/// <summary>
/// Initializes a new instance of the <see cref="OperationScheduler"/> class.
/// </summary>
internal OperationScheduler(ControlledRuntime runtime, ISchedulingStrategy strategy,
ScheduleTrace trace, Configuration configuration)
{
this.Configuration = configuration;
this.Runtime = runtime;
this.Strategy = strategy;
this.OperationMap = new Dictionary <ulong, AsyncOperation>();
this.ScheduleTrace = trace;
this.SyncObject = new object();
this.CompletionSource = new TaskCompletionSource <bool>();
this.IsAttached = true;
this.BugFound = false;
this.HasFullyExploredSchedule = false;
}
/// <summary>
/// Constructs a reproducable trace.
/// </summary>
private void ConstructReproducableTrace(ControlledRuntime runtime)
{
StringBuilder stringBuilder = new StringBuilder();
if (this.Strategy.IsFair())
{
stringBuilder.Append("--fair-scheduling").Append(Environment.NewLine);
}
if (this.Configuration.IsLivenessCheckingEnabled)
{
stringBuilder.Append("--liveness-temperature-threshold:" +
this.Configuration.LivenessTemperatureThreshold).
Append(Environment.NewLine);
}
if (!string.IsNullOrEmpty(this.Configuration.TestMethodName))
{
stringBuilder.Append("--test-method:" +
this.Configuration.TestMethodName).
Append(Environment.NewLine);
}
for (int idx = 0; idx < runtime.Scheduler.ScheduleTrace.Count; idx++)
{
ScheduleStep step = runtime.Scheduler.ScheduleTrace[idx];
if (step.Type == ScheduleStepType.SchedulingChoice)
{
stringBuilder.Append($"({step.ScheduledOperationId})");
}
else if (step.BooleanChoice != null)
{
stringBuilder.Append(step.BooleanChoice.Value);
}
else
{
stringBuilder.Append(step.IntegerChoice.Value);
}
if (idx < runtime.Scheduler.ScheduleTrace.Count - 1)
{
stringBuilder.Append(Environment.NewLine);
}
}
this.ReproducableTrace = stringBuilder.ToString();
}
/// <summary>
/// Gathers the exploration strategy statistics from the specified runtimne.
/// </summary>
private void GatherTestingStatistics(ControlledRuntime runtime)
{
TestReport report = runtime.Scheduler.GetReport();
if (this.Configuration.ReportActivityCoverage)
{
report.CoverageInfo.CoverageGraph = this.Graph;
}
var coverageInfo = runtime.GetCoverageInfo();
report.CoverageInfo.Merge(coverageInfo);
this.TestReport.Merge(report);
// Also save the graph snapshot of the last iteration, if there is one.
this.Graph = coverageInfo.CoverageGraph;
}
/// <summary>
/// Take care of handling the <see cref="Configuration"/> settings for <see cref="Configuration.CustomActorRuntimeLogType"/>,
/// <see cref="Configuration.IsDgmlGraphEnabled"/>, and <see cref="Configuration.ReportActivityCoverage"/> by setting up the
/// LogWriters on the given <see cref="ControlledRuntime"/> object.
/// </summary>
private void InitializeCustomLogging(ControlledRuntime runtime)
{
if (!string.IsNullOrEmpty(this.Configuration.CustomActorRuntimeLogType))
{
var log = this.Activate <IActorRuntimeLog>(this.Configuration.CustomActorRuntimeLogType);
if (log != null)
{
runtime.RegisterLog(log);
}
}
if (this.Configuration.IsDgmlGraphEnabled || this.Configuration.ReportActivityCoverage)
{
// Registers an activity coverage graph builder.
runtime.RegisterLog(new ActorRuntimeLogGraphBuilder(false)
{
CollapseMachineInstances = this.Configuration.ReportActivityCoverage
});
}
if (this.Configuration.ReportActivityCoverage)
{
// Need this additional logger to get the event coverage report correct
runtime.RegisterLog(new ActorRuntimeLogEventCoverage());
}
if (this.Configuration.IsXmlLogEnabled)
{
this.XmlLog = new StringBuilder();
runtime.RegisterLog(new ActorRuntimeLogXmlFormatter(XmlWriter.Create(this.XmlLog,
new XmlWriterSettings()
{
Indent = true, IndentChars = " ", OmitXmlDeclaration = true
})));
}
}
/// <summary>
/// Runs the next testing iteration.
/// </summary>
private void RunNextIteration(int iteration)
{
if (!this.IsReplayModeEnabled && this.ShouldPrintIteration(iteration + 1))
{
this.Logger.WriteLine($"..... Iteration #{iteration + 1}");
// Flush when logging to console.
if (this.Logger is ConsoleLogger)
{
Console.Out.Flush();
}
}
// Runtime used to serialize and test the program in this iteration.
