Merge pull request #262839 from RaitoBezarius/qemu-vm/timeout

nixos/lib/test-driver/default.nix

···
 , tesseract4
 , vde2
 , extraPythonPackages ? (_ : [])
+, nixosTests
 }:
 
 python3Packages.buildPythonApplication {
···
   ]
     ++ (lib.optionals enableOCR [ imagemagick_light tesseract4 ])
     ++ extraPythonPackages python3Packages;
+
+  passthru.tests = {
+    inherit (nixosTests.nixos-test-driver) driver-timeout;
+  };
 
   doCheck = true;
   nativeCheckInputs = with python3Packages; [ mypy ruff black ];

nixos/lib/test-driver/test_driver/__init__.py

···
         help="vlans to span by the driver",
     )
     arg_parser.add_argument(
+        "--global-timeout",
+        type=int,
+        metavar="GLOBAL_TIMEOUT",
+        action=EnvDefault,
+        envvar="globalTimeout",
+        help="Timeout in seconds for the whole test",
+    )
+    arg_parser.add_argument(
         "-o",
         "--output_directory",
         help="""The path to the directory where outputs copied from the VM will be placed.
···
         args.testscript.read_text(),
         args.output_directory.resolve(),
         args.keep_vm_state,
+        args.global_timeout,
     ) as driver:
         if args.interactive:
             history_dir = os.getcwd()

nixos/lib/test-driver/test_driver/driver.py

···
 import os
 import re
+import signal
 import tempfile
+import threading
 from contextlib import contextmanager
 from pathlib import Path
 from typing import Any, Callable, ContextManager, Dict, Iterator, List, Optional, Union
···
     vlans: List[VLan]
     machines: List[Machine]
     polling_conditions: List[PollingCondition]
+    global_timeout: int
+    race_timer: threading.Timer
 
     def __init__(
         self,
···
         tests: str,
         out_dir: Path,
         keep_vm_state: bool = False,
+        global_timeout: int = 24 * 60 * 60 * 7,
     ):
         self.tests = tests
         self.out_dir = out_dir
+        self.global_timeout = global_timeout
+        self.race_timer = threading.Timer(global_timeout, self.terminate_test)
 
         tmp_dir = get_tmp_dir()
 
···
 
     def __exit__(self, *_: Any) -> None:
         with rootlog.nested("cleanup"):
+            self.race_timer.cancel()
             for machine in self.machines:
                 machine.release()
 
···
 
     def run_tests(self) -> None:
         """Run the test script (for non-interactive test runs)"""
+        rootlog.info(
+            f"Test will time out and terminate in {self.global_timeout} seconds"
+        )
+        self.race_timer.start()
         self.test_script()
         # TODO: Collect coverage data
         for machine in self.machines:
···
         with rootlog.nested("wait for all VMs to finish"):
             for machine in self.machines:
                 machine.wait_for_shutdown()
+            self.race_timer.cancel()
+
+    def terminate_test(self) -> None:
+        # This will be usually running in another thread than
+        # the thread actually executing the test script.
+        with rootlog.nested("timeout reached; test terminating..."):
+            for machine in self.machines:
+                machine.release()
+            # As we cannot `sys.exit` from another thread
+            # We can at least force the main thread to get SIGTERM'ed.
+            # This will prevent any user who caught all the exceptions
+            # to swallow them and prevent itself from terminating.
+            os.kill(os.getpid(), signal.SIGTERM)
 
     def create_machine(self, args: Dict[str, Any]) -> Machine:
         tmp_dir = get_tmp_dir()

nixos/lib/testing-python.nix

···
     , nodes ? {}
     , testScript
     , enableOCR ? false
+    , globalTimeout ? (60 * 60)
     , name ? "unnamed"
     , skipTypeCheck ? false
       # Skip linting (mainly intended for faster dev cycles)

