configure.py

#!/usr/bin/env python3
#
# This file is open source software, licensed to you under the terms
# of the Apache License, Version 2.0 (the "License").  See the NOTICE file
# distributed with this work for additional information regarding copyright
# ownership.  You may not use this file except in compliance with the License.
#
# You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.
#
import argparse
import os
import re
import seastar_cmake
from shutil import which
import subprocess
import sys
import tempfile

tempfile.tempdir = "./build/tmp"


def add_tristate(arg_parser, name, dest, help, default=None):
    arg_parser.add_argument('--enable-' + name, dest=dest, action='store_true', default=default,
                            help='Enable ' + help + ' [default]' if default else '')
    arg_parser.add_argument('--disable-' + name, dest=dest, action='store_false', default=None,
                            help='Disable ' + help)


def try_compile(compiler, source='', flags=[]):
    return try_compile_and_link(compiler, source, flags=flags + ['-c'])


def ensure_tmp_dir_exists():
    if not os.path.exists(tempfile.tempdir):
        os.makedirs(tempfile.tempdir)


def try_compile_and_link(compiler, source='', flags=[]):
    ensure_tmp_dir_exists()
    with tempfile.NamedTemporaryFile() as sfile:
        ofd, ofile = tempfile.mkstemp()
        os.close(ofd)
        try:
            sfile.file.write(bytes(source, 'utf-8'))
            sfile.file.flush()
            # We can't write to /dev/null, since in some cases (-ftest-coverage) gcc will create an auxiliary
            # output file based on the name of the output file, and "/dev/null.gcsa" is not a good name
            return subprocess.call([compiler, '-x', 'c++', '-o', ofile, sfile.name] + flags,
                                   stdout=subprocess.DEVNULL,
                                   stderr=subprocess.DEVNULL) == 0
        finally:
            if os.path.exists(ofile):
                os.unlink(ofile)


def standard_supported(standard, compiler='g++'):
    return try_compile(compiler=compiler, source='', flags=['-std=' + standard])


def find_compiler_cache(preference):
    """
    Find a compiler cache based on the preference.

    Args:
        preference: One of 'auto', 'sccache', 'ccache', 'none', or a path to a binary.

    Returns:
        Path to the compiler cache binary, or empty string if not found/disabled.
    """
    if preference == 'none':
        return ''

    if preference == 'auto':
        # Prefer sccache over ccache
        for cache in ['sccache', 'ccache']:
            path = which(cache)
            if path:
                return path
        return ''

    if preference in ('sccache', 'ccache'):
        path = which(preference)
        if path:
            return path
        print(f"Warning: {preference} not found on PATH, disabling compiler cache")
        return ''

    # Assume it's a path to a binary
    if os.path.isfile(preference) and os.access(preference, os.X_OK):
        return preference

    print(f"Warning: compiler cache '{preference}' not found or not executable, disabling compiler cache")
    return ''


def find_compiler(name):
    """
    Find a compiler by name, skipping ccache wrapper directories.

    This is useful when using sccache to avoid double-caching through ccache.

    Args:
        name: The compiler name (e.g., 'clang++', 'clang', 'gcc')

    Returns:
        Path to the compiler, skipping ccache directories, or None if not found.
    """
    ccache_dirs = {'/usr/lib/ccache', '/usr/lib64/ccache'}
    for path_dir in os.environ.get('PATH', '').split(os.pathsep):
        # Skip ccache wrapper directories
        if os.path.realpath(path_dir) in ccache_dirs or path_dir in ccache_dirs:
            continue
        candidate = os.path.join(path_dir, name)
        if os.path.isfile(candidate) and os.access(candidate, os.X_OK):
            return candidate
    return None


def resolve_compilers_for_compiler_cache(args, compiler_cache):
    """
    When using a compiler cache, resolve compiler paths to avoid ccache directories.

    This prevents double-caching when ccache symlinks are in PATH.

