init

10 files changed, 539 insertions, 0 deletions

diff --git a/.envrc b/.envrc
new file mode 100644
index 0000000..1d953f4
--- /dev/null
+++ b/.envrc
@@ -0,0 +1 @@
+use nix
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..6a91ac4
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+/dist-newstyle
+/state
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..5566227
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,5 @@
+# Revision history for abuilder
+
+## 0.1.0.0 -- YYYY-mm-dd
+
+* First version. Released on an unsuspecting world.
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..d645695
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,202 @@
+
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+
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diff --git a/README.md b/README.md
new file mode 100644
index 0000000..bc997fc
--- /dev/null
+++ b/README.md
@@ -0,0 +1,11 @@
+# abuilder
+
+simple build daemon
+
+## usage
+
+```console
+export ABUILDER_STATE=./state
+export ABUILDER_URLS=$HOME/src/foo:$HOME/src/bar
+cabal run abuilder
+```
diff --git a/abuilder.cabal b/abuilder.cabal
new file mode 100644
index 0000000..fae0635
--- /dev/null
+++ b/abuilder.cabal
@@ -0,0 +1,33 @@
+cabal-version:   3.4
+name:            abuilder
+version:         0.1.0.0
+license:         Apache-2.0
+license-file:    LICENSE
+maintainer:      aforemny@posteo.de
+author:          Alexander Foremny
+build-type:      Simple
+extra-doc-files: CHANGELOG.md
+
+executable abuilder
+    main-is:          Main.hs
+    hs-source-dirs:   app
+    default-language: GHC2021
+    ghc-options:      -Wall -threaded
+    build-depends:
+        base,
+        bytestring,
+        containers,
+        directory,
+        filepath,
+        gitlib,
+        gitlib-libgit2,
+        hinotify,
+        mtl,
+        split,
+        stm,
+        string-interpolate,
+        tagged,
+        temporary,
+        text,
+        typed-process,
+        utf8-string
diff --git a/abuilder.nix b/abuilder.nix
new file mode 100644
index 0000000..7942680
--- /dev/null
+++ b/abuilder.nix
@@ -0,0 +1,2 @@
+{ haskellPackages }:
+haskellPackages.callCabal2nix "abuilder" ./. { }
diff --git a/app/Main.hs b/app/Main.hs
new file mode 100644
index 0000000..4765405
--- /dev/null
+++ b/app/Main.hs
@@ -0,0 +1,261 @@
+{-# LANGUAGE BlockArguments #-}
+{-# LANGUAGE OverloadedRecordDot #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE QuasiQuotes #-}
+{-# LANGUAGE ViewPatterns #-}
+{-# LANGUAGE NoFieldSelectors #-}
+{-# OPTIONS_GHC -fno-warn-name-shadowing #-}
+
+module Main where
+
+import Control.Concurrent
+import Control.Concurrent.STM
+import Control.Exception
+import Control.Monad
+import Data.ByteString.Lazy qualified as LB
+import Data.ByteString.Lazy.UTF8 qualified as LB
+import Data.ByteString.UTF8 qualified as B
+import Data.List.Split
+import Data.Map.Merge.Strict qualified as M
+import Data.Map.Strict qualified as M
+import Data.Maybe
+import Data.String.Interpolate (i)
+import Data.Tagged
+import Data.Text qualified as T
+import Git
+import Git.Libgit2
+import System.Directory
+import System.Environment
+import System.FilePath
+import System.INotify
+import System.IO
+import System.IO.Temp
+import System.IO.Unsafe
+import System.Process.Typed
+import Text.Printf
+
+stateDirectory :: FilePath
+stateDirectory = unsafePerformIO (getEnv "ABUILDER_STATE")
+
+ref :: String
+ref = fromMaybe "main" (unsafePerformIO (lookupEnv "ABUILDER_BRANCH"))
+
+type JobName = String
+
+type Url = FilePath
+
+urls :: M.Map JobName Url
+urls =
+  M.fromList . map ((,) <$> takeBaseName <*> id) $
+    splitOn ":" (unsafePerformIO (getEnv "ABUILDER_URLS"))
+
+concurrentBuilders :: Int
+concurrentBuilders = 2
