftIO $ putStrLn $ "\ESC[33m{= Wasp =}\ESC[0m " ++ what -- Yellow

waspc/cli/Command/Start.hs

@@ -13,7 +13,7 @@ import qualified StrongPath as SP
 import qualified Lib
 import qualified Util.IO
 import Command (Command, CommandError(..))
-import Command.Common (findWaspProjectRootFromCwd)
+import Command.Common (findWaspProjectRootFromCwd, waspSays)
 import qualified Common
 
 
@@ -26,8 +26,11 @@ start = do
             { externalCodeDirPath = waspRoot </> Common.extCodeDirInWaspProjectDir }
 
     -- TODO: This just compiles once. We need `wasp start` to do much more.
-    maybeError <- liftIO $ Lib.compile waspFile outDir options
-    liftIO $ either putStrLn (\_ -> print ("Code has been successfully (re)generated." :: String)) maybeError
+    waspSays "Compiling wasp code..."
+    errorOrResult <- liftIO $ Lib.compile waspFile outDir options
+    case errorOrResult of
+        Left compileError -> throwError $ CommandError $ "Compilation failed: " ++ compileError
+        Right () -> waspSays "Code has been successfully compiled.\n"
 
     -- TODO: Do smart install -> if we need to install stuff, install it.
     --   This should be responsibility of Generator, it should tell us how to install stuff.
@@ -36,16 +39,21 @@ start = do
     --   Then, next time, we give it data we have about last installation, and it uses that
     --   to decide if installation needs to happen or not. If it happens, it returnes new data again.
     --   Right now we have setup/installation being called, but it has not support for being "smart" yet.
-    liftIO $ putStrLn "Setting up generated project..."
-    setupResult <- liftIO $ Lib.setup outDir options
+    waspSays "Setting up generated project..."
+    setupResult <- liftIO $ Lib.setup outDir
     case setupResult of
         Left setupError -> throwError $ CommandError $ "Setup failed: " ++ setupError
-        Right () -> liftIO $ putStrLn "Setup successful."
+        Right () -> waspSays "Setup successful.\n"
 
     -- TODO: Check node version and then run `npm start` on both web and server.
     --   Again, this is something that Generator should be responsible for, since it knows how the code is generated.
     --   It should tell us how to start stuff and we just start it. It should even do composing of the outputs,
     --   since it knows more than us about that.
+    waspSays "Starting up generated project..."
+    startResult <- liftIO $ Lib.start outDir
+    case startResult of
+        Left startError -> throwError $ CommandError $ "Start failed: " ++ startError
+        Right () -> error "This should never happen, start should never end."
 
     -- TODO: Listen for changes, if they happen, re-generate the code.
   where

waspc/package.yaml

@@ -54,6 +54,10 @@ library:
     - time
     - exceptions
     - process
+    - conduit
+    - conduit-extra
+    - async
+    - bytestring
 
 executables:
   wasp:

waspc/src/Generator.hs

@@ -1,27 +1,27 @@
 module Generator
        ( writeWebAppCode
-       , setup
+       , Generator.Setup.setup
+       , Generator.Start.start
        ) where
 
 import qualified Data.Text
 import qualified Data.Text.IO
-import Data.Time.Clock
-import qualified Paths_waspc
+import           Data.Time.Clock
 import qualified Data.Version
-import Control.Monad (mapM_)
-import qualified Path as P
-import System.Exit (ExitCode(..))
+import qualified Path                      as P
+import qualified Paths_waspc
 