    Args:
        args: The argument namespace with cc and cxx attributes.
        compiler_cache: Path to the compiler cache binary, or empty string.
    """
    if not compiler_cache:
        return
    if not os.path.isabs(args.cxx):
        real_cxx = find_compiler(args.cxx)
        if real_cxx:
            args.cxx = real_cxx
    if not os.path.isabs(args.cc):
        real_cc = find_compiler(args.cc)
        if real_cc:
            args.cc = real_cc


arg_parser = argparse.ArgumentParser('Configure seastar')
arg_parser.add_argument('--mode', action='store', choices=seastar_cmake.SUPPORTED_MODES + ['all'], default='all')
arg_parser.add_argument('--build-root', action='store', default=seastar_cmake.DEFAULT_BUILD_ROOT, type=str,
                        help='The name of the build root build directoy: using a different name allows multiple '
                        'configurations to co-exist in the same repository')
arg_parser.add_argument('--cflags', action = 'store', dest='user_cflags', default='',
                        help='Extra flags for the C++ compiler')
arg_parser.add_argument('--ldflags', action='store', dest='user_ldflags', default='',
                        help='Extra flags for the linker')
arg_parser.add_argument('--optflags', action='store', dest='user_optflags', default='',
                        help='Extra optimization flags for the release mode')
arg_parser.add_argument('--api-level', action='store', dest='api_level', default='10',
                        help='Compatibility API level (10=latest)')
arg_parser.add_argument('--compiler', action='store', dest='cxx', default='g++',
                        help='C++ compiler path')
arg_parser.add_argument('--c-compiler', action='store', dest='cc', default='gcc',
                        help='C compiler path (for bundled libraries such as dpdk)')
arg_parser.add_argument('--compiler-cache', dest='compiler_cache', default='auto',
                        help="Use a compiler cache: 'auto' (prefer sccache over ccache), 'sccache', 'ccache', 'none' to disable, or a path to a compiler cache binary")
arg_parser.add_argument('--c++-standard', action='store', dest='cpp_standard', default='',
                        help='C++ standard to build with')
arg_parser.add_argument('--cook', action='append', dest='cook', default=[],
                        help='Supply this dependency locally for development via `cmake-cooking` (can be repeated)')
arg_parser.add_argument('--verbose', dest='verbose', action='store_true', help='Make configure output more verbose.')
arg_parser.add_argument('--scheduling-groups-count', action='store', dest='scheduling_groups_count', default='16',
                        help='Number of available scheduling groups in the reactor')

add_tristate(
    arg_parser,
    name='dpdk',
    dest='dpdk',
    help='DPDK support')
add_tristate(
    arg_parser,
    name='cxx-modules',
    dest='cxx_modules',
    help='build as C++20 module')
add_tristate(
    arg_parser,
    name='hwloc',
    dest='hwloc',
    help='hwloc support')
add_tristate(
    arg_parser,
    name='alloc-failure-injector',
    dest='alloc_failure_injection',
    help='allocation failure injection')
add_tristate(
    arg_parser,
    name='task-backtrace',
    dest='task_backtrace',
    help='Collect backtrace at deferring points')
add_tristate(
    arg_parser,
    name='unused-result-error',
    dest="unused_result_error",
    help='Make [[nodiscard]] violations an error')
add_tristate(
    arg_parser,
    name='debug-shared-ptr',
    dest="debug_shared_ptr",
    help='Debug shared_ptr')
add_tristate(
    arg_parser,
    name='io_uring',
    dest='io_uring',
    help='Support io_uring via liburing')
add_tristate(
    arg_parser,
    name='gnutls',
    dest='gnutls',
    help='the GnuTLS TLS/crypto backend')
add_tristate(
    arg_parser,
    name='openssl',
    dest='openssl',
    help='the OpenSSL TLS/crypto backend')
add_tristate(
    arg_parser,
    name='lttng',
    dest='lttng',
    help='LTTng-UST tracepoint support for IO tracing')
arg_parser.add_argument('--allocator-page-size', dest='alloc_page_size', type=int, help='override allocator page size')
arg_parser.add_argument('--without-tests', dest='exclude_tests', action='store_true', help='Do not build tests by default')
arg_parser.add_argument('--without-apps', dest='exclude_apps', action='store_true', help='Do not build applications by default')
arg_parser.add_argument('--without-demos', dest='exclude_demos', action='store_true', help='Do not build demonstrations by default')
arg_parser.add_argument('--split-dwarf', dest='split_dwarf', action='store_true', default=False,
                        help='use of split dwarf (https://gcc.gnu.org/wiki/DebugFission) to speed up linking')
arg_parser.add_argument('--compile-commands-json', dest='cc_json', action='store_true',
                        help='Generate a compile_commands.json file for integration with clangd and other tools.')
arg_parser.add_argument('--heap-profiling', dest='heap_profiling', action='store_true', default=False, help='Enable heap profiling')
arg_parser.add_argument('--dpdk-machine', default='native', help='Specify the target architecture')
add_tristate(arg_parser, name='deferred-action-require-noexcept', dest='deferred_action_require_noexcept', help='noexcept requirement for deferred actions', default=True)
arg_parser.add_argument('--prefix', dest='install_prefix', default='/usr/local', help='Root installation path of Seastar files')
args = arg_parser.parse_args()