ControlledRuntime runtime = null;
// Logger used to intercept the program output if no custom logger
// is installed and if verbosity is turned off.
InMemoryLogger runtimeLogger = null;
// Gets a handle to the standard output and error streams.
var stdOut = Console.Out;
var stdErr = Console.Error;
try
{
// Creates a new instance of the controlled runtime.
runtime = new ControlledRuntime(this.Configuration, this.Strategy, this.RandomValueGenerator);
// If verbosity is turned off, then intercept the program log, and also redirect
// the standard output and error streams to a nul logger.
if (!this.Configuration.IsVerbose)
{
runtimeLogger = new InMemoryLogger();
runtime.SetLogger(runtimeLogger);
var writer = TextWriter.Null;
Console.SetOut(writer);
Console.SetError(writer);
}
this.InitializeCustomLogging(runtime);
// Runs the test and waits for it to terminate.
runtime.RunTest(this.TestMethodInfo.Method, this.TestMethodInfo.Name);
runtime.WaitAsync().Wait();
// Invokes the user-specified iteration disposal method.
this.TestMethodInfo.DisposeCurrentIteration();
// Invoke the per iteration callbacks, if any.
foreach (var callback in this.PerIterationCallbacks)
{
callback(iteration);
}
// Checks that no monitor is in a hot state at termination. Only
// checked if no safety property violations have been found.
if (!runtime.Scheduler.BugFound)
{
runtime.CheckNoMonitorInHotStateAtTermination();
}
if (runtime.Scheduler.BugFound)
{
this.ErrorReporter.WriteErrorLine(runtime.Scheduler.BugReport);
}
runtime.LogWriter.LogCompletion();
this.GatherTestingStatistics(runtime);
if (!this.IsReplayModeEnabled && this.TestReport.NumOfFoundBugs > 0)
{
if (runtimeLogger != null)
{
this.ReadableTrace = runtimeLogger.ToString();
this.ReadableTrace += this.TestReport.GetText(this.Configuration, "<StrategyLog>");
}
this.ConstructReproducableTrace(runtime);
}
}
finally
{
if (!this.Configuration.IsVerbose)
{
// Restores the standard output and error streams.
Console.SetOut(stdOut);
Console.SetError(stdErr);
}
if (!this.IsReplayModeEnabled && this.Configuration.PerformFullExploration && runtime.Scheduler.BugFound)
{
this.Logger.WriteLine($"..... Iteration #{iteration + 1} " +
$"triggered bug #{this.TestReport.NumOfFoundBugs} " +
$"[task-{this.Configuration.TestingProcessId}]");
}
// Cleans up the runtime before the next iteration starts.
runtimeLogger?.Dispose();
runtime?.Dispose();
}
}
/// <summary>
/// Initializes a new instance of the <see cref="TaskController"/> class.
/// </summary>
internal TaskController(ControlledRuntime runtime, OperationScheduler scheduler)
{
this.Runtime = runtime;
this.Scheduler = scheduler;
}
/// <summary>
/// Execute the (asynchronous) operation with the specified context.
/// </summary>
private TResult ExecuteOperation <TWork, TExecutor, TResult>(object state)
{
// Extract the expected operation context from the task state.
var context = state as AsyncOperationContext <TWork, TExecutor, TResult> ?? state as OperationContext <TWork, TResult>;
TaskOperation op = context.Operation;
CancellationToken ct = context.CancellationToken;
TResult result = default;
Exception exception = null;
// The operation execution logic uses two task completion sources: (1) an executor TCS and (2) a result TCS.
// We do this to model the execution of tasks in the .NET runtime. For example, the `Task.Factory.StartNew`
// method has different semantics from `Task.Run`, e.g. the returned task from `Task.Factory.StartNew(Func<T>)`
// completes at the start of an asynchronous operation, so someone cannot await on it for the completion of
// the operation. Instead, someone needs to first use `task.Unwrap()`, and then await on the unwrapped task.
// To model this, the executor TCS completes at the start of the operation, and contains in its `task.AsyncState`
// a reference to the result TCS. This approach allows us to implement `task.Unwrap` in a way that gives access
// to the result TCS, which someone can then await for the asynchronous completion of the operation.
try
{
// Update the current asynchronous control flow with the current runtime instance,
// allowing future retrieval in the same asynchronous call stack.
CoyoteRuntime.AssignAsyncControlFlowRuntime(this.Runtime);
// Notify the scheduler that the operation started. This will yield execution until
// the operation is ready to get scheduled.
this.Scheduler.StartOperation(op);
if (context is AsyncOperationContext <TWork, TExecutor, TResult> asyncContext)
{
// If the operation is asynchronous, then set the executor task completion source, which
// can be used by `UnwrapTask` to unwrap and return the task executing this operation.
this.SetTaskCompletionSource(asyncContext.ExecutorSource, asyncContext.Executor, null, ct);
}
if (context.Predecessor != null)
{
// If there is a predecessor task, then wait until the predecessor completes.
ct.ThrowIfCancellationRequested();
op.OnWaitTask(context.Predecessor);
}
// Check if the operation must be canceled before starting the work.
ct.ThrowIfCancellationRequested();
// Start executing the (asynchronous) work.