-import StrongPath (Path, Abs, Dir, (</>))
-import qualified StrongPath as SP
-import CompileOptions (CompileOptions)
-import Wasp (Wasp)
-import Generator.WebAppGenerator (generateWebApp)
-import Generator.ServerGenerator (genServer)
-import Generator.DbGenerator (genDb)
-import qualified Generator.ServerGenerator.Setup
-import Generator.FileDraft (FileDraft, write)
-import Generator.Common (ProjectRootDir)
+import           CompileOptions            (CompileOptions)
+import           Generator.Common          (ProjectRootDir)
+import           Generator.DbGenerator     (genDb)
+import           Generator.FileDraft       (FileDraft, write)
+import           Generator.ServerGenerator (genServer)
+import qualified Generator.Setup
+import qualified Generator.Start
+import           Generator.WebAppGenerator (generateWebApp)
+import           StrongPath                (Abs, Dir, Path, (</>))
+import qualified StrongPath                as SP
+import           Wasp                      (Wasp)
 
 
 -- | Generates web app code from given Wasp and writes it to given destination directory.
@@ -50,21 +50,3 @@ writeDotWaspInfo dstDir = do
     let content = "Generated on " ++ (show currentTime) ++ " by waspc version " ++ (show version) ++ " ."
     let dstPath = dstDir </> SP.fromPathRelFile [P.relfile|.waspinfo|]
     Data.Text.IO.writeFile (SP.toFilePath dstPath) (Data.Text.pack content)
-
-setup :: Path Abs (Dir ProjectRootDir) -> CompileOptions -> IO (Either String ())
-setup outDir _ = do
-   serverResult <- setupServer
-   webAppResult <- setupWebApp
-   return serverResult -- TODO: Should merge server results with web app results.
-  where
-      setupServer = do
-          (exitCode, stdout, stderr) <- Generator.ServerGenerator.Setup.setupServer outDir
-          print stdout
-          print stderr
-          case exitCode of
-              ExitSuccess -> return $ Right ()
-              ExitFailure failureCode -> return $ Left $ "Server installation failed with exit code " ++ (show failureCode)
-
-      setupWebApp = do -- TODO: Implement.
-          putStrLn "Pretending to be setting up web app."
-          return $ Right ()

waspc/src/Generator/Job.hs

@@ -0,0 +1,29 @@
+module Generator.Job
+    ( Job
+    , JobMessage (..)
+    , JobMessageData (..)
+    , JobOutputType (..)
+    , JobType (..)
+    ) where
+
+import           Control.Concurrent (Chan)
+import           System.Exit        (ExitCode)
+
+
+-- | Job is an IO action that communicates progress by writing messages to given channel
+--   until it is done, when it returns exit code.
+type Job = Chan JobMessage -> IO ExitCode
+
+data JobMessage = JobMessage
+    { _data    :: JobMessageData
+    , _jobType :: JobType
+    }
+    deriving (Show)
+
+data JobMessageData = JobOutput String JobOutputType
+                    | JobExit ExitCode
+    deriving (Show)
+
+data JobOutputType = Stdout | Stderr deriving (Show)
+
+data JobType = WebApp | Server deriving (Show)

waspc/src/Generator/Job/IO.hs

@@ -0,0 +1,27 @@
+module Generator.Job.IO
+    ( printJobMessage
+    ) where
+
+import           System.Exit   (ExitCode (..))
+import           System.IO     (hPutStrLn, stderr, stdout)
+
+import qualified Generator.Job as J
+
+
+printJobMessage :: J.JobMessage -> IO ()
+printJobMessage jobMsg = do
+    let outHandle = case J._data jobMsg of
+            J.JobOutput _ outputType ->
+                case outputType of
+                    J.Stdout -> stdout
+                    J.Stderr -> stderr
+            J.JobExit _ -> stderr
+    let prefix = case J._jobType jobMsg of
+            J.Server -> "\ESC[35mServer:\ESC[0m " -- Magenta
+            J.WebApp -> "\ESC[36mWeb app:\ESC[0m " -- Cyan
+    let message = case J._data jobMsg of
+            J.JobOutput output _ -> output
+            J.JobExit ExitSuccess -> "Job exited successfully."
+            J.JobExit (ExitFailure exitCode) -> "Job failed with exit code " ++ show exitCode
+    let outputLines = map (\l -> prefix ++ l) (lines message)
+    mapM_ (hPutStrLn outHandle) outputLines

