Omni/Bild: improve concurrent build logging

- Add per-namespace log files at _/var/bild-logs/<namespace>.log
- Show log path on failure instead of dumping stderr
- Use efficient single-line updates instead of full redraws
- Use cursor save/restore for reliable positioning
- Simplify status symbols (no brackets): * + ~ . x _
- Remove OutputMode distinction (no longer needed)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

1 files changed, 91 insertions, 25 deletions

diff --git a/Omni/Bild.hs b/Omni/Bild.hs
index b4da154..73141e4 100644
--- a/Omni/Bild.hs
+++ b/Omni/Bild.hs
@@ -151,16 +151,26 @@ import Omni.Namespace (Namespace (..))
 import qualified Omni.Namespace as Namespace
 import Omni.Test ((@=?))
 import qualified Omni.Test as Test
+import Rainbow (chunk, fore, red)
+import qualified Rainbow
 import qualified System.Directory as Dir
 import qualified System.Environment as Env
 import qualified System.Exit as Exit
-import System.FilePath (dropExtension, replaceExtension, takeDirectory, (</>))
+import System.FilePath (dropExtension, replaceExtension, takeDirectory, (<.>), (</>))
 import qualified System.IO as IO
 import System.IO.Unsafe (unsafePerformIO)
 import qualified System.Process as Process
 import qualified System.Timeout as Timeout
 import qualified Text.Regex.Applicative as Regex
 
+-- | Tee conduit: write to both log file and downstream
+teeLog :: Maybe IO.Handle -> Conduit.ConduitT ByteString ByteString (Conduit.ResourceT IO) ()
+teeLog Nothing = Conduit.awaitForever Conduit.yield
+teeLog (Just h) =
+  Conduit.awaitForever <| \bs -> do
+    liftIO (writeBuildLog (Just h) bs)
+    Conduit.yield bs
+
 mapConcurrentlyBounded :: Int -> (a -> IO b) -> [a] -> IO [b]
 mapConcurrentlyBounded n f xs = do
   sem <- QSemN.newQSemN n
@@ -572,11 +582,53 @@ outname = \case
   Just o -> o
   Nothing -> mempty
 
-bindir, intdir, nixdir, vardir :: FilePath
+bindir, intdir, nixdir, vardir, logdir :: FilePath
 bindir = cab </> "bin"
 intdir = cab </> "int"
 nixdir = cab </> "nix"
 vardir = cab </> "var"
+logdir = cab </> "var" </> "bild-logs"
+
+-- | Get log file path for a namespace
+logPathForNs :: Namespace -> FilePath
+logPathForNs ns = logdir </> Namespace.toPath ns <.> "log"
+
+-- | Clear log file at the start of a build
+clearBuildLog :: Namespace -> IO ()
+clearBuildLog ns = do
+  root <- getCoderoot
+  let path = root </> logPathForNs ns
+  Dir.createDirectoryIfMissing True (takeDirectory path)
+  writeFile path ""
+
+-- | Open a log file for appending, creating directories as needed
+openBuildLog :: Namespace -> IO (Maybe IO.Handle)
+openBuildLog ns = do
+  root <- getCoderoot
+  let path = root </> logPathForNs ns
+  Dir.createDirectoryIfMissing True (takeDirectory path)
+  h <- IO.openFile path IO.AppendMode
+  IO.hSetBuffering h IO.LineBuffering
+  pure (Just h)
+
+-- | Write to build log (if handle exists)
+writeBuildLog :: Maybe IO.Handle -> ByteString -> IO ()
+writeBuildLog Nothing _ = pure ()
+writeBuildLog (Just h) bs = ByteString.hPutStr h bs >> IO.hFlush h
+
+-- | Close build log
+closeBuildLog :: Maybe IO.Handle -> IO ()
+closeBuildLog Nothing = pure ()
+closeBuildLog (Just h) = IO.hClose h
+
+-- | Show where to find the build log
+showLogPath :: Namespace -> IO ()
+showLogPath ns = do
+  root <- getCoderoot
+  let path = root </> logPathForNs ns
+  Rainbow.hPutChunks IO.stderr [fore red <| chunk <| "       see " <> Text.pack path]
+  IO.hPutStrLn IO.stderr ""
+  IO.hFlush IO.stderr
 
