nixpkgs/nixos/lib/testing-python.nix
Maximilian Bosch 1ba3f7927f
nixos/testing: only create nixos-run-vms for nixos-build-vms(8)
This is the case when the test-script is empty. `nixos-build-vms(8)` is
primarily supposed to be used as tool to test changes or to reproduce
bugs (IMHO) where "just spinning up a few VMs" is the primary use-case.

In the ongoing discussion about these changes[1] it was suggested to
only expose it when needed (i.e. in the case I described above) to keep
the API surface as slim as possible.

[1] https://github.com/NixOS/nixpkgs/pull/133675#discussion_r688112485
2021-08-13 17:39:49 +02:00

361 lines
11 KiB
Nix

{ system
, pkgs ? import ../.. { inherit system config; }
# Use a minimal kernel?
, minimal ? false
# Ignored
, config ? { }
# !!! See comment about args in lib/modules.nix
, specialArgs ? { }
# Modules to add to each VM
, extraConfigurations ? [ ]
}:
with pkgs;
rec {
inherit pkgs;
# Reifies and correctly wraps the python test driver for
# the respective qemu version and with or without ocr support
pythonTestDriver = {
qemu_pkg ? pkgs.qemu_test
, enableOCR ? false
}:
let
name = "nixos-test-driver";
testDriverScript = ./test-driver/test-driver.py;
ocrProg = tesseract4.override { enableLanguages = [ "eng" ]; };
imagemagick_tiff = imagemagick_light.override { inherit libtiff; };
in stdenv.mkDerivation {
inherit name;
nativeBuildInputs = [ makeWrapper ];
buildInputs = [ (python3.withPackages (p: [ p.ptpython p.colorama ])) ];
checkInputs = with python3Packages; [ pylint black mypy ];
dontUnpack = true;
preferLocalBuild = true;
buildPhase = ''
python <<EOF
from pydoc import importfile
with open('driver-symbols', 'w') as fp:
fp.write(','.join(dir(importfile('${testDriverScript}'))))
EOF
'';
doCheck = true;
checkPhase = ''
mypy --disallow-untyped-defs \
--no-implicit-optional \
--ignore-missing-imports ${testDriverScript}
pylint --errors-only ${testDriverScript}
black --check --diff ${testDriverScript}
'';
installPhase =
''
mkdir -p $out/bin
cp ${testDriverScript} $out/bin/nixos-test-driver
chmod u+x $out/bin/nixos-test-driver
# TODO: copy user script part into this file (append)
wrapProgram $out/bin/nixos-test-driver \
--argv0 ${name} \
--prefix PATH : "${lib.makeBinPath [ qemu_pkg vde2 netpbm coreutils socat ]}" \
${lib.optionalString enableOCR
"--prefix PATH : '${ocrProg}/bin:${imagemagick_tiff}/bin'"} \
install -m 0644 -vD driver-symbols $out/nix-support/driver-symbols
'';
};
# Run an automated test suite in the given virtual network.
runTests = { driver, pos }:
stdenv.mkDerivation {
name = "vm-test-run-${driver.testName}";
requiredSystemFeatures = [ "kvm" "nixos-test" ];
buildCommand =
''
mkdir -p $out
# effectively mute the XMLLogger
export LOGFILE=/dev/null
${driver}/bin/nixos-test-driver
'';
passthru = driver.passthru // {
inherit driver;
};
inherit pos; # for better debugging
};
# Generate convenience wrappers for running the test driver
# has vlans, vms and test script defaulted through env variables
# also instantiates test script with nodes, if it's a function (contract)
setupDriverForTest = {
testScript
, testName
, nodes
, qemu_pkg ? pkgs.qemu_test
, enableOCR ? false
, skipLint ? false
, passthru ? {}
}:
let
# FIXME: get this pkg from the module system
testDriver = pythonTestDriver { inherit qemu_pkg enableOCR;};
testDriverName =
let
# A standard store path to the vm monitor is built like this:
# /tmp/nix-build-vm-test-run-$name.drv-0/vm-state-machine/monitor
# The max filename length of a unix domain socket is 108 bytes.
# This means $name can at most be 50 bytes long.
maxTestNameLen = 50;
testNameLen = builtins.stringLength testName;
in with builtins;
if testNameLen > maxTestNameLen then
abort
("The name of the test '${testName}' must not be longer than ${toString maxTestNameLen} " +
"it's currently ${toString testNameLen} characters long.")
else
"nixos-test-driver-${testName}";
vlans = map (m: m.config.virtualisation.vlans) (lib.attrValues nodes);
vms = map (m: m.config.system.build.vm) (lib.attrValues nodes);
nodeHostNames = map (c: c.config.system.name) (lib.attrValues nodes);
# TODO: This is an implementation error and needs fixing
# the testing famework cannot legitimately restrict hostnames further
# beyond RFC1035
invalidNodeNames = lib.filter
(node: builtins.match "^[A-z_]([A-z0-9_]+)?$" node == null)
nodeHostNames;
testScript' =
# Call the test script with the computed nodes.
if lib.isFunction testScript
then testScript { inherit nodes; }
else testScript;
in
if lib.length invalidNodeNames > 0 then
throw ''
Cannot create machines out of (${lib.concatStringsSep ", " invalidNodeNames})!
All machines are referenced as python variables in the testing framework which will break the
script when special characters are used.
This is an IMPLEMENTATION ERROR and needs to be fixed. Meanwhile,
please stick to alphanumeric chars and underscores as separation.
''
else lib.warnIf skipLint "Linting is disabled" (runCommand testDriverName
{
inherit testName;
nativeBuildInputs = [ makeWrapper ];
testScript = testScript';
preferLocalBuild = true;
passthru = passthru // {
inherit nodes;
};
}
''
mkdir -p $out/bin
vmStartScripts=($(for i in ${toString vms}; do echo $i/bin/run-*-vm; done))
echo -n "$testScript" > $out/test-script
ln -s ${testDriver}/bin/nixos-test-driver $out/bin/nixos-test-driver
${lib.optionalString (!skipLint) ''
PYFLAKES_BUILTINS="$(
echo -n ${lib.escapeShellArg (lib.concatStringsSep "," nodeHostNames)},
< ${lib.escapeShellArg "${testDriver}/nix-support/driver-symbols"}
)" ${python3Packages.pyflakes}/bin/pyflakes $out/test-script
''}
# set defaults through environment
# see: ./test-driver/test-driver.py argparse implementation
wrapProgram $out/bin/nixos-test-driver \
--set startScripts "''${vmStartScripts[*]}" \
--set testScript "$out/test-script" \
--set vlans '${toString vlans}'
${lib.optionalString (testScript == "") ''
ln -s ${testDriver}/bin/nixos-test-driver $out/bin/nixos-run-vms
wrapProgram $out/bin/nixos-run-vms \
--set startScripts "''${vmStartScripts[*]}" \
--set testScript "${pkgs.writeText "start-all" "start_all(); join_all();"}" \
--set vlans '${toString vlans}'
''}
'');
# Make a full-blown test
makeTest =
{ testScript
, enableOCR ? false
, name ? "unnamed"
# Skip linting (mainly intended for faster dev cycles)
, skipLint ? false
, passthru ? {}
, # For meta.position
pos ? # position used in error messages and for meta.position
(if t.meta.description or null != null
then builtins.unsafeGetAttrPos "description" t.meta
else builtins.unsafeGetAttrPos "testScript" t)
, ...
} @ t:
let
nodes = qemu_pkg:
let
build-vms = import ./build-vms.nix {
inherit system pkgs minimal specialArgs;
extraConfigurations = extraConfigurations ++ [(
{
virtualisation.qemu.package = qemu_pkg;
# Ensure we do not use aliases. Ideally this is only set
# when the test framework is used by Nixpkgs NixOS tests.
nixpkgs.config.allowAliases = false;
}
)];
};
in
build-vms.buildVirtualNetwork (
t.nodes or (if t ? machine then { machine = t.machine; } else { })
);
driver = setupDriverForTest {
inherit testScript enableOCR skipLint passthru;
testName = name;
qemu_pkg = pkgs.qemu_test;
nodes = nodes pkgs.qemu_test;
};
driverInteractive = setupDriverForTest {
inherit testScript enableOCR skipLint passthru;
testName = name;
qemu_pkg = pkgs.qemu;
nodes = nodes pkgs.qemu;
};
test =
let
passMeta = drv: drv // lib.optionalAttrs (t ? meta) {
meta = (drv.meta or { }) // t.meta;
};
in passMeta (runTests { inherit driver pos; });
in
test // {
inherit test driver driverInteractive nodes;
};
runInMachine =
{ drv
, machine
, preBuild ? ""
, postBuild ? ""
, qemu_pkg ? pkgs.qemu_test
, ... # ???
}:
let
build-vms = import ./build-vms.nix {
inherit system pkgs minimal specialArgs extraConfigurations;
};
vm = build-vms.buildVM { }
[
machine
{
key = "run-in-machine";
networking.hostName = "client";
nix.readOnlyStore = false;
virtualisation.writableStore = false;
}
];
buildrunner = writeText "vm-build" ''
source $1
${coreutils}/bin/mkdir -p $TMPDIR
cd $TMPDIR
exec $origBuilder $origArgs
'';
testScript = ''
start_all()
client.wait_for_unit("multi-user.target")
${preBuild}
client.succeed("env -i ${bash}/bin/bash ${buildrunner} /tmp/xchg/saved-env >&2")
${postBuild}
client.succeed("sync") # flush all data before pulling the plug
'';
testDriver = pythonTestDriver { inherit qemu_pkg; };
vmRunCommand = writeText "vm-run" ''
xchg=vm-state-client/xchg
${coreutils}/bin/mkdir $out
${coreutils}/bin/mkdir -p $xchg
for i in $passAsFile; do
i2=''${i}Path
_basename=$(${coreutils}/bin/basename ''${!i2})
${coreutils}/bin/cp ''${!i2} $xchg/$_basename
eval $i2=/tmp/xchg/$_basename
${coreutils}/bin/ls -la $xchg
done
unset i i2 _basename
export | ${gnugrep}/bin/grep -v '^xchg=' > $xchg/saved-env
unset xchg
export tests='${testScript}'
${testDriver}/bin/nixos-test-driver --keep-vm-state ${vm.config.system.build.vm}/bin/run-*-vm
''; # */
in
lib.overrideDerivation drv (attrs: {
requiredSystemFeatures = [ "kvm" ];
builder = "${bash}/bin/sh";
args = [ "-e" vmRunCommand ];
origArgs = attrs.args;
origBuilder = attrs.builder;
});
runInMachineWithX = { require ? [ ], ... } @ args:
let
client =
{ ... }:
{
inherit require;
imports = [
../tests/common/auto.nix
];
virtualisation.memorySize = 1024;
services.xserver.enable = true;
test-support.displayManager.auto.enable = true;
services.xserver.displayManager.defaultSession = "none+icewm";
services.xserver.windowManager.icewm.enable = true;
};
in
runInMachine ({
machine = client;
preBuild =
''
client.wait_for_x()
'';
} // args);
simpleTest = as: (makeTest as).test;
}