Crate descartes_core 

Core discrete event simulation engine.

This crate provides the fundamental building blocks for discrete event simulation: time management, event scheduling, task execution, and component-based architecture.

Architecture Overview

The simulation is built around two main types:

• Simulation: The main entry point that owns the scheduler and components. Use this to run simulations, add components, and access simulation state.

• SchedulerHandle: A cloneable handle for scheduling events during simulation. Pass this to Tower service layers and other components that need to schedule events without direct access to the simulation.

Basic Usage

use descartes_core::{Simulation, SimTime, Executor};
use std::time::Duration;

// Create a simulation
let mut simulation = Simulation::default();

// Get a scheduler handle for Tower layers or other components
let scheduler = simulation.scheduler_handle();

// Schedule events, add components, run simulation
simulation.execute(Executor::unbound());

Scheduling Events

For simple scheduling from within the simulation:

simulation.schedule(SimTime::from_millis(100), component_key, MyEvent::Tick);

For Tower layers or components that need a cloneable handle:

let scheduler = simulation.scheduler_handle();
scheduler.schedule(SimTime::from_millis(100), component_key, MyEvent::Tick);

Time Model

All timing uses SimTime, which represents simulation time (not wall-clock time). This ensures deterministic, reproducible behavior across simulation runs.

Re-exports

pub use error::EventError;

pub use error::SimError;

pub use execute::Execute;

pub use execute::Executor;

pub use logging::component_span;

pub use logging::event_span;

pub use logging::init_detailed_simulation_logging;

pub use logging::init_simulation_logging;

pub use logging::init_simulation_logging_with_level;

pub use logging::simulation_span;

pub use logging::task_span;

pub use randomness::DrawSite;

pub use randomness::RandomProvider;

pub use request::AttemptStatus;

pub use request::Request;

pub use request::RequestAttempt;

pub use request::RequestAttemptId;

pub use request::RequestId;

pub use request::RequestStatus;

pub use request::Response;

pub use request::ResponseStatus;

pub use scheduler::current_time;

pub use scheduler::defer_wake;

pub use scheduler::defer_wake_after;

pub use scheduler::in_scheduler_context;

pub use scheduler::ClockRef;

pub use scheduler::EventEntry;

pub use scheduler::EventFrontierPolicy;

pub use scheduler::FifoFrontierPolicy;

pub use scheduler::FrontierEvent;

pub use scheduler::FrontierEventKind;

pub use scheduler::FrontierSignature;

pub use scheduler::Scheduler;

pub use scheduler::SchedulerHandle;

pub use scheduler::UniformRandomFrontierPolicy;

pub use task::ClosureTask;

pub use task::PeriodicTask;

pub use task::RetryTask;

pub use task::Task;

pub use task::TaskHandle;

pub use task::TaskId;

pub use task::TimeoutTask;

pub use time::SimTime;

pub use types::EventId;

pub use waker::create_des_waker;

pub use formal::CertificateError;

pub use formal::LyapunovError;

pub use formal::VerificationError;

Modules

async_runtime

DES-based async runtime.

dists

Distribution traits and implementations for arrival patterns and service times

error

Error types for the simulation framework

execute

formal

Formal reasoning capabilities for simulation verification

ids

logging

Structured logging for discrete event simulation debugging

randomness

Randomness facade for deterministic simulation.

request

Request and response data models for distributed system simulation

scheduler

Event scheduling and time management for discrete event simulation.

task

Task system for short-lived operations in DES

time

Simulation time management

types

Core type definitions and newtypes for the simulation framework

waker

Unified DES waker utilities.

Macros

draw_site

Generate a DrawSite at the macro expansion site.

sim_debug

sim_error

sim_info

sim_log_with_time

Helper for logging with simulation time context

sim_trace

Macros for convenient logging with simulation context

sim_warn

Structs

Components

Container holding type-erased components.

Key

Simulation

Simulation struct that puts different parts of the simulation together.

SimulationConfig

Global configuration for a simulation.

Traits

Component

ProcessEventEntry