nixos/lib/testing/driver.nix

···
         wrapProgram $out/bin/nixos-test-driver \
           --set startScripts "''${vmStartScripts[*]}" \
           --set testScript "$out/test-script" \
+          --set globalTimeout "${toString config.globalTimeout}" \
           --set vlans '${toString vlans}' \
           ${lib.escapeShellArgs (lib.concatMap (arg: ["--add-flags" arg]) config.extraDriverArgs)}
       '';
···
       type = types.package;
       default = hostPkgs.qemu_test;
       defaultText = "hostPkgs.qemu_test";
+    };
+
+    globalTimeout = mkOption {
+      description = mdDoc ''
+        A global timeout for the complete test, expressed in seconds.
+        Beyond that timeout, every resource will be killed and released and the test will fail.
+
+        By default, we use a 1 hour timeout.
+      '';
+      type = types.int;
+      default = 60 * 60;
+      example = 10 * 60;
     };
 
     enableOCR = mkOption {

nixos/lib/testing/run.nix

···
       '';
     };
 
+    rawTestDerivation = mkOption {
+      type = types.package;
+      description = mdDoc ''
+        Unfiltered version of `test`, for troubleshooting the test framework and `testBuildFailure` in the test framework's test suite.
+        This is not intended for general use. Use `test` instead.
+      '';
+      internal = true;
+    };
+
     test = mkOption {
       type = types.package;
       # TODO: can the interactive driver be configured to access the network?
···
   };
 
   config = {
-    test = lib.lazyDerivation { # lazyDerivation improves performance when only passthru items and/or meta are used.
-      derivation = hostPkgs.stdenv.mkDerivation {
-        name = "vm-test-run-${config.name}";
+    rawTestDerivation = hostPkgs.stdenv.mkDerivation {
+      name = "vm-test-run-${config.name}";
 
-        requiredSystemFeatures = [ "kvm" "nixos-test" ];
+      requiredSystemFeatures = [ "kvm" "nixos-test" ];
 
-        buildCommand = ''
-          mkdir -p $out
+      buildCommand = ''
+        mkdir -p $out
 
-          # effectively mute the XMLLogger
-          export LOGFILE=/dev/null
+        # effectively mute the XMLLogger
+        export LOGFILE=/dev/null
 
-          ${config.driver}/bin/nixos-test-driver -o $out
-        '';
+        ${config.driver}/bin/nixos-test-driver -o $out
+      '';
 
-        passthru = config.passthru;
+      passthru = config.passthru;
 
-        meta = config.meta;
-      };
+      meta = config.meta;
+    };
+    test = lib.lazyDerivation { # lazyDerivation improves performance when only passthru items and/or meta are used.
+      derivation = config.rawTestDerivation;
       inherit (config) passthru meta;
     };
 

nixos/tests/all-tests.nix

···
     lib-extend = handleTestOn [ "x86_64-linux" "aarch64-linux" ] ./nixos-test-driver/lib-extend.nix {};
     node-name = runTest ./nixos-test-driver/node-name.nix;
     busybox = runTest ./nixos-test-driver/busybox.nix;
+    driver-timeout = pkgs.runCommand "ensure-timeout-induced-failure" {
+      failed = pkgs.testers.testBuildFailure ((runTest ./nixos-test-driver/timeout.nix).config.rawTestDerivation);
+    } ''
+      grep -F "timeout reached; test terminating" $failed/testBuildFailure.log
+      # The program will always be terminated by SIGTERM (143) if it waits for the deadline thread.
+      [[ 143 = $(cat $failed/testBuildFailure.exit) ]]
+      touch $out
+    '';
   };
 
   # NixOS vm tests and non-vm unit tests

nixos/tests/nixos-test-driver/timeout.nix

···
+{
+  name = "Test that sleep of 6 seconds fails a timeout of 5 seconds";
+  globalTimeout = 5;
+
+  nodes = {
+    machine = ({ pkgs, ... }: {
+    });
+  };
+
+  testScript = ''
+    start_all()
+    machine.wait_for_unit("multi-user.target")
+    machine.succeed("sleep 6")
+  '';
+}