+
+type DesiredOutputs = M.Map JobName CommitHash
+
+type CommitHash = String
+
+type ActualOutputs = M.Map JobName CommitHash
+
+data BuildJobs = BuildJobs
+  { pendingBuilds :: M.Map JobName CommitHash,
+    runningBuilds :: M.Map JobName CommitHash
+  }
+  deriving (Show)
+
+diff :: DesiredOutputs -> ActualOutputs -> BuildJobs
+diff desiredOutputs actualOutputs =
+  BuildJobs
+    { pendingBuilds =
+        M.merge
+          M.preserveMissing
+          M.dropMissing
+          ( M.zipWithMaybeMatched
+              ( \_ actualCommit desiredCommit ->
+                  if desiredCommit /= actualCommit
+                    then Just desiredCommit
+                    else Nothing
+              )
+          )
+          desiredOutputs
+          actualOutputs,
+      runningBuilds = M.empty
+    }
+
+replaceBuildJobs :: BuildJobs -> BuildJobs -> BuildJobs
+replaceBuildJobs oldBuildJobs newBuildJobs =
+  BuildJobs
+    { pendingBuilds =
+        M.differenceWithKey
+          ( \_ pendingCommit runningCommit ->
+              if pendingCommit /= runningCommit
+                then Just pendingCommit
+                else Nothing
+          )
+          newBuildJobs.pendingBuilds
+          oldBuildJobs.runningBuilds,
+      runningBuilds = oldBuildJobs.runningBuilds
+    }
+
+data BuildJob = BuildJob
+  { jobName :: JobName,
+    commitHash :: CommitHash
+  }
+  deriving (Show)
+
+obtainBuildJob :: BuildJobs -> (Maybe BuildJob, BuildJobs)
+obtainBuildJob buildJobs = do
+  case uncurry BuildJob <$> M.lookupMin buildJobs.pendingBuilds of
+    Just buildJob@(BuildJob {jobName, commitHash}) ->
+      ( Just buildJob,
+        buildJobs
+          { pendingBuilds = M.delete jobName buildJobs.pendingBuilds,
+            runningBuilds = M.insert jobName commitHash buildJobs.runningBuilds
+          }
+      )
+    Nothing ->
+      (Nothing, buildJobs)
+
+completeBuildJob :: BuildJob -> BuildJobs -> BuildJobs
+completeBuildJob (BuildJob {jobName, commitHash}) buildJobs =
+  buildJobs
+    { runningBuilds =
+        M.filterWithKey
+          ( \jobName' commitHash' ->
+              jobName' /= jobName || commitHash' /= commitHash
+          )
+          buildJobs.runningBuilds
+    }
+
+data Builder = Builder Int
+  deriving (Show)
+
+data LogEntry = BuildEntry
+  { builder :: Builder,
+    buildJob :: BuildJob,
+    payload :: LB.ByteString
+  }
+  deriving (Show)
+
+main :: IO ()
+main = do
+  hSetBuffering stderr LineBuffering
+  hSetBuffering stdout LineBuffering
+  inotify <- initINotify
+  desiredOutputsT <- newTVarIO M.empty
+  actualOutputsT <- newTVarIO M.empty
+  buildJobsT <- newTVarIO (BuildJobs M.empty M.empty)
+  logs <- newTQueueIO
+  createDirectoryIfMissing True stateDirectory
+  setCurrentDirectory stateDirectory
+  mapM_
+    (forkIO . builder logs buildJobsT)
+    (map Builder [1 .. concurrentBuilders])
+  mapM_ (uncurry (watch inotify desiredOutputsT)) (M.toList urls)
+  _ <- forkIO (scheduler desiredOutputsT actualOutputsT buildJobsT)
+  forever do
+    log <- atomically $ readTQueue logs
+    case log of
+      BuildEntry _ (BuildJob {jobName}) (LB.toString -> payload) ->
+        printf "[%s] %s\n" jobName payload
+
+scheduler ::
+  TVar DesiredOutputs ->
+  TVar ActualOutputs ->
+  TVar BuildJobs ->
+  IO ()
+scheduler desiredOutputsT actualOutputsT buildJobsT = do
+  lastDesiredOutputsT <- newTVarIO Nothing
+  forever $ atomically do
+    lastDesiredOutputs <- readTVar lastDesiredOutputsT
+    desiredOutputs <- readTVar desiredOutputsT
+    check (Just desiredOutputs /= lastDesiredOutputs)
+    actualOutputs <- readTVar actualOutputsT
+    let buildJobs' = diff desiredOutputs actualOutputs
+    buildJobs <- readTVar buildJobsT
