+ * - In order for Python to free its variables, it must be terminated. + * - In order for Python to be terminated, the JVM must be terminated. + * - In order for the JVM to be terminated, all its non-daemon threads must be terminated. + * - Executors keep all its threads alive until it is freed/have no more references. + * - In order for the Executor to be freed/have no more references, it cannot have a reference in Python. + * - To not have a reference in Python means Python must free its variables, creating the Catch-22 + *
+ * Thus, if non-daemon threads are used, and a {@link ai.timefold.solver.core.api.solver.SolverManager} + * solves at least one problem (creating a keep-alive thread in its {@link java.util.concurrent.ThreadPoolExecutor}), + * Python cannot shut down gracefully and will become unresponsive when interrupted. + *
+ * This class uses {@link Executors#defaultThreadFactory()} to create a new thread, but sets the created + * thread to daemon mode so Python can shut down gracefully. + */ +public class DaemonThreadFactory implements ThreadFactory { + private static final ThreadFactory THREAD_FACTORY = Executors.defaultThreadFactory(); + + @Override + public Thread newThread(Runnable runnable) { + Thread out = THREAD_FACTORY.newThread(runnable); + out.setDaemon(true); + return out; + } +} diff --git a/timefold-solver-python-core/src/main/python/_solver_manager.py b/timefold-solver-python-core/src/main/python/_solver_manager.py index ecdb79e0..38eb0fcf 100644 --- a/timefold-solver-python-core/src/main/python/_solver_manager.py +++ b/timefold-solver-python-core/src/main/python/_solver_manager.py @@ -1,5 +1,5 @@ from ._problem_change import ProblemChange, ProblemChangeWrapper -from .config import SolverConfigOverride +from .config import SolverConfig, SolverConfigOverride, SolverManagerConfig from ._solver_factory import SolverFactory from ._future import wrap_future from ._timefold_java_interop import update_log_level @@ -342,14 +342,18 @@ def __init__(self, delegate: '_JavaSolverManager'): self._delegate = delegate @staticmethod - def create(solver_factory: 'SolverFactory[Solution_]') -> 'SolverManager[Solution_, ProblemId_]': + def create(solver_factory_or_config: 'SolverConfig | SolverFactory[Solution_]', + solver_manager_config: 'SolverManagerConfig' = None) -> 'SolverManager[Solution_, ProblemId_]': """ - Use a `SolverFactory` to build a `SolverManager`. + Use a `SolverConfig` or `SolverFactory` to build a `SolverManager`. Parameters ---------- - solver_factory : SolverFactory[Solution_] - The `SolverFactory` to build the `SolverManager` from. + solver_factory_or_config : SolverConfig | SolverFactory[Solution_] + The `SolverConfig` or `SolverFactory` to build the `SolverManager` from. + + solver_manager_config: SolverManagerConfig, optional + Additional settings that can be used to configure the `SolverManager`. Returns ------- @@ -357,7 +361,19 @@ def create(solver_factory: 'SolverFactory[Solution_]') -> 'SolverManager[Solutio A new `SolverManager` instance. """ from ai.timefold.solver.core.api.solver import SolverManager as JavaSolverManager - return SolverManager(JavaSolverManager.create(solver_factory._delegate)) # noqa + from ai.timefold.solver.python import DaemonThreadFactory + + if solver_manager_config is None: + solver_manager_config = SolverManagerConfig() + + java_solver_manager_config = solver_manager_config._to_java_solver_manager_config() # noqa + java_solver_manager_config.setThreadFactoryClass(DaemonThreadFactory.class_) + + if isinstance(solver_factory_or_config, SolverConfig): + solver_factory_or_config = SolverFactory.create(solver_factory_or_config) + + return SolverManager(JavaSolverManager.create(solver_factory_or_config._delegate, # noqa + java_solver_manager_config)) def solve(self, problem_id: ProblemId_, problem: Solution_, final_best_solution_listener: Callable[[Solution_], None] = None) -> SolverJob[Solution_, ProblemId_]: diff --git a/timefold-solver-python-core/src/main/python/config/_config.py b/timefold-solver-python-core/src/main/python/config/_config.py index d625fc18..a64f12d5 100644 --- a/timefold-solver-python-core/src/main/python/config/_config.py +++ b/timefold-solver-python-core/src/main/python/config/_config.py @@ -1,7 +1,7 @@ from ..score import ConstraintFactory, Constraint, IncrementalScoreCalculator from .._timefold_java_interop import is_enterprise_installed -from typing import Any, Optional, Callable, TypeVar, Generic, TYPE_CHECKING +from typing import Any, Optional, Callable, TypeVar, Generic, Literal, TYPE_CHECKING from dataclasses import dataclass, field from enum import Enum from pathlib import Path @@ -378,6 +378,29 @@ def _to_java_solver_config_override(self): return out +@dataclass(kw_only=True) +class SolverManagerConfig: + """ + Includes settings to configure a SolverManager. + + Attributes + ---------- + parallel_solver_count: int | 'AUTO', optional + If set to an integer, the number of parallel jobs that can be run + simultaneously. + If unset or set to 'AUTO', the number of parallel jobs is determined + based on the number of CPU cores available. + """ + parallel_solver_count: Optional[int | Literal['AUTO']] = field(default=None) + + def _to_java_solver_manager_config(self): + from ai.timefold.solver.core.config.solver import SolverManagerConfig as JavaSolverManagerConfig + out = JavaSolverManagerConfig() + if self.parallel_solver_count is not None: + out = out.withParallelSolverCount(str(self.parallel_solver_count)) + return out + + __all__ = ['Duration', 'EnvironmentMode', 'TerminationCompositionStyle', - 'RequiresEnterpriseError', 'MoveThreadCount', + 'RequiresEnterpriseError', 'MoveThreadCount', 'SolverManagerConfig', 'SolverConfig', 'SolverConfigOverride', 'ScoreDirectorFactoryConfig', 'TerminationConfig']