fix: attribute builds to remote store for ssh-ng builds

When using remote stores via --store "ssh-ng://...", Nix reports builds
with empty host field in JSON output. Previously this was treated as
localhost. Now we detect the remote store from upload activities and
use that host for builds reporting empty host.


:house: Remote-Dev: homespace

Author: lovesegfault

lib/NOM/State.hs

@@ -262,6 +262,10 @@ data NOMState = MkNOMState
   , evaluationState :: EvalInfo
   , successTokens :: Int
   , buildsActivity :: Strict.Maybe ActivityId
+  , remoteStore :: Strict.Maybe (Host WithContext)
+  {- ^ Detected remote store from upload activities. When builds report empty
+  host but we're uploading to a remote store, builds are happening there.
+  -}
   }
   deriving stock (Show, Eq, Ord)
 
@@ -291,6 +295,7 @@ initalStateFromBuildPlatform platform = do
       MkEvalInfo{count = 0, at = 0, lastFileName = Strict.Nothing}
       0
       Strict.Nothing
+      Strict.Nothing
 
 instance Semigroup DependencySummary where
   (MkDependencySummary ls1 lm2 lm3 lm4 ls5 lm6 lm7 lm8 lm9) <> (MkDependencySummary rs1 rm2 rm3 rm4 rs5 rm6 rm7 rm8 rm9) = MkDependencySummary (ls1 <> rs1) (lm2 <> rm2) (lm3 <> rm3) (lm4 <> rm4) (ls5 <> rs5) (lm6 <> rm6) (lm7 <> rm7) (lm8 <> rm8) (lm9 <> rm9)

lib/NOM/Update.hs

@@ -263,6 +263,8 @@ processJsonMessage = \case
         now <- getNow
         pathId <- getStorePathId path
         uploading to pathId now (Just id')
+        -- Track remote store for builds that report empty host
+        when (to /= Localhost) $ assign' #remoteStore (Strict.Just to)
       JSON.Unknown | Text.isPrefixOf "querying info" startAction.text -> set_interesting
       JSON.Builds -> do
         ba <- use #buildsActivity
@@ -486,15 +488,20 @@ uploaded host pathId end =
 
 building :: Host WithContext -> Derivation -> Double -> Maybe ActivityId -> ProcessingT m ()
 building host drvName now activityId = do
+  -- When host is Localhost but we have a known remote store, use that instead.
+  -- This happens with ssh-ng builds where Nix reports empty host.
+  effectiveHost <- case host of
+    Localhost -> Strict.maybe Localhost id <$> use #remoteStore
+    _ -> pure host
   reportName <- getReportName <$> lookupDerivationInfos drvName
-  lastNeeded <- (median <=< Map.lookup (forgetProto host, reportName)) . (.buildReports) <$> get
+  lastNeeded <- (median <=< Map.lookup (forgetProto effectiveHost, reportName)) . (.buildReports) <$> get
   drvId <- lookupDerivation drvName
   updateDerivationState drvId
     $ Building
     . \case
-      Building bi -> bi & #activityId .~ Strict.toStrict activityId -- This happens with ssh-ng. After we already registered this build as started we get a second activity start event. No frome the remote host. Sadly we can not see whether a message is from the local or the remote daemon.
+      Building bi -> bi & #activityId .~ Strict.toStrict activityId -- This happens with ssh-ng. After we already registered this build as started we get a second activity start event. Now from the remote host. Sadly we can not see whether a message is from the local or the remote daemon.
       -- It would probably be better to only mark the build running on the second start message, but that probably does not work with all remote build protocols other than ssh-ng.
-      _ -> MkBuildInfo now host (Strict.toStrict lastNeeded) (Strict.toStrict activityId) ()
+      _ -> MkBuildInfo now effectiveHost (Strict.toStrict lastNeeded) (Strict.toStrict activityId) ()
 
 median :: Map a Int -> Maybe Int
 median xs = case drop ((len - 1) `div` 2) $ sort $ toList xs of