 -- | Emulate the *nix hierarchy in the cabdir.
 createHier :: String -> IO ()
@@ -586,7 +638,8 @@ createHier root =
     [ root </> (outToPath <| Just ""),
       root </> intdir,
       root </> nixdir,
-      root </> vardir
+      root </> vardir,
+      root </> logdir
     ]
 
 -- >>> removeVersion "array-0.5.4.0-DFLKGIjfsadi"
@@ -1167,8 +1220,8 @@ test loud Target {..} =
             cmd = root </> outToPath out,
             args = ["test"],
             ns = namespace,
-            onFailure = loud ?: (Log.fail ["test", nschunk namespace] >> Log.br, LogC.updateLineState namespace LogC.Failed),
-            onSuccess = loud ?: (Log.pass ["test", nschunk namespace] >> Log.br, LogC.updateLineState namespace LogC.Success)
+            onFailure = loud ?: (pure (), LogC.updateLineState namespace LogC.Failed),
+            onSuccess = loud ?: (pure (), LogC.updateLineState namespace LogC.Success)
           }
           |> run
       CPython ->
@@ -1177,8 +1230,8 @@ test loud Target {..} =
             cmd = root </> outToPath out,
             args = ["test"],
             ns = namespace,
-            onFailure = loud ?: (Log.fail ["test", nschunk namespace] >> Log.br, LogC.updateLineState namespace LogC.Failed),
-            onSuccess = loud ?: (Log.pass ["test", nschunk namespace] >> Log.br, LogC.updateLineState namespace LogC.Success)
+            onFailure = loud ?: (pure (), LogC.updateLineState namespace LogC.Failed),
+            onSuccess = loud ?: (pure (), LogC.updateLineState namespace LogC.Success)
           }
           |> run
       _ ->
@@ -1384,6 +1437,8 @@ promoteWaiters Coordinator {..} completedNs = do
 pipelineBuildOne :: Bool -> Bool -> Bool -> Int -> Int -> Target -> IO Exit.ExitCode
 pipelineBuildOne andTest loud andCache jobs cpus target@Target {..} = do
   root <- getCoderoot
+  -- Clear log file at the start of each build
+  unless loud (clearBuildLog namespace)
   result <- case compiler of
     CPython -> case out of
       Just _ ->
@@ -1441,10 +1496,10 @@ cacheStorePath :: Bool -> Namespace -> FilePath -> IO ()
 cacheStorePath loud ns storePath = do
   mKeyPath <- Env.lookupEnv "NIX_CACHE_KEY"
   case mKeyPath of
-    Nothing -> Log.warn ["cache", "NIX_CACHE_KEY not set, skipping"]
+    Nothing -> loud ?| Log.warn ["cache", "NIX_CACHE_KEY not set, skipping"]
     Just keyPath -> do
       let s3Url = "s3://omni-nix-cache?profile=digitalocean&scheme=https&endpoint=nyc3.digitaloceanspaces.com"
-      LogC.updateLine ns "signing..."
+      loud ?: (pure (), LogC.updateLine ns "signing...")
       (signExit, _, signErr) <-
         Process.readProcessWithExitCode
           "nix"
@@ -1452,7 +1507,7 @@ cacheStorePath loud ns storePath = do
           ""
       case signExit of
         Exit.ExitSuccess -> do
-          LogC.updateLine ns "pushing to cache..."
+          loud ?: (pure (), LogC.updateLine ns "pushing to cache...")
           (pushExit, _, pushErr) <-
             Process.readProcessWithExitCode
               "nix"
@@ -1460,14 +1515,14 @@ cacheStorePath loud ns storePath = do
               ""
           case pushExit of
             Exit.ExitSuccess -> do
-              loud ?| Log.good ["cache", "pushed", Text.pack storePath]
-              Text.IO.putStrLn <| "STORE_PATH=" <> Text.pack storePath
+              -- Only print STORE_PATH in loud mode to avoid interfering with line manager
+              loud ?: (Text.IO.putStrLn <| "STORE_PATH=" <> Text.pack storePath, pure ())
             Exit.ExitFailure _ -> do
-              Log.fail ["cache", "push failed", Text.pack storePath]
-              loud ?| putStrLn pushErr
+              -- Write error to log file, show path in normal mode
+              loud ?: (Log.fail ["cache", "push failed", Text.pack storePath] >> putStrLn pushErr, showLogPath ns)
         Exit.ExitFailure _ -> do
-          Log.fail ["cache", "sign failed", Text.pack storePath]
-          loud ?| putStrLn signErr
+          -- Write error to log file, show path in normal mode
+          loud ?: (Log.fail ["cache", "sign failed", Text.pack storePath] >> putStrLn signErr, showLogPath ns)
 