waspc/src/Generator/Job/Process.hs

@@ -0,0 +1,49 @@
+module Generator.Job.Process
+    ( runProcessAsJob
+    , runNodeCommandAsJob
+    ) where
+
+import           Control.Concurrent    (writeChan)
+import qualified Data.ByteString.Char8 as BS
+import           Data.Conduit          (runConduit, (.|))
+import qualified Data.Conduit.List     as CL
+import qualified Data.Conduit.Process  as CP
+import qualified System.Process        as P
+
+import qualified Generator.Job         as J
+import           StrongPath            (Abs, Dir, Path)
+import qualified StrongPath            as SP
+
+
+-- | Runs a given process while streaming its stderr and stdout to provided channel.
+--   Returns exit code of the process once it finishes, and also sends it to he channel.
+runProcessAsJob :: P.CreateProcess -> J.JobType -> J.Job
+runProcessAsJob process jobType = \chan -> do
+    (CP.ClosedStream, stdoutStream, stderrStream, processHandle) <- CP.streamingProcess process
+
+    -- TODO: Do I need to use Concurrently to run concurrently these three below:
+    --   stdout, sdterr, and waiting for process? They do it in documentation/tutorial:
+    --   https://github.com/snoyberg/conduit/blob/master/PROCESS.md .
+    --   But for me it works fine without it, for now.
+
+    runConduit $ stdoutStream .| CL.mapM_
+        (\bs -> writeChan chan $ J.JobMessage { J._data = J.JobOutput (BS.unpack bs) J.Stdout
+                                              , J._jobType = jobType })
+
+    runConduit $ stderrStream .| CL.mapM_
+        (\bs -> writeChan chan $ J.JobMessage { J._data = J.JobOutput (BS.unpack bs) J.Stderr
+                                              , J._jobType = jobType })
+
+    exitCode <- CP.waitForStreamingProcess processHandle
+
+    writeChan chan $ J.JobMessage { J._data = J.JobExit exitCode
+                                  , J._jobType = jobType }
+
+    return exitCode
+
+runNodeCommandAsJob :: Path Abs (Dir a) -> String -> [String] -> J.JobType -> J.Job
+runNodeCommandAsJob fromDir command args jobType = do
+    -- TODO: Check npm/node version.
+    let process = (P.proc command args) { P.cwd = Just $ SP.toFilePath fromDir }
+    runProcessAsJob process jobType
+

waspc/src/Generator/ServerGenerator/Setup.hs

@@ -2,24 +2,14 @@ module Generator.ServerGenerator.Setup
     ( setupServer
     ) where
 
-import qualified System.Process as P
-import System.Exit (ExitCode(..))
+import           Generator.Common                 (ProjectRootDir)
+import qualified Generator.Job                    as J
+import           Generator.Job.Process            (runNodeCommandAsJob)
+import qualified Generator.ServerGenerator.Common as Common
+import           StrongPath                       (Abs, Dir, Path, (</>))
 
-import qualified StrongPath as SP
-import StrongPath (Path, Abs, Dir)
-import qualified Generator.ServerGenerator.Common as C
-import Generator.Common (ProjectRootDir)
 
-type Stdout = String
-type Stderr = String
-
-setupServer :: Path Abs (Dir ProjectRootDir) -> IO (ExitCode, Stdout, Stderr)
+setupServer :: Path Abs (Dir ProjectRootDir) -> J.Job
 setupServer projectDir = do
-    let serverDir = projectDir SP.</> C.serverRootDirInProjectRootDir
-
-    -- TODO: Check npm/node version.
-
-    let process = (P.proc "npm" ["install"]){ P.cwd = Just (SP.toFilePath serverDir) } -- TODO: Do I need to set more stuff here?
-    P.readCreateProcessWithExitCode process ""
-    -- TODO: What about exceptions that command above could throw, how do we handle those?
-
+    let serverDir = projectDir </> Common.serverRootDirInProjectRootDir
+    runNodeCommandAsJob serverDir "npm" ["install"] J.Server

waspc/src/Generator/ServerGenerator/Start.hs

@@ -2,22 +2,14 @@ module Generator.ServerGenerator.Start
     ( startServer
     ) where
 