+    writeTVar buildJobsT (replaceBuildJobs buildJobs buildJobs')
+    writeTVar lastDesiredOutputsT (Just desiredOutputs)
+
+builder :: TQueue LogEntry -> TVar BuildJobs -> Builder -> IO ()
+builder logs buildJobsT builder =
+  forever
+    ( do
+        buildJob <- atomically do
+          buildJobs <- readTVar buildJobsT
+          let (maybeBuildJob, buildJobs') = obtainBuildJob buildJobs
+          check (isJust maybeBuildJob)
+          writeTVar buildJobsT buildJobs'
+          pure (fromJust maybeBuildJob)
+
+        build logs builder buildJob
+          `catch` ( \(e :: SomeException) -> do
+                      print e
+                  )
+    )
+
+build :: TQueue LogEntry -> Builder -> BuildJob -> IO ()
+build logs builder buildJob@(BuildJob {jobName, commitHash}) = do
+  let url = urls M.! jobName
+      rev = commitHash
+      refDir = jobName </> ref
+      tmpDir = jobName <> "-" <> rev
+  exitCodeT <- newEmptyTMVarIO
+  _ <-
+    flip forkFinally (atomically . putTMVar exitCodeT) do
+      withSystemTempDirectory tmpDir $ \tmpDir -> do
+        writeFile (tmpDir </> "default.nix") $
+          [i|
+          import
+           (fetchGit {
+              url = "#{url}";
+              ref = "#{ref}";
+              rev = "#{rev}";
+            })
+          |]
+        (LB.lines -> out) <-
+          readProcessInterleaved_
+            (setWorkingDir tmpDir "nix-build .")
+        mapM_
+          ( atomically
+              . writeTQueue logs
+              . BuildEntry builder buildJob
+          )
+          out
+        getSymbolicLinkTarget (tmpDir </> "result")
+  exitCode <- atomically $ takeTMVar exitCodeT
+  case exitCode of
+    Left e -> throw e
+    Right nixDir -> do
+      createDirectoryIfMissing True jobName
+      _ <- try @SomeException (removeDirectoryLink refDir)
+      createDirectoryLink nixDir refDir
+
+watch :: INotify -> TVar DesiredOutputs -> JobName -> Url -> IO ()
+watch inotify desiredOutputsT jobName url = do
+  let bareFp = url </> "refs/heads"
+      nonBareFp = url </> ".git/refs/heads"
+  isBare <- doesDirectoryExist bareFp
+  _ <- addWatch
+    inotify
+    [ Modify,
+      MoveIn
+    ]
+    (B.fromString (if isBare then bareFp else nonBareFp))
+    $ \e -> do
+      let isChange =
+            case e of
+              System.INotify.Modified _ (Just (B.toString -> filePath)) -> filePath == ref
+              System.INotify.MovedIn False (B.toString -> filePath) _ -> filePath == ref
+              _ -> False
+      when isChange do
+        updateDesiredOutputs
+  updateDesiredOutputs
+  where
+    updateDesiredOutputs = do
+      rev <- withRepository lgFactory url do
+        Just cid <- resolveReference ("refs/heads/" <> T.pack ref)
+        show . untag . (.commitOid) <$> lookupCommit (Tagged cid)
+      atomically do
+        desiredOutputs <- readTVar desiredOutputsT
+        writeTVar desiredOutputsT (M.insert jobName rev desiredOutputs)
diff --git a/default.nix b/default.nix
new file mode 100644
index 0000000..a602d13
--- /dev/null
+++ b/default.nix
@@ -0,0 +1,21 @@
+{ pkgs ? import <nixpkgs> { } }:
+let
+  haskellPackages = pkgs.haskellPackages.override {
+    overrides = self: super: {
+      abuilder = self.callCabal2nix "abuilder" ./. { };
+    };
+  };
+in
+rec {
+  inherit (haskellPackages) abuilder;
+  shell = haskellPackages.shellFor {
+    packages = _: [ abuilder ];
+    buildInputs = [
+      haskellPackages.cabal2nix
+      haskellPackages.cabal-install
+      haskellPackages.ormolu
+    ];
+    withHoogle = true;
+    withHaddock = true;
+  };
+}
diff --git a/shell.nix b/shell.nix
new file mode 100644
index 0000000..a6bdf20
--- /dev/null
+++ b/shell.nix
@@ -0,0 +1 @@
+(import ./. { }).shell