def identify_best_standard(cpp_standards, compiler):
    """Returns the first C++ standard accepted by the compiler in the sequence,
    assuming the "best" standards appear first.

    If no standards are accepted, we fail configure.py. There is not point
    of letting the user attempt to build with a standard that is known not
    to be supported.
    """
    for std in cpp_standards:
        if standard_supported('c++{}'.format(std), compiler):
            return std
    raise Exception(f"{compiler} does not seem to support any of Seastar's preferred C++ standards - {cpp_standards}. Please upgrade your compiler.")


if not args.cpp_standard:
    cpp_standards = ['26', '23']
    args.cpp_standard = identify_best_standard(cpp_standards, compiler=args.cxx)

# Resolve compiler cache
compiler_cache = find_compiler_cache(args.compiler_cache)
resolve_compilers_for_compiler_cache(args, compiler_cache)


MODES = seastar_cmake.SUPPORTED_MODES if args.mode == 'all' else [args.mode]

# For convenience.
tr = seastar_cmake.translate_arg

MODE_TO_CMAKE_BUILD_TYPE = {'release': 'RelWithDebInfo', 'debug': 'Debug', 'dev': 'Dev', 'sanitize': 'Sanitize', 'fuzz': 'Fuzz'}


def get_valid_ingredients():
    """Extract valid ingredient names from cooking_recipe.cmake."""
    recipe_path = os.path.join(seastar_cmake.ROOT_PATH, 'cooking_recipe.cmake')
    with open(recipe_path, 'r') as f:
        content = f.read()
    # Match cooking_ingredient(name or cooking_ingredient (name
    matches = re.findall(r'cooking_ingredient\s*\(\s*([\w-]+)', content)
    return set(matches)


def configure_mode(mode):
    BUILD_PATH = seastar_cmake.build_path(mode, build_root=args.build_root)

    CFLAGS = seastar_cmake.convert_strings_to_cmake_list(
        args.user_cflags,
        args.user_optflags if seastar_cmake.is_release_mode(mode) else '')

    LDFLAGS = seastar_cmake.convert_strings_to_cmake_list(args.user_ldflags)