Task executor = null;
if (context.Work is Func <Task <TResult> > funcWithTaskResult)
{
executor = funcWithTaskResult();
}
else if (context.Work is Func <Task> funcWithTask)
{
executor = funcWithTask();
}
else if (context.Work is Func <CoyoteTasks.Task <TResult> > funcWithCoyoteTaskResult)
{
// TODO: temporary until we remove the custom task type.
executor = funcWithCoyoteTaskResult().UncontrolledTask;
}
else if (context.Work is Func <CoyoteTasks.Task> funcWithCoyoteTask)
{
// TODO: temporary until we remove the custom task type.
executor = funcWithCoyoteTask().UncontrolledTask;
}
else if (context.Work is Func <TResult> func)
{
result = func();
}
else
{
throw new NotSupportedException($"Unable to execute work with unsupported type {context.Work.GetType()}.");
}
if (executor != null)
{
// If the work is asynchronous, then wait until it completes.
this.OnWaitTask(op.Id, executor);
if (executor.IsFaulted)
{
// Propagate the failing exception by rethrowing it.
ExceptionDispatchInfo.Capture(executor.Exception).Throw();
}
else if (executor.IsCanceled)
{
if (op.Exception != null)
{
// An exception has been already captured, so propagate it.
ExceptionDispatchInfo.Capture(op.Exception).Throw();
}
else
{
// Wait the canceled executor (which is non-blocking as it has already completed)
// to throw the generated `OperationCanceledException`.
executor.Wait();
}
}
// Safely get the result without blocking as the work has completed.
result = executor is Task <TResult> resultTask ? resultTask.Result :
executor is TResult r ? r : default;
}
}
catch (Exception ex)
{
// Unwrap and cache the exception to propagate it.
exception = ControlledRuntime.UnwrapException(ex);
this.ReportThrownException(exception);
}
finally
{
IO.Debug.WriteLine("<ScheduleDebug> Completed operation '{0}' on task '{1}'.", op.Name, Task.CurrentId);
op.OnCompleted();
// Set the result task completion source to notify to the awaiters that the operation
// has been completed, and schedule the next enabled operation.
this.SetTaskCompletionSource(context.ResultSource, result, exception, default);
this.Scheduler.ScheduleNextOperation();
}
return(result);
}
/// <summary>
/// Execute the operation with the specified context.
/// </summary>
private void ExecuteOperation(object state)
{
// Extract the expected operation context from the task state.
var context = state as OperationContext <Action, object>;
TaskOperation op = context.Operation;
CancellationToken ct = context.CancellationToken;
Exception exception = null;
try
{
// Update the current asynchronous control flow with the current runtime instance,
// allowing future retrieval in the same asynchronous call stack.
CoyoteRuntime.AssignAsyncControlFlowRuntime(this.Runtime);
// Notify the scheduler that the operation started. This will yield execution until
// the operation is ready to get scheduled.
this.Scheduler.StartOperation(op);
if (context.Predecessor != null)
{
// If there is a predecessor task, then wait until the predecessor completes.
ct.ThrowIfCancellationRequested();
op.OnWaitTask(context.Predecessor);
}
if (context.Options.HasFlag(OperationExecutionOptions.YieldAtStart))
{
// Try yield execution to the next operation.
this.Scheduler.ScheduleNextOperation(true);
}
// Check if the operation must be canceled before starting the work.
ct.ThrowIfCancellationRequested();
// Start executing the work.
context.Work();
}
catch (Exception ex)
{
if (context.Options.HasFlag(OperationExecutionOptions.FailOnException))
{
this.Assert(false, "Unhandled exception. {0}", ex);
}
else
{
// Unwrap and cache the exception to propagate it.
exception = ControlledRuntime.UnwrapException(ex);
this.ReportThrownException(exception);
}
}
finally
{
IO.Debug.WriteLine("<ScheduleDebug> Completed operation '{0}' on task '{1}'.", op.Name, Task.CurrentId);
op.OnCompleted();
// Set the result task completion source to notify to the awaiters that the operation
// has been completed, and schedule the next enabled operation.
this.SetTaskCompletionSource(context.ResultSource, null, exception, default);
this.Scheduler.ScheduleNextOperation();
}
}
/// <summary>
/// Initializes a new instance of the <see cref="Resource"/> class.
/// </summary>
internal Resource()
{
this.Runtime = ControlledRuntime.Current;
this.AwaitingOperations = new HashSet <AsyncOperation>();
}