-import qualified System.Process as P
-import System.Exit (ExitCode(..))
-
-import qualified StrongPath as SP
-import StrongPath (Path, Abs, Dir)
-import qualified Generator.ServerGenerator.Common as C
-import Generator.Common (ProjectRootDir)
+import           Generator.Common                 (ProjectRootDir)
+import qualified Generator.Job                    as J
+import           Generator.Job.Process            (runNodeCommandAsJob)
+import qualified Generator.ServerGenerator.Common as Common
+import           StrongPath                       (Abs, Dir, Path, (</>))
 
 
-startServer :: Path Abs (Dir ProjectRootDir) -> IO (ExitCode, String, String) -- ^ (exit code, stdout, stderr)
+startServer :: Path Abs (Dir ProjectRootDir) -> J.Job
 startServer projectDir = do
-    let serverDir = projectDir SP.</> C.serverRootDirInProjectRootDir
-
-    -- TODO: Check npm/node version.
-
-    -- TODO: npm start. I need to run process this in async manner!
-    --  Check out https://stackoverflow.com/a/47788165/1509394 .
-    error "To be implemented"
-
+    let serverDir = projectDir </> Common.serverRootDirInProjectRootDir
+    runNodeCommandAsJob serverDir "npm" ["start"] J.Server

waspc/src/Generator/Setup.hs

@@ -0,0 +1,43 @@
+module Generator.Setup
+       ( setup
+       ) where
+
+import           Control.Concurrent              (Chan, newChan, readChan)
+import           Control.Concurrent.Async        (concurrently)
+import           System.Exit                     (ExitCode (..))
+
+import           Generator.Common                (ProjectRootDir)
+import qualified Generator.Job                   as J
+import           Generator.Job.IO                (printJobMessage)
+import           Generator.ServerGenerator.Setup (setupServer)
+import           Generator.WebAppGenerator.Setup (setupWebApp)
+import           StrongPath                      (Abs, Dir, Path)
+
+
+setup :: Path Abs (Dir ProjectRootDir) -> IO (Either String ())
+setup projectDir = do
+    chan <- newChan
+    let runSetupJobs = concurrently (setupServer projectDir chan) (setupWebApp projectDir chan)
+    (_, result) <- concurrently (handleJobMessages chan (False, False)) runSetupJobs
+    case result of
+        (ExitSuccess, ExitSuccess) -> return $ Right ()
+        exitCodes -> return $ Left $ setupFailedMessage exitCodes
+  where
+      handleJobMessages :: Chan J.JobMessage -> (Bool, Bool) -> IO ()
+      handleJobMessages _ (True, True) = return ()
+      handleJobMessages chan (isWebAppDone, isServerDone) = do
+          jobMsg <- readChan chan
+          case J._data jobMsg of
+              J.JobOutput {} -> printJobMessage jobMsg >> handleJobMessages chan (isWebAppDone, isServerDone)
+              J.JobExit {} -> case J._jobType jobMsg of
+                  J.WebApp -> handleJobMessages chan (True, isServerDone)
+                  J.Server -> handleJobMessages chan (isWebAppDone, True)
+
+      setupFailedMessage (serverExitCode, webAppExitCode) =
+          let serverErrorMessage = case serverExitCode of
+                  ExitFailure code -> " Server setup failed with exit code " ++ show code ++ "."
+                  _ -> ""
+              webAppErrorMessage = case webAppExitCode of
+                  ExitFailure code -> " Web app setup failed with exit code " ++ show code ++ "."
+                  _ -> ""
+          in "Setup failed!" ++ serverErrorMessage ++ webAppErrorMessage

