/// <summary>
/// Runs the passed <see cref="IStepBody"/> in the given <see cref="IStepExecutionContext"/> while applying
/// any <see cref="IWorkflowStepMiddleware"/> registered in the system. Middleware will be run in the
/// order in which they were registered with DI with middleware declared earlier starting earlier and
/// completing later.
/// </summary>
/// <param name="context">The <see cref="IStepExecutionContext"/> in which to execute the step.</param>
/// <param name="body">The <see cref="IStepBody"/> body.</param>
/// <returns>A <see cref="Task{ExecutionResult}"/> to wait for the result of running the step</returns>
public async Task <ExecutionResult> ExecuteStep(
IStepExecutionContext context,
IStepBody body
)
{
// Build the middleware chain by reducing over all the middleware in reverse starting with step body
// and building step delegates that call out to the next delegate in the chain
Task <ExecutionResult> Step() => body.RunAsync(context);
var middlewareChain = _stepMiddleware
.Reverse()
.Aggregate(
(WorkflowStepDelegate)Step,
(previous, middleware) => () => middleware.HandleAsync(context, body, previous)
);
// Run the middleware chain
return(await middlewareChain());
}
public async Task <WorkflowExecutorResult> Execute(WorkflowInstance workflow, WorkflowOptions options)
{
var wfResult = new WorkflowExecutorResult();
var exePointers = new List <ExecutionPointer>(workflow.ExecutionPointers.Where(x => x.Active && (!x.SleepUntil.HasValue || x.SleepUntil < _datetimeProvider.Now.ToUniversalTime())));
var def = _registry.GetDefinition(workflow.WorkflowDefinitionId, workflow.Version);
if (def == null)
{
_logger.LogError("Workflow {0} version {1} is not registered", workflow.WorkflowDefinitionId, workflow.Version);
return(wfResult);
}
foreach (var pointer in exePointers)
{
var step = def.Steps.First(x => x.Id == pointer.StepId);
if (step != null)
{
try
{
switch (step.InitForExecution(wfResult, def, workflow, pointer))
{
case ExecutionPipelineDirective.Defer:
continue;
case ExecutionPipelineDirective.EndWorkflow:
workflow.Status = WorkflowStatus.Complete;
workflow.CompleteTime = _datetimeProvider.Now.ToUniversalTime();
continue;
}
if (!pointer.StartTime.HasValue)
{
pointer.StartTime = _datetimeProvider.Now.ToUniversalTime();
}
_logger.LogDebug("Starting step {0} on workflow {1}", step.Name, workflow.Id);
IStepBody body = step.ConstructBody(_serviceProvider);
if (body == null)
{
_logger.LogError("Unable to construct step body {0}", step.BodyType.ToString());
pointer.SleepUntil = _datetimeProvider.Now.ToUniversalTime().Add(options.ErrorRetryInterval);
wfResult.Errors.Add(new ExecutionError()
{
WorkflowId = workflow.Id,
ExecutionPointerId = pointer.Id,
ErrorTime = _datetimeProvider.Now.ToUniversalTime(),
Message = String.Format("Unable to construct step body {0}", step.BodyType.ToString())
});
continue;
}
IStepExecutionContext context = new StepExecutionContext()
{
Workflow = workflow,
Step = step,
PersistenceData = pointer.PersistenceData,
ExecutionPointer = pointer,
Item = pointer.ContextItem
};
ProcessInputs(workflow, step, body, context);
switch (step.BeforeExecute(wfResult, context, pointer, body))
{
case ExecutionPipelineDirective.Defer:
continue;
case ExecutionPipelineDirective.EndWorkflow:
workflow.Status = WorkflowStatus.Complete;
workflow.CompleteTime = _datetimeProvider.Now.ToUniversalTime();
continue;
}
var result = await body.RunAsync(context);
if (result.Proceed)
{
ProcessOutputs(workflow, step, body);
}
ProcessExecutionResult(workflow, def, pointer, step, result, wfResult);
step.AfterExecute(wfResult, context, result, pointer);
}