    TRANSLATED_ARGS = [
        '-DCMAKE_BUILD_TYPE={}'.format(MODE_TO_CMAKE_BUILD_TYPE[mode]),
        '-DCMAKE_CXX_COMPILER={}'.format(args.cxx),
        '-DCMAKE_CXX_STANDARD={}'.format(args.cpp_standard),
        '-DCMAKE_CXX_COMPILER_LAUNCHER={}'.format(compiler_cache),
        '-DCMAKE_INSTALL_PREFIX={}'.format(args.install_prefix),
        '-DCMAKE_EXPORT_COMPILE_COMMANDS={}'.format('yes' if args.cc_json else 'no'),
        '-DBUILD_SHARED_LIBS={}'.format('yes' if mode in ('debug', 'dev') else 'no'),
        '-DSeastar_API_LEVEL={}'.format(args.api_level),
        '-DSeastar_SCHEDULING_GROUPS_COUNT={}'.format(args.scheduling_groups_count),
        tr(args.exclude_tests, 'EXCLUDE_TESTS_FROM_ALL'),
        tr(args.exclude_apps, 'EXCLUDE_APPS_FROM_ALL'),
        tr(args.exclude_demos, 'EXCLUDE_DEMOS_FROM_ALL'),
        tr(CFLAGS, 'CXX_FLAGS'),
        tr(LDFLAGS, 'LD_FLAGS'),
        tr(args.cxx_modules, 'MODULE'),
        tr(args.dpdk, 'DPDK'),
        tr(args.dpdk_machine, 'DPDK_MACHINE'),
        tr(args.hwloc, 'HWLOC', value_when_none='yes'),
        tr(args.io_uring, 'IO_URING', value_when_none=None),
        tr(args.gnutls, 'GNUTLS', value_when_none=None),
        tr(args.openssl, 'OPENSSL', value_when_none=None),
        tr(args.lttng, 'LTTNG', value_when_none='yes'),
        tr(args.alloc_failure_injection, 'ALLOC_FAILURE_INJECTION', value_when_none='DEFAULT'),
        tr(args.task_backtrace, 'TASK_BACKTRACE'),
        tr(args.alloc_page_size, 'ALLOC_PAGE_SIZE'),
        tr(args.split_dwarf, 'SPLIT_DWARF'),
        tr(args.heap_profiling, 'HEAP_PROFILING'),
        tr(args.deferred_action_require_noexcept, 'DEFERRED_ACTION_REQUIRE_NOEXCEPT'),
        tr(args.unused_result_error, 'UNUSED_RESULT_ERROR'),
        tr(args.debug_shared_ptr, 'DEBUG_SHARED_PTR', value_when_none='default'),
    ]

    if not which('ninja-build') and which('ninja'):
        TRANSLATED_ARGS.append('-DCMAKE_MAKE_PROGRAM=ninja')

    ingredients_to_cook = set(args.cook)

    if ingredients_to_cook:
        valid_ingredients = get_valid_ingredients()
        invalid = ingredients_to_cook - valid_ingredients
        if invalid:
            print(f"error: unknown ingredient(s): {', '.join(sorted(invalid))}")
            print(f"valid ingredients: {', '.join(sorted(valid_ingredients))}")
            sys.exit(1)

    if args.dpdk:
        ingredients_to_cook.add('dpdk')

    # Generate a new build by pointing to the source directory.
    if ingredients_to_cook:
        # the C compiler is only used when building ingredients.
        TRANSLATED_ARGS.append(f'-DCMAKE_C_COMPILER={args.cc}')

        # We need to use cmake-cooking for some dependencies.
        inclusion_arguments = []

        for ingredient in ingredients_to_cook:
            inclusion_arguments.extend(['-i', ingredient])

        ARGS = seastar_cmake.COOKING_BASIC_ARGS + inclusion_arguments
        if args.user_cflags:
            ARGS += ['-s', f'CXXFLAGS={args.user_cflags}']
        if args.user_ldflags:
            ARGS += ['-s', f'LDFLAGS={args.user_ldflags}']
        ARGS += ['-d', BUILD_PATH, '--']
        dir = seastar_cmake.ROOT_PATH
    else:
        # When building without cooked dependencies, we can invoke cmake directly. We can't call
        # cooking.sh, because without any -i parameters, it will try to build
        # everything.
        root_relative_to_build = os.path.relpath(seastar_cmake.ROOT_PATH, BUILD_PATH)
        ARGS = ['cmake', '-G', 'Ninja', root_relative_to_build]
        dir = BUILD_PATH
    # filter out empty args, their values are actually "guess",
    # CMake should be able to figure it out.
    ARGS += filter(lambda arg: arg, TRANSLATED_ARGS)
    if args.verbose:
        print("Running CMake in '{}' ...".format(dir))
        print(" \\\n  ".join(ARGS))
    os.makedirs(BUILD_PATH, exist_ok=True)
    subprocess.check_call(ARGS, shell=False, cwd=dir)


for mode in MODES:
    configure_mode(mode)