@@ -1,6 +1,9 @@
11{-# LANGUAGE FlexibleContexts #-}
22{-# LANGUAGE LambdaCase #-}
33{-# LANGUAGE OverloadedStrings #-}
4+{-# LANGUAGE ScopedTypeVariables #-}
5+{-# LANGUAGE TupleSections #-}
6+
47module Obelisk.Command.Project
58 ( InitSource (..)
69 , findProjectObeliskCommand
@@ -16,12 +19,18 @@ module Obelisk.Command.Project
1619 , toObeliskDir
1720 , withProjectRoot
1821 , bashEscape
22+ , getHaskellManifestProjectPath
23+ , AssetSource(..)
24+ , describeImpureAssetSource
25+ , watchStaticFilesDerivation
1926 ) where
2027
2128import Control.Concurrent.MVar (MVar, newMVar, withMVarMasked)
22−import Control.Lens ((.~), (?~), (<&>))
29+import Control.Lens ((.~), (?~), (<&>), (^.), _2, _3)
2330import Control.Monad
31+import Control.Monad.Except
2432import Control.Monad.IO.Class (liftIO)
33+import Control.Monad.Log
2534import Control.Monad.State
2635import qualified Data.Aeson as Json
2736import qualified Data.ByteString.UTF8 as BSU
@@ -30,24 +39,32 @@ import qualified Data.ByteString.Lazy as BSL
3039import Data.Default (def)
3140import Data.Function ((&), on)
3241import Data.Map (Map)
42+import Data.Maybe (isJust)
3343import Data.Text (Text)
3444import qualified Data.Text as T
3545import Data.Text.Encoding (decodeUtf8, encodeUtf8)
3646import Data.Traversable (for)
47+import Reflex
48+import Reflex.FSNotify
49+import Reflex.Host.Headless
3750import System.Directory
3851import System.Environment (lookupEnv)
52+import System.Exit (ExitCode(..))
3953import System.FilePath
54+import System.FSNotify (defaultConfig, eventPath, WatchConfig(..))
55+import qualified System.Info as SysInfo
4056import System.IO.Temp
4157import System.IO.Unsafe (unsafePerformIO)
4258import System.PosixCompat.Files
4359import System.PosixCompat.Types
4460import System.PosixCompat.User
61+import qualified System.Process as Proc
4562import Text.ShellEscape (bash, bytes)
4663
4764import GitHub.Data.GitData (Branch)
4865import GitHub.Data.Name (Name)
4966
50−import Obelisk.App (MonadObelisk)
67+import Obelisk.App (MonadObelisk, runObelisk, getObelisk)
5168import Obelisk.CliApp
5269import Obelisk.Command.Nix
5370import Obelisk.Command.Thunk
@@ -334,7 +351,21 @@ nixShellWithHoogle root isPure shell' command = do
334351 \})).project.shells.${shell}"
335352 & nixShellConfig_common . nixCmdConfig_args .~ [ strArg "shell" shell' ]
336353
337−findProjectAssets :: MonadObelisk m => FilePath -> m Text
354+-- | Describes the provenance of static assets (i.e., are they the result of a derivation
355+-- that was built, or just a folder full of files.
356+data AssetSource = AssetSource_Derivation
357+ | AssetSource_Files
358+ deriving (Eq)
359+
360+-- | Some log messages to make it easier to tell where static files are coming from
361+describeImpureAssetSource :: AssetSource -> Text -> Text
362+describeImpureAssetSource src path = case src of
363+ AssetSource_Files -> "Assets impurely loaded from: " <> path
364+ AssetSource_Derivation -> "Assets derivation built and impurely loaded from: " <> path
365+
366+-- | Determine where the static files of a project are and whether they're plain files or a derivation.
367+-- If they are a derivation, that derivation will be built.
368+findProjectAssets :: MonadObelisk m => FilePath -> m (AssetSource, Text)
338369findProjectAssets root = do
339370 isDerivation <- readProcessAndLogStderr Debug $ setCwd (Just root) $
340371 proc nixExePath
@@ -346,10 +377,91 @@ findProjectAssets root = do
346377 ]
347378 -- Check whether the impure static files are a derivation (and so must be built)
348379 if isDerivation == "1"
349− then fmap T.strip $ readProcessAndLogStderr Debug $ setCwd (Just root) $ -- Strip whitespace here because nix-build has no --raw option
350− proc nixBuildExePath
351− [ "--no-out-link"
380+ then do
381+ _ <- buildStaticFilesDerivationAndSymlink
382+ (readProcessAndLogStderr Debug)
383+ root
384+ pure (AssetSource_Derivation, T.pack $ root </> "static.out")
385+ else fmap (AssetSource_Files,) $ readProcessAndLogStderr Debug $ setCwd (Just root) $
386+ proc nixExePath ["eval", "-f", ".", "passthru.staticFilesImpure", "--raw"]
387+
388+-- | Get the nix store path to the generated static asset manifest module (e.g., "obelisk-generated-static")
389+getHaskellManifestProjectPath :: MonadObelisk m => FilePath -> m Text
390+getHaskellManifestProjectPath root = fmap T.strip $ readProcessAndLogStderr Debug $ setCwd (Just root) $
391+ proc nixBuildExePath
392+ [ "--no-out-link"
393+ , "-E"
394+ , "(let a = import ./. {}; in a.passthru.processedStatic.haskellManifest)"
395+ ]
396+
397+-- | Watch the project directory for file changes and check whether those file changes
398+-- cause changes in the static files nix derivation. If so, rebuild it.
399+watchStaticFilesDerivation
400+ :: (MonadIO m, MonadObelisk m)
401+ => FilePath
402+ -> m ()
403+watchStaticFilesDerivation root = do
404+ ob <- getObelisk
405+ drv0 <- showDerivation
406+ liftIO $ runHeadlessApp $ do
407+ pb <- getPostBuild
408+ checkForChanges <- batchOccurrences 0.25 =<< watchDirectoryTree
409+ -- On macOS, use the polling backend due to https://github.com/luite/hfsevents/issues/13
410+ (defaultConfig { confUsePolling = SysInfo.os == "darwin", confPollInterval = 250000 })
411+ (root <$ pb)
412+ ((/="static.out") . takeFileName . eventPath)
413+ drv <- performEvent $ ffor checkForChanges $ \_ ->
414+ liftIO $ runObelisk ob showDerivation
415+ drvs <- foldDyn (\new (_, old, _) -> (old, new, old /= new)) (drv0, drv0, False) drv
416+ void $ throttleBatchWithLag
417+ (\e -> performEvent $ ffor e $ \_ -> liftIO $ runObelisk ob $ do
418+ putLog Notice "Static assets being built..."
419+ buildStaticCatchErrors >>= \case
420+ Nothing -> pure ()
421+ Just _ -> putLog Notice "Static assets built and symlinked to static.out"
422+ )
423+ ((() <$) . ffilter (\x -> isJust (x ^._2) && x ^._3) $ updated drvs)
424+ pure never
425+ where
426+ handleBuildFailure
427+ :: MonadObelisk m
428+ => (ExitCode, String, String)
429+ -> m (Maybe Text)
430+ handleBuildFailure (ex, out, err) = case ex of
431+ ExitSuccess -> pure $ Just $ T.pack out
432+ _ -> do
433+ putLog Error $
434+ ("Static assets build failed: " <>) $
435+ T.unlines $ reverse $ take 10 $ reverse $ T.lines $ T.pack err
436+ pure Nothing
437+ showDerivation :: MonadObelisk m => m (Maybe Text)
438+ showDerivation =
439+ handleBuildFailure <=< readCreateProcessWithExitCode $
440+ setCwd (Just root) $ ProcessSpec
441+ { _processSpec_createProcess = Proc.proc nixExePath
442+ [ "show-derivation"
443+ , "-f", "."
444+ , "passthru.staticFilesImpure"
445+ ]
446+ , _processSpec_overrideEnv = Nothing
447+ }
448+ buildStaticCatchErrors :: MonadObelisk m => m (Maybe Text)
449+ buildStaticCatchErrors = handleBuildFailure =<<
450+ buildStaticFilesDerivationAndSymlink
451+ readCreateProcessWithExitCode
452+ root
453+
454+buildStaticFilesDerivationAndSymlink
455+ :: MonadObelisk m
456+ => (ProcessSpec -> m a)
457+ -> FilePath
458+ -> m a
459+buildStaticFilesDerivationAndSymlink f root = f $
460+ setCwd (Just root) $ ProcessSpec
461+ { _processSpec_createProcess = Proc.proc
462+ nixBuildExePath
463+ [ "-o", "static.out"
352464 , "-E", "(import ./. {}).passthru.staticFilesImpure"
353465 ]
354− else readProcessAndLogStderr Debug $ setCwd (Just root) $
355− proc nixExePath ["eval", "-f", ".", "passthru.staticFilesImpure", "--raw"]
466+ , _processSpec_overrideEnv = Nothing
467+ }