From ebc924d4925093a551fa5fd888bb24205f7c6177 Mon Sep 17 00:00:00 2001
From: Florian Klink <flokli@flokli.de>
Date: Tue, 18 Mar 2025 00:45:26 +0000
Subject: [PATCH] tests(tvix/nix-daemon): add a test suite for tvix nix-daemon

This uses runInLinuxVM to seed tvix-store with a path/closure, then sets
up a local-overlay store mount config using the following setup:

/tmp/tvix exposes everything seeded into tvix
/tmp/scratch represents an empty "local" nix store

This is overlayed to /tmp/merged/nix/store
(using /tmp/work as an overlayfs work dir).

Nix is configured with the local-overlay feature:
 - setting /tmp/merged as root
 - configuring a unix:///tmp/tvix-daemon.sock as lower store,
   with lower-store.real set to /tmp/tvix
 - configuring /tmp/scratch as an upper layer

For some reasons, check-mount needs to be set to false, as Nix doesn't
seem happy with the way we set up the mountpoints.

Change-Id: I03e1cf1d3aaa021a63dcb30ae482a6c3977851ba
Reviewed-on: https://cl.snix.dev/c/snix/+/30087
Reviewed-by: Vova Kryachko <v.kryachko@gmail.com>
Reviewed-by: Ilan Joselevich <personal@ilanjoselevich.com>
Tested-by: besadii
---
 snix/nix-daemon/tests/default.nix | 118 ++++++++++++++++++++++++++++++
 1 file changed, 118 insertions(+)
 create mode 100644 snix/nix-daemon/tests/default.nix

diff --git a/snix/nix-daemon/tests/default.nix b/snix/nix-daemon/tests/default.nix
new file mode 100644
index 000000000..186cdab79
--- /dev/null
+++ b/snix/nix-daemon/tests/default.nix
@@ -0,0 +1,118 @@
+{ depot
+, pkgs
+, lib
+, ...
+}:
+
+let
+  mkTest =
+    { closure
+    , blobServiceAddr ? "objectstore+file:///tmp/blobs"
+    , directoryServiceAddr ? "redb:///tmp/directories.redb"
+    , pathInfoServiceAddr ? "redb:///tmp/pathinfo.redb"
+    , testScript
+    , # FUTUREWORK: make overlay setup configurable for non-local-overlay tests?
+    }:
+
+    pkgs.vmTools.runInLinuxVM (
+      (pkgs.runCommand "test-script"
+        {
+          nativeBuildInputs = [
+            pkgs.util-linux # mount, mountpoint
+            depot.third_party.nixpkgs.nixVersions.stable
+            depot.snix.store
+          ];
+          __structuredAttrs = true;
+          exportReferencesGraph.closure = [ closure ];
+        }
+        (
+          ''
+            touch $out
+            # Ensure we can construct http clients.
+            export SSL_CERT_FILE=/dev/null
+
+            # Start the snix daemon, listening on a unix socket.
+            BLOB_SERVICE_ADDR=${lib.escapeShellArg blobServiceAddr} \
+            DIRECTORY_SERVICE_ADDR=${lib.escapeShellArg directoryServiceAddr} \
+            PATH_INFO_SERVICE_ADDR=${lib.escapeShellArg pathInfoServiceAddr} \
+              snix-store \
+                --otlp=false \
+                daemon -l $PWD/snix-store.sock &
+
+            # Wait for the service to report healthy.
+            timeout 22 sh -c "until ${pkgs.ip2unix}/bin/ip2unix -r out,path=$PWD/snix-store.sock ${pkgs.grpc-health-check}/bin/grpc-health-check --address 127.0.0.1 --port 8080; do sleep 1; done"
+
+            # Export env vars so that subsequent snix-store commands will talk to
+            # our snix-store daemon over the unix socket.
+            export BLOB_SERVICE_ADDR=grpc+unix://$PWD/snix-store.sock
+            export DIRECTORY_SERVICE_ADDR=grpc+unix://$PWD/snix-store.sock
+            export PATH_INFO_SERVICE_ADDR=grpc+unix://$PWD/snix-store.sock
+
+            echo "Copying closure ${closure}…"
+            # This picks up the `closure` key in `$NIX_ATTRS_JSON_FILE` automatically.
+            snix-store --otlp=false copy 2> /dev/null # noisy progress bars
+
+            # Create mountpoints
+            # For this test, we overlay a (treated read-only) snix-provided mountpoint
+            # with a read-writeable scratch space.
+            # It is exposed at /tmp/merged/nix/store.
+            mkdir -p /tmp/snix /tmp/scratch /tmp/work /tmp/merged/nix/store
+
+            snix-store --otlp=false mount -l /tmp/snix --allow-other &
+            # FUTUREWORK: add snix-store mount "forking to background" option
+            timeout 22 sh -c 'until mountpoint -q /tmp/snix; do sleep 0.5; done'
+
+            mount -t overlay overlay -o lowerdir=/tmp/snix -o workdir=/tmp/work -o upperdir=/tmp/scratch /tmp/merged/nix/store
+
+            # Run the Snix nix-daemon
+            RUST_LOG=nix_daemon=debug ${depot.snix.nix-daemon}/bin/nix-daemon --otlp=false --unix-listen-unlink --unix-listen-chmod everybody &
+            timeout 22 sh -c 'until [ -e /tmp/snix-daemon.sock ]; do sleep 1; done'
+
+            # Run the test script
+            ${testScript}
+          ''
+        )
+      ).overrideAttrs
+        (_: {
+          memSize = 4096;
+        })
+    );
+  closure = pkgs.hello;
+  localOverlayStoreConfig = "local-overlay://?root=/tmp/merged&lower-store=unix%3A%2F%2F%2Ftmp%2Fsnix-daemon.sock&lower-store.real%3D%2Ftmp%2Fsnix&upper-layer=/tmp/scratch&check-mount=false";
+in
+{
+  nixstoreQr = (
+    mkTest {
+      inherit closure;
+      testScript = ''
+        nix-store -qR ${closure} \
+          --store "${localOverlayStoreConfig}" --extra-experimental-features 'local-overlay-store'
+      '';
+    }
+  );
+  pathInfo = (
+    mkTest {
+      inherit closure;
+      testScript = ''
+        nix path-info --json --closure-size --recursive ${closure} \
+          --store "${localOverlayStoreConfig}" --extra-experimental-features 'local-overlay-store nix-command'
+      '';
+    }
+  );
+  /*
+    This currently cannot work as our store is not mounted at /nix/store but at another location, and since nix-shell
+    needs bash it fails with `unable to exec /nix/store/xxx-bash/bin/bash`, to run shell we need to chroot to have the 
+    overlay store at /nix/store.
+  */
+  shell = (
+    mkTest {
+      inherit closure;
+      testScript = ''
+        nix shell ${pkgs.hello} \
+          --store "${localOverlayStoreConfig}" --extra-experimental-features 'local-overlay-store nix-command'
+      '';
+    }
+  );
+
+  meta.ci.targets = [ "nixstoreQr" "pathInfo" ];
+}