 pipelineBuild :: Bool -> Bool -> Bool -> Int -> Int -> Int -> [Namespace] -> (Namespace -> IO (Maybe Target)) -> IO [Exit.ExitCode]
 pipelineBuild andTest loud andCache analysisWorkers buildWorkers cpus namespaces analyzeFn = do
@@ -1505,24 +1560,35 @@ run :: Proc -> IO (Exit.ExitCode, ByteString)
 run Proc {..} = do
   IO.hSetBuffering stdout IO.NoBuffering
   loud ?| Log.info ["proc", unwords <| map str <| cmd : args]
+
+  -- Open log file for this build (skip if loud mode)
+  logHandle <- if loud then pure Nothing else openBuildLog ns
+
   Conduit.proc cmd args
     |> (\proc_ -> proc_ {Process.create_group = True})
     |> Conduit.streamingProcess
     +> \(stdin_, stdout_, stderr_, hdl) -> do
       IO.hClose stdin_ -- Close stdin immediately since we don't use it
+
+      -- Insert teeLog to write to file while streaming
+      let stdoutWithLog = stdout_ .| teeLog logHandle
+      let stderrWithLog = stderr_ .| teeLog logHandle
+
       (,,)
         </ Async.Concurrently (Conduit.waitForStreamingProcess hdl)
-        <*> Async.Concurrently (loud ?: (puts stdout_, logs ns stdout_))
-        <*> Async.Concurrently (loud ?: (puts stderr_, logs ns stderr_))
+        <*> Async.Concurrently (loud ?: (puts stdoutWithLog, logs ns stdoutWithLog))
+        <*> Async.Concurrently (loud ?: (puts stderrWithLog, logs ns stderrWithLog))
         |> Async.runConcurrently
         +> \case
           (Exit.ExitFailure n, output, outerr) ->
-            Conduit.closeStreamingProcessHandle hdl
-              >> putStr outerr
+            closeBuildLog logHandle
+              >> Conduit.closeStreamingProcessHandle hdl
+              >> (loud ?: (putStr outerr, showLogPath ns))
               >> onFailure
               >> pure (Exit.ExitFailure n, output)
           (Exit.ExitSuccess, output, _) ->
-            Conduit.closeStreamingProcessHandle hdl
+            closeBuildLog logHandle
+              >> Conduit.closeStreamingProcessHandle hdl
               >> onSuccess
               >> pure (Exit.ExitSuccess, output)
 
@@ -1539,7 +1605,7 @@ proc loud namespace cmd args =
       ns = namespace,
       cmd = cmd,
       args = map Text.unpack args,
-      onFailure = Log.fail ["bild", nschunk namespace] >> Log.br,
+      onFailure = pure (), -- Let run() handle failure display
       onSuccess = pure ()
     }
     |> run
@@ -1639,7 +1705,7 @@ nixBuild loud maxJobs cores target@(Target {..}) =
             ]
               |> mconcat
               |> map Text.unpack,
-          onFailure = Log.fail ["bild", "instantiate", nschunk namespace] >> Log.br,
+          onFailure = pure (), -- Let run() handle failure display
           onSuccess = pure ()
         }
     realise drv =
@@ -1657,7 +1723,7 @@ nixBuild loud maxJobs cores target@(Target {..}) =
               "--cores",
               str cores
             ],
-          onFailure = Log.fail ["bild", "realise", nschunk namespace] >> Log.br,
+          onFailure = pure (), -- Let run() handle failure display
           onSuccess = pure ()
         }
     symlink =
@@ -1672,7 +1738,7 @@ nixBuild loud maxJobs cores target@(Target {..}) =
               nixdir </> outname out </> "bin" </> outname out,
               bindir </> outname out
             ],
-          onFailure = Log.fail ["bild", "symlink", nschunk namespace] >> Log.br,
+          onFailure = pure (), -- Let run() handle failure display
           onSuccess = pure ()
         }