From 388a54929a343382c850a4674d7396a3a8b81518 Mon Sep 17 00:00:00 2001
From: Arian van Putten <arian.vanputten@gmail.com>
Date: Thu, 3 Apr 2025 01:40:10 +0100
Subject: [PATCH] nixos/tests/fluent-bit: add regression test for #395128

---
 nixos/tests/fluent-bit.nix | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/nixos/tests/fluent-bit.nix b/nixos/tests/fluent-bit.nix
index 9dc68011ea85..729a586784ad 100644
--- a/nixos/tests/fluent-bit.nix
+++ b/nixos/tests/fluent-bit.nix
@@ -13,7 +13,7 @@ import ./make-test-python.nix (
               inputs = [
                 {
                   name = "systemd";
-                  systemd_filter = "_SYSTEMD_UNIT=fluent-bit.service";
+                  systemd_filter = "_SYSTEMD_UNIT=fluent-bit-regression-395128.service";
                 }
               ];
               outputs = [
@@ -28,12 +28,35 @@ import ./make-test-python.nix (
         };
 
         systemd.services.fluent-bit.serviceConfig.LogsDirectory = "fluent-bit";
+
+        # Logs get compressed when larger than 1024 bytes
+        # Lets generate some logs that trigger that
+        # This causes libzstd to be dlopen'd by systemd which breaks fluent-bit 3.2.7+
+        # https://www.freedesktop.org/software/systemd/man/latest/journald.conf.html#Compress=
+        systemd.services.fluent-bit-regression-395128 = {
+          serviceConfig = {
+            Type = "oneshot";
+            RemainAfterExit = true;
+          };
+          script = ''
+            for i in {1..20}; do
+              (head -c 1200 < /dev/zero | tr '\0' 'A') && echo
+              sleep 1
+            done
+          '';
+        };
       };
 
     testScript = ''
       start_all()
 
       machine.wait_for_unit("fluent-bit.service")
+
+      # Regression test for https://github.com/NixOS/nixpkgs/pull/395128
+      with subtest("fluent-bit handles zstd-compressed journal logs"):
+        machine.succeed("systemctl start fluent-bit-regression-395128.service")
+        machine.succeed("systemctl show -p NRestarts fluent-bit.service | grep -q 'NRestarts=0'")
+
       machine.wait_for_file("/var/log/fluent-bit/fluent-bit.out")
     '';
   }