catch (Exception ex)
{
pointer.RetryCount++;
_logger.LogError("Workflow {0} raised error on step {1} Message: {2}", workflow.Id, pointer.StepId, ex.Message);
wfResult.Errors.Add(new ExecutionError()
{
WorkflowId = workflow.Id,
ExecutionPointerId = pointer.Id,
ErrorTime = _datetimeProvider.Now.ToUniversalTime(),
Message = ex.Message
});
switch (step.ErrorBehavior ?? def.DefaultErrorBehavior)
{
case WorkflowErrorHandling.Retry:
pointer.SleepUntil = _datetimeProvider.Now.ToUniversalTime().Add(step.RetryInterval ?? def.DefaultErrorRetryInterval ?? options.ErrorRetryInterval);
break;
case WorkflowErrorHandling.Suspend:
workflow.Status = WorkflowStatus.Suspended;
break;
case WorkflowErrorHandling.Terminate:
workflow.Status = WorkflowStatus.Terminated;
break;
}
Host.ReportStepError(workflow, step, ex);
}
}
else
{
_logger.LogError("Unable to find step {0} in workflow definition", pointer.StepId);
pointer.SleepUntil = _datetimeProvider.Now.ToUniversalTime().Add(options.ErrorRetryInterval);
wfResult.Errors.Add(new ExecutionError()
{
WorkflowId = workflow.Id,
ExecutionPointerId = pointer.Id,
ErrorTime = _datetimeProvider.Now.ToUniversalTime(),
Message = String.Format("Unable to find step {0} in workflow definition", pointer.StepId)
});
}
}
ProcessAfterExecutionIteration(workflow, def, wfResult);
DetermineNextExecutionTime(workflow);
return(wfResult);
}
private async Task ExecuteStep(WorkflowInstance workflow, WorkflowStep step, ExecutionPointer pointer, WorkflowExecutorResult wfResult, WorkflowDefinition def)
{
using (var scope = _scopeProvider.CreateScope())
{
_logger.LogDebug("Starting step {0} on workflow {1}", step.Name, workflow.Id);
IStepBody body = step.ConstructBody(scope.ServiceProvider);
if (body == null)
{
_logger.LogError("Unable to construct step body {0}", step.BodyType.ToString());
pointer.SleepUntil = _datetimeProvider.Now.ToUniversalTime().Add(_options.ErrorRetryInterval);
wfResult.Errors.Add(new ExecutionError()
{
WorkflowId = workflow.Id,
ExecutionPointerId = pointer.Id,
ErrorTime = _datetimeProvider.Now.ToUniversalTime(),
Message = $"Unable to construct step body {step.BodyType.ToString()}"
});
return;
}
IStepExecutionContext context = new StepExecutionContext()
{
Workflow = workflow,
Step = step,
PersistenceData = pointer.PersistenceData,
ExecutionPointer = pointer,
Item = pointer.ContextItem
};
foreach (var input in step.Inputs)
{
input.AssignInput(workflow.Data, body, context);
}
switch (step.BeforeExecute(wfResult, context, pointer, body))
{
case ExecutionPipelineDirective.Defer:
return;
case ExecutionPipelineDirective.EndWorkflow:
workflow.Status = WorkflowStatus.Complete;
workflow.CompleteTime = _datetimeProvider.Now.ToUniversalTime();
return;
}
var result = await body.RunAsync(context);
if (result.Proceed)
{
foreach (var output in step.Outputs)
{
output.AssignOutput(workflow.Data, body, context);
}
}
_executionResultProcessor.ProcessExecutionResult(workflow, def, pointer, step, result, wfResult);
step.AfterExecute(wfResult, context, result, pointer);
}
}
public async Task <WorkflowExecutorResult> Execute(WorkflowInstance workflow)
{
var wfResult = new WorkflowExecutorResult();
var exePointers = new List <ExecutionPointer>(workflow.ExecutionPointers.Where(x => x.Active && (!x.SleepUntil.HasValue || x.SleepUntil < _datetimeProvider.Now.ToUniversalTime())));
var def = _registry.GetDefinition(workflow.WorkflowDefinitionId, workflow.Version);
if (def == null)
{
_logger.LogError("Workflow {0} version {1} is not registered", workflow.WorkflowDefinitionId, workflow.Version);
return(wfResult);
}
foreach (var pointer in exePointers)
{
