Merge pull request #1647 from obsidiansystems/prepare-for-queue-runner-redirected-store

Prepare for queue runner redirected store

Author: Ericson2314

subprojects/crates/nix-utils/include/nix.h

@@ -70,6 +70,7 @@ void nar_from_path(const StoreWrapper &src_store, rust::Str path,
 rust::String list_nar_deep(const StoreWrapper &wrapper, rust::Str path);
 
 void ensure_path(const StoreWrapper &wrapper, rust::Str path);
+rust::String to_real_path(const StoreWrapper &wrapper, rust::Str path);
 rust::String write_derivation(const StoreWrapper &wrapper, rust::Str json);
 rust::Vec<DerivationHash> static_output_hashes(const StoreWrapper &wrapper,
                                                rust::Str output_path);

subprojects/crates/nix-utils/src/drv.rs

@@ -34,12 +34,12 @@ pub async fn query_drv(
         return Ok(None);
     }
 
-    let full_path = store.print_store_path(drv);
-    if !fs_err::tokio::try_exists(&full_path).await? {
+    if !store.is_valid_path(drv).await {
         return Ok(None);
     }
 
-    let input = fs_err::tokio::read_to_string(&full_path).await?;
+    let real_path = store.to_real_path(drv).await?;
+    let input = fs_err::tokio::read_to_string(&real_path).await?;
     Ok(Some(parse_drv(store.get_store_dir(), drv, &input)?))
 }
 

subprojects/crates/nix-utils/src/lib.rs

@@ -213,6 +213,7 @@ mod ffi {
         fn list_nar_deep(store: &StoreWrapper, path: &str) -> Result<String>;
 
         fn ensure_path(store: &StoreWrapper, path: &str) -> Result<()>;
+        fn to_real_path(store: &StoreWrapper, path: &str) -> Result<String>;
         fn write_derivation(store: &StoreWrapper, json: &str) -> Result<String>;
         fn static_output_hashes(
             store: &StoreWrapper,
@@ -883,6 +884,17 @@ impl LocalStore {
         })
         .await
     }
+
+    /// Resolve a store path to its physical filesystem location.
+    ///
+    /// For stores where the physical store directory differs from the
+    /// logical `storeDir` (e.g. `local?root=X&store=Y`), this returns the
+    /// actual on-disk path rather than the logical store path.
+    pub async fn to_real_path(&self, path: &StorePath) -> Result<String, Error> {
+        let printed = self.base.store_dir.display(path).to_string();
+        let store = self.base.wrapper.clone();
+        asyncify(move || ffi::to_real_path(store.as_raw(), &printed)).await
+    }
 }
 
 impl BaseStore for LocalStore {

subprojects/crates/nix-utils/src/nix.cpp

@@ -6,6 +6,7 @@
 #include <string.h>
 
 #include <nix/store/derivations.hh>
+#include <nix/store/local-fs-store.hh>
 #include <nix/store/remote-store.hh>
 #include <nix/store/store-api.hh>
 #include <nix/store/store-open.hh>
@@ -324,6 +325,19 @@ void ensure_path(const StoreWrapper &wrapper, rust::Str path) {
   store->ensurePath(store->followLinksToStorePath(AS_VIEW(path)));
 }
 
+rust::String to_real_path(const StoreWrapper &wrapper, rust::Str path) {
+  auto store = wrapper._store;
+  auto *lfs = dynamic_cast<nix::LocalFSStore *>(&*store);
+  if (!lfs) {
+    throw nix::Error(
+        "toRealPath: store '%s' is not a local filesystem store",
+        store->config.getHumanReadableURI());
+  }
+  auto storePath = store->parseStorePath(AS_VIEW(path));
+  auto s = lfs->toRealPath(storePath).string();
+  return rust::String(s.data(), s.size());
+}
+
 rust::String write_derivation(const StoreWrapper &wrapper, rust::Str json) {
   auto store = wrapper._store;
   auto drv = nix::Derivation::parseJsonAndValidate(

subprojects/hydra/lib/Hydra/Helper/Nix.pm

@@ -141,7 +141,17 @@ sub gcRootFor {
 sub registerRoot {
     my ($path) = @_;
     my $link = gcRootFor $path;
-    return if -e $link;
+    # A pre-existing symlink (e.g. from nix-eval-jobs --gc-roots-dir) may
+    # point at a logical store path whose physical location is elsewhere,
+    # so `-e` would return false even though the target is a valid store
+    # object. Read the symlink and ask the store whether the target is
+    # valid, rather than testing the path on this filesystem.
+    if (-l $link) {
+        my $target = readlink $link;
+        return if defined $target && $MACHINE_LOCAL_STORE->isValidPath($target);
+        # Stale symlink: remove it so we can replace it below.
+        unlink $link;
+    }
     open(my $root, ">", $link) or die "cannot create GC root `$link' to `$path'";
     close $root;
 }

subprojects/hydra/script/hydra-eval-jobset

@@ -665,8 +665,13 @@ sub checkJobsetWrapped {
         die "multiple alternatives for the input containing the declarative project specification are not supported\n"
             if scalar @declInputs != 1;
         my $declFile = $declInput->{storePath} . "/" . $project->declfile;
-        my $declText = read_text($declFile)
-            or die "Couldn't read declarative specification file $declFile: $!\n";
+        # Use `nix store cat` so the physical store location is resolved
+        # by the store itself (handles root= stores where physical != logical).
+        my ($res, $declText, $catErr) = captureStdoutStderr(
+            60,
+            "nix", "--extra-experimental-features", "nix-command",
+            "store", "cat", $declFile);
+        die "Couldn't read declarative specification file $declFile: $catErr\n" if $res != 0;
         my $declSpec;
         eval {
             $declSpec = decode_json($declText);