waspc/src/Generator/Start.hs

@@ -0,0 +1,31 @@
+module Generator.Start
+       ( start
+       ) where
+
+import           Control.Concurrent              (Chan, newChan, readChan)
+import           Control.Concurrent.Async        (race)
+
+import           Generator.Common                (ProjectRootDir)
+import           Generator.Job                   (JobMessage)
+import           Generator.Job.IO                (printJobMessage)
+import           Generator.ServerGenerator.Start (startServer)
+import           Generator.WebAppGenerator.Start (startWebApp)
+import           StrongPath                      (Abs, Dir, Path)
+
+
+-- | This is a blocking action, that will start the processes that run web app and server.
+--   It will wait for those processes to end, but since they are made to keep running until error
+--   occurs, so will this action, run until one of them fails or it fails itself.
+start :: Path Abs (Dir ProjectRootDir) -> IO (Either String ())
+start projectDir = do
+    chan <- newChan
+    let runStartJobs = race (startServer projectDir chan) (startWebApp projectDir chan)
+    result <- race (handleJobMessages chan) runStartJobs
+    case result of
+        Left () -> error "App start: Reading job messages stopped too early, this should never happen."
+        Right serverOrWebExitCode -> case serverOrWebExitCode of
+            Left serverExitCode -> return $ Left $ "Server failed with exit code " ++ show serverExitCode ++ "."
+            Right webAppExitCode -> return $ Left $ "Web app failed with exit code " ++ show webAppExitCode ++ "."
+  where
+      handleJobMessages :: Chan JobMessage -> IO ()
+      handleJobMessages chan = readChan chan >>= printJobMessage >> handleJobMessages chan

waspc/src/Generator/WebAppGenerator/Setup.hs

@@ -0,0 +1,15 @@
+module Generator.WebAppGenerator.Setup
+    ( setupWebApp
+    ) where
+
+import           Generator.Common                 (ProjectRootDir)
+import qualified Generator.Job                    as J
+import           Generator.Job.Process            (runNodeCommandAsJob)
+import qualified Generator.WebAppGenerator.Common as Common
+import           StrongPath                       (Abs, Dir, Path, (</>))
+
+
+setupWebApp :: Path Abs (Dir ProjectRootDir) -> J.Job
+setupWebApp projectDir = do
+    let webAppDir = projectDir </> Common.webAppRootDirInProjectRootDir
+    runNodeCommandAsJob webAppDir "npm" ["install"] J.WebApp

waspc/src/Generator/WebAppGenerator/Start.hs

@@ -0,0 +1,15 @@
+module Generator.WebAppGenerator.Start
+    ( startWebApp
+    ) where
+
+import           Generator.Common                 (ProjectRootDir)
+import qualified Generator.Job                    as J
+import           Generator.Job.Process            (runNodeCommandAsJob)
+import qualified Generator.WebAppGenerator.Common as Common
+import           StrongPath                       (Abs, Dir, Path, (</>))
+
+
+startWebApp :: Path Abs (Dir ProjectRootDir) -> J.Job
+startWebApp projectDir = do
+    let webAppDir = projectDir </> Common.webAppRootDirInProjectRootDir
+    runNodeCommandAsJob webAppDir "npm" ["start"] J.WebApp

waspc/src/Lib.hs

@@ -1,6 +1,7 @@
 module Lib
     ( compile
-    , setup
+    , Generator.setup
+    , Generator.start
     , ProjectRootDir
     ) where
 
@@ -28,8 +29,3 @@ compile waspFile outDir options = do
             generateCode $ wasp `setExternalCodeFiles` externalCodeFiles
   where
     generateCode wasp = Generator.writeWebAppCode wasp outDir options >> return (Right ())
-
-type SetupError = String
-
-setup :: Path Abs (Dir ProjectRootDir) -> CompileOptions -> IO (Either SetupError ())
-setup = Generator.setup