if (pointer.Status == PointerStatus.Cancelled)
{
continue;
}
var step = def.Steps.FindById(pointer.StepId);
if (step == null)
{
_logger.LogError("Unable to find step {0} in workflow definition", pointer.StepId);
pointer.SleepUntil = _datetimeProvider.Now.ToUniversalTime().Add(_options.ErrorRetryInterval);
wfResult.Errors.Add(new ExecutionError()
{
WorkflowId = workflow.Id,
ExecutionPointerId = pointer.Id,
ErrorTime = _datetimeProvider.Now.ToUniversalTime(),
Message = String.Format("Unable to find step {0} in workflow definition", pointer.StepId)
});
continue;
}
try
{
switch (step.InitForExecution(wfResult, def, workflow, pointer))
{
case ExecutionPipelineDirective.Defer:
continue;
case ExecutionPipelineDirective.EndWorkflow:
workflow.Status = WorkflowStatus.Complete;
workflow.CompleteTime = _datetimeProvider.Now.ToUniversalTime();
continue;
}
if (pointer.Status != PointerStatus.Running)
{
pointer.Status = PointerStatus.Running;
_publisher.PublishNotification(new StepStarted()
{
EventTimeUtc = _datetimeProvider.Now,
Reference = workflow.Reference,
ExecutionPointerId = pointer.Id,
StepId = step.Id,
WorkflowInstanceId = workflow.Id,
WorkflowDefinitionId = workflow.WorkflowDefinitionId,
Version = workflow.Version
});
}
if (!pointer.StartTime.HasValue)
{
pointer.StartTime = _datetimeProvider.Now.ToUniversalTime();
}
using (var scope = _scopeProvider.CreateScope())
{
_logger.LogDebug("Starting step {0} on workflow {1}", step.Name, workflow.Id);
IStepBody body = step.ConstructBody(scope.ServiceProvider);
if (body == null)
{
_logger.LogError("Unable to construct step body {0}", step.BodyType.ToString());
pointer.SleepUntil = _datetimeProvider.Now.ToUniversalTime().Add(_options.ErrorRetryInterval);
wfResult.Errors.Add(new ExecutionError()
{
WorkflowId = workflow.Id,
ExecutionPointerId = pointer.Id,
ErrorTime = _datetimeProvider.Now.ToUniversalTime(),
Message = String.Format("Unable to construct step body {0}", step.BodyType.ToString())
});
continue;
}
IStepExecutionContext context = new StepExecutionContext()
{
Workflow = workflow,
Step = step,
PersistenceData = pointer.PersistenceData,
ExecutionPointer = pointer,
Item = pointer.ContextItem
};
foreach (var input in step.Inputs)
{
input.AssignInput(workflow.Data, body, context);
}
switch (step.BeforeExecute(wfResult, context, pointer, body))
{
case ExecutionPipelineDirective.Defer:
continue;
case ExecutionPipelineDirective.EndWorkflow:
workflow.Status = WorkflowStatus.Complete;
workflow.CompleteTime = _datetimeProvider.Now.ToUniversalTime();
continue;
}
var result = await body.RunAsync(context);
if (result.Proceed)
{
foreach (var output in step.Outputs)
{
output.AssignOutput(workflow.Data, body, context);
}
}
_executionResultProcessor.ProcessExecutionResult(workflow, def, pointer, step, result, wfResult);
step.AfterExecute(wfResult, context, result, pointer);
}
}
catch (Exception ex)
{
_logger.LogError("Workflow {0} raised error on step {1} Message: {2}", workflow.Id, pointer.StepId, ex.Message);
wfResult.Errors.Add(new ExecutionError()
{
WorkflowId = workflow.Id,
ExecutionPointerId = pointer.Id,
ErrorTime = _datetimeProvider.Now.ToUniversalTime(),
Message = ex.Message
});
_executionResultProcessor.HandleStepException(workflow, def, pointer, step, ex);
Host.ReportStepError(workflow, step, ex);
}
_cancellationProcessor.ProcessCancellations(workflow, def, wfResult);
}
ProcessAfterExecutionIteration(workflow, def, wfResult);
DetermineNextExecutionTime(workflow);
return(wfResult);
}
private static Expression <Func <Task <ExecutionResult> > > RunMethodFor(IStepBody body) => () => body.RunAsync(A <IStepExecutionContext> ._);
