/// <summary>
/// Executes child nodes of the current node.
/// </summary>
/// <param name="context">Current ExecutionContext.</param>
/// <returns>NodeResultStatus representing the current node result.</returns>
protected sealed override async Task <NodeResultStatus> PerformExecuteAsync(IExecutionContext <TSource> context)
{
if (ChildNode == null)
{
Logger.LogWarning("Child node of TransitionNode doesn't exist, node will be skipped.");
return(NodeResultStatus.NotRun);
}
Logger.LogDebug("Creating the TransitionNode destination subject.");
TDestination destSubject = await TransitionSourceAsync(context).ConfigureAwait(false);
var destContext = new ExecutionContext <TDestination>(destSubject, context.GlobalOptions);
Logger.LogDebug("Preparing to execute TransitionNode child.");
NodeResult destResult = await ChildNode.ExecuteAsync(destContext).ConfigureAwait(false);
var exceptions = destResult.GetFailExceptions().ToList();
if (exceptions.Count > 0)
{
Logger.LogInformation("TransitionNode child returned {0} exceptions.", exceptions.Count);
context.ParentResult.Exception = exceptions.Count == 1 ? exceptions[0] : new AggregateException(exceptions);
}
Logger.LogDebug("Creating the TransitionNode destination result.");
var resultSubject = await TransitionResultAsync(context, destResult).ConfigureAwait(false);
if (!context.Subject.Equals(resultSubject))
{
Logger.LogDebug("Source subject has changed, calling ChangeSubject.");
context.ChangeSubject(resultSubject);
}
return(destResult.Status);
}
/// <summary>
/// Used to kick off execution of a node with a default execution context for all subjects using Async WhenAll semantics internally .
/// </summary>
/// <param name="subjects">Subject to be moved through the node.</param>
/// <param name="options">Execution options to apply to running this enumerable of subjects.</param>
/// <returns>An aggregated NodeResult.</returns>
public async Task <NodeResult> ExecuteManyAsync(IEnumerable <T> subjects, ExecutionOptions options = null)
{
Guard.AgainstNullArgument("subjects", subjects);
var nodeTimer = new NodeTimer();
try
{
nodeTimer.LogStart(LogWriter, this, "ExecuteManyAsync");
_processManyMode = true;
Result = new NodeResult(default(T), Id, FlowId);
var subjectList = subjects.ToList();
if (subjectList.Count == 0)
{
return(Result);
}
if (options == null)
{
options = new ExecutionOptions();
}
LogWriter.Debug("Running all subjects asynchronously.");
Task aggregateTask = null;
try
{
var resultsQueue = new ConcurrentQueue <NodeResult>();
aggregateTask = subjectList.ForEachAsync(options.DegreeOfParallelism,
async x => resultsQueue.Enqueue(await ExecuteAsync(new ExecutionContext <T>(x, options))));
await aggregateTask;
Result.AddChildResults(resultsQueue);
}
catch
{
if (options.ThrowOnError)
{
if (aggregateTask != null && aggregateTask.Exception != null)
{
throw aggregateTask.Exception;
}
throw;
}
}
ProcessExecuteManyResults(options);
return(Result);
}
finally
{
_processManyMode = false;
nodeTimer.LogStop(LogWriter, this, "ExecuteAsync");
}
}
/// <summary>
/// Used to kick off execution of a node with a default execution context for all subjects in a serial manner.
/// </summary>
/// <param name="subjects">Subject to be moved through the node.</param>
/// <param name="options">Execution options to apply to running this enumerable of subjects.</param>
/// <returns>An aggregated NodeResult.</returns>
public async Task <NodeResult> ExecuteManySeriallyAsync(IEnumerable <T> subjects, ExecutionOptions options = null)
{
Guard.AgainstNullArgument("subjects", subjects);
var nodeTimer = new NodeTimer();
try
{
nodeTimer.LogStart(LogWriter, this, "ExecuteManySeriallyAsync");
_processManyMode = true;
var subjectList = subjects.ToList();
Result = new NodeResult(default(T), Id, FlowId);
if (subjectList.Count == 0)
{
return(Result);
}
if (options == null)
{
options = new ExecutionOptions();
}
foreach (var subject in subjectList)
{
try
{
LogWriter.Debug("Running all subjects asynchronously in a serial manner.");
NodeResult result = await ExecuteAsync(new ExecutionContext <T>(subject, options)).ConfigureAwait(false);
Result.AddChildResult(result);
}
catch (Exception)
{
if (options.ThrowOnError)
{
throw;
}
if (!options.ContinueOnFailure)
{
break;
}
}
}
ProcessExecuteManyResults(options);
return(Result);
}
finally
{
_processManyMode = false;
nodeTimer.LogStop(LogWriter, this, "ExecuteAsync");
}
}
/// <summary>
/// Creates a new execution context.
/// </summary>
/// <param name="subject">Subject of the current flow.</param>
/// <param name="globalOptions">Global options of the current flow.</param>
/// <param name="rootResult">Root result if one has already been established.</param>
public ExecutionContext(T subject, ExecutionOptions globalOptions = null, NodeResult rootResult = null)
{
State = new DynamicDictionary();
Subject = subject;
GlobalOptions = globalOptions ?? new ExecutionOptions();
if (rootResult != null)
{
ParentResult = rootResult;
}
}
/// <summary>
/// Prepares the execution context before the current node is run.
/// </summary>
/// <param name="context">Source context for preparation.</param>
/// <param name="result">The result reference to add to the current context.</param>
/// <returns>The execution context to be used in node execution.</returns>
protected sealed override IExecutionContext <T> PrepareExecutionContext(IExecutionContext <T> context,
NodeResult result)
{
Logger.LogDebug("Preparing execution context.");
var resultContext = new ExecutionContext <T>(context, result);
context.AddResult(result);
return(resultContext);
}
/// <summary>
/// Adds a result to the execution context.
/// </summary>
/// <param name="result">The result to add</param>
public void AddResult(NodeResult result)
{
if (ParentResult == null)
{
ParentResult = result;
}
else if (ParentResult != result)
{
ParentResult.AddChildResult(result);
}
}
/// <summary>
/// Creates a child context based on the parent context. Used for nesting multi-nodes inside of other nodes.
/// </summary>
/// <param name="parentContext">Parent of this context.</param>
/// <param name="parentResult">Parent result to set on the new context, if any.</param>
internal ExecutionContext(IExecutionContext <T> parentContext, NodeResult parentResult = null)
{
Guard.AgainstNullArgument("parentContext", parentContext);
Guard.AgainstNullArgumentProperty("parentContext", "Subject", parentContext.Subject);
Guard.AgainstNullArgumentProperty("parentContext", "GlobalOptions", parentContext.GlobalOptions);
Subject = parentContext.Subject;
State = parentContext.State;
GlobalOptions = parentContext.GlobalOptions;
ParentResult = parentResult;
CancelProcessing = parentContext.CancelProcessing;
}
/// <summary>
/// Executes child nodes of the current node.
/// </summary>
/// <param name="context">Current ExecutionContext.</param>
/// <returns>NodeResultStatus representing the current node result.</returns>
protected override async Task <NodeResultStatus> ExecuteChildrenAsync(IExecutionContext <T> context)
{
NodeResult result = null;
Logger.LogDebug("Running first matching child node.");
foreach (var childNode in Children)
{
result = await childNode.ExecuteAsync(context).ConfigureAwait(false);
if (result.Status != NodeResultStatus.NotRun || context.CancelProcessing)
{
break;
}
}
if (result != null)
{
return(result.Status);
}
return(NodeResultStatus.NotRun);
}
/// <summary>
/// Adds a child result to the current result.
/// </summary>
/// <param name="result">Result to add to child results.</param>
internal void AddChildResult(NodeResult result)
{
_childResults.Enqueue(result);
}
/// <summary>
/// Transitions the source based on the child result to prepare for return to the source flow.
/// </summary>
/// <param name="sourceContext">Context including the source subject.</param>
/// <param name="result">The result of the destination node.</param>
/// <returns>The transitioned subject.</returns>
protected async override sealed Task <TSource> TransitionResultAsync(IExecutionContext <TSource> sourceContext, NodeResult result)
{
if (TransitionResultFuncAsync != null)
{
LogWriter.Debug("TransitionResultFuncAsync exists, using this function.");
return(await TransitionResultFuncAsync(sourceContext, result).ConfigureAwait(false));
}
LogWriter.Debug("TransitionResultFuncAsync doesn't exist, returning original subject.");
return(sourceContext.Subject);
}
/// <summary>
/// Transitions the source based on the child result to prepare for.
/// </summary>
/// <param name="sourceContext">Context including the source subject.</param>
/// <param name="result">The result of the destination node.</param>
/// <returns>The transitioned subject.</returns>
protected virtual Task <TSource> TransitionResultAsync(IExecutionContext <TSource> sourceContext, NodeResult result)
{
return(Task.FromResult(sourceContext.Subject));
}
/// <summary>
/// Prepares the execution context before the current node is run.
/// </summary>
/// <param name="context">Source context for preparation.</param>
/// <param name="result">The result reference to add to the current context.</param>
/// <returns>The execution context to be used in node execution.</returns>
protected virtual IExecutionContext <T> PrepareExecutionContext(IExecutionContext <T> context, NodeResult result)
{
LogWriter.Debug("Preparing the execution context for execution.");
context.AddResult(result);
return(context);
}
/// <summary>
/// Used to kick off execution of a node with a specified execution context.
/// </summary>
/// <param name="sourceContext">ExecutionContext that includes a subject to be moved through the node.</param>
/// <returns>A NodeResult</returns>
public async Task <NodeResult> ExecuteAsync(IExecutionContext <T> sourceContext)
{
Guard.AgainstNullArgument("context", sourceContext);
Guard.AgainstNullArgumentProperty("context", "Subject", sourceContext.Subject);
var nodeTimer = new NodeTimer();
try
{
nodeTimer.LogStart(LogWriter, this, "ExecuteAsync");
if (Status != NodeRunStatus.NotRun)
{
LogWriter.Debug("Status does not equal 'NotRun', resetting the node before execution");
Reset();
}
var subject = sourceContext.Subject;
var result = new NodeResult(subject, Id, FlowId);
if (!_processManyMode)
{
Result = result;
}
IExecutionContext <T> context = PrepareExecutionContext(sourceContext, result);
OnBeforeExecute(context);
if (!context.CancelProcessing)
{
var effectiveOptions = GetEffectiveOptions(context.GlobalOptions);
if (!await ShouldExecuteInternalAsync(context).ConfigureAwait(false))
{
LogWriter.Info("ShouldExecute returