Re: [PATCH] run: introduce a script for running devel commands

[John Snow <jsnow@redhat.com>]

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On Wed, Dec 10, 2025, 11:05 AM Daniel P. Berrangé <berrange@redhat.com>
wrote:

> Various aspects of the development workflow are complicated by the need
> to set env variables ahead of time, or use specific paths. Introduce a
> $BUILD_DIR/run script that will do a number of things
>
>  * Set $PATH to point to $BUILD_DIR/qemu-bundle/$PREFIX/$BIN_DIR
>  * Set $PYTHONPATH to point to $SRC_DIR/tests/functional
>  * Source $BUILD_DIR/pyvenv/bin/activate
>
> To see the benefits of this consider this command:
>
>   $ source ./build/pyvenv/bin/activate
>   $ ./scripts/qmp/qmp-shell-wrap ./build/qemu-system-x86_64
>
> which is now simplified to
>
>   $ ./build/run ./scripts/qmp/qmp-shell-wrap qemu-system-x86_64 [args..]
>
> This avoids the need repeat './build' several times and avoids polluting
> the current terminal's environment and/or avoids errors from forgetting
> to source the venv settings.
>
> As another example running functional tests
>
>   $ export PYTHONPATH=./python:./tests/functional
>   $ export QEMU_TEST_QEMU_BINARY=./build/qemu-system-x86_64
>   $ build/pyvenv/bin/python3
> ./tests/functional/x86_64/test_virtio_version.py
>
> which is now simplified to
>
>   $ export QEMU_TEST_QEMU_BINARY=qemu-system-x86_64
>   $ ./build/run ./tests/functional/x86_64/test_virtio_version.py
>
> This usefulness of this will be further enhanced with the pending
> removal of the QEMU python APIs from git, as that will require the use
> of the python venv in even more scenarios that today.
>

Sounds good to me.


> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
>
> Historical context: this 'run' script concept is something introduced
> by libguestfs a decade & a half ago, and copied by libvirt shortly
> after that. It has been very helpful in simplifying life for developers
> and should do likewise for QEMU.
>
>  docs/devel/build-system.rst       | 12 ++++++++++++
>  docs/devel/testing/functional.rst | 17 ++++++++---------
>  meson.build                       | 11 +++++++++++
>  run.in                            | 15 +++++++++++++++
>  4 files changed, 46 insertions(+), 9 deletions(-)
>  create mode 100644 run.in
>
> diff --git a/docs/devel/build-system.rst b/docs/devel/build-system.rst
> index 6204aa6a72..8ec8d20175 100644
> --- a/docs/devel/build-system.rst
> +++ b/docs/devel/build-system.rst
> @@ -515,6 +515,18 @@ generates ``Makefile`` from ``Makefile.in``.
>
>  Built by configure:
>
> +``run``
> +  Used to run commands / scripts from the git checkout. Sets ``$PATH``
> +  to point to locally built binaries & activates the python venv before
> +  running the requested command. Pass the command to run as args, for
> +  example::
> +
> +    $ ./build/run ./script/qmp/qmp-shell-wrap qemu-system-x86_64
> +
> +  will use the ``python3`` binary and site-packages from the local
> +  venv to run ``qmp-shell-wrap`` and spawn the QEMU emulator from
> +  the build directory.
> +
>  ``config-host.mak``
>    When configure has determined the characteristics of the build host it
>    will write the paths to various tools to this file, for use in
> ``Makefile``
> diff --git a/docs/devel/testing/functional.rst
> b/docs/devel/testing/functional.rst
> index fdeaebaadc..1978f96eba 100644
> --- a/docs/devel/testing/functional.rst
> +++ b/docs/devel/testing/functional.rst
> @@ -53,15 +53,14 @@ the following line will only run the tests for the
> x86_64 target:
>    make check-functional-x86_64
>
>  To run a single test file without the meson test runner, you can also
> -execute the file directly by specifying two environment variables first,
> -the PYTHONPATH that has to include the python folder and the
> tests/functional
> -folder of the source tree, and QEMU_TEST_QEMU_BINARY that has to point
> -to the QEMU binary that should be used for the test. The current working
> -directory should be your build folder. For example::
> -
> -  $ export PYTHONPATH=../python:../tests/functional
> -  $ export QEMU_TEST_QEMU_BINARY=$PWD/qemu-system-x86_64
> -  $ pyvenv/bin/python3 ../tests/functional/test_file.py
> +execute the file directly by specifying the name of the emulator target
> +binary as an env variable.
> +
> +Assuming the current working directory is the top level source checkout
> +and the build directory is './build'::
> +
> +  $ export QEMU_TEST_QEMU_BINARY=qemu-system-x86_64
> +  $ ./build/run tests/functional/x86_64/test_virtio_version.py
>
>  The test framework will automatically purge any scratch files created
> during
>  the tests. If needing to debug a failed test, it is possible to keep these
> diff --git a/meson.build b/meson.build
> index d9293294d8..8f2320d362 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -3507,6 +3507,17 @@ endif
>  config_host_h = configure_file(output: 'config-host.h', configuration:
> config_host_data)
>  genh += config_host_h
>
> +run_config = configuration_data(
> +    {'build_dir': meson.current_build_dir(),
> +     'src_dir': meson.current_source_dir(),
> +     'bin_dir': get_option('prefix') / get_option('bindir')},
> +)
> +
> +run = configure_file(input: 'run.in',
> +                     output: 'run',
> +                     configuration: run_config)
> +run_command('chmod', 'a+x', meson.current_build_dir() / 'run', check:
> true)
> +
>  hxtool = find_program('scripts/hxtool')
>  shaderinclude = find_program('scripts/shaderinclude.py')
>  qapi_gen = find_program('scripts/qapi-gen.py')
> diff --git a/run.in b/run.in
> new file mode 100644
> index 0000000000..124f0daed2
> --- /dev/null
> +++ b/run.in
> @@ -0,0 +1,15 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +
> +# Ensure that we find our local builds first
> +PATH=@build_dir@/qemu-bundle/@bin_dir@:$PATH
> +export PATH
> +
> +# Ensure that functional tests find their lib
> +PYTHONPATH=@src_dir@/tests/functional${PYTHONPATH:+:${PYTHONPATH}}
> +export PYTHONPATH
> +
> +# Ensure that everything uses the venv python & site packages
> +source @build_dir@/pyvenv/bin/activate
> +
> +exec $@
> --
> 2.51.1
>

Do we want to bootstrap the Python env here, too? I know you said you
didn't want to invoke Ninja, but we can always invoke mkvenv directly if
you wanted to.

Like if not file pyvenv/checktests.group, then:

pyvenv/bin/python3 python/scripts/mkvenv.py ensuregroup [--dir
python/wheels] [--online] checktests

(Typing from memory on my phone, consult mkvenv.py for precise syntax. The
mkvenv ensuregroup invocation as configured, with conditional online flag,
is available through config-host.mak, too.)

This would skip Ninja and would run bootstrapping when the timestamp file
is absent, but would otherwise not check if the env is outdated. Still
might be pretty convenient so you can get e.g. qmp-shell-wrap right out of
the gate, or run iotests, etc.

Until my series goes in, you could also just invoke NINJA=":" make
check-venv, too, and I can update the invocation in my patchset if you want.

Lemme know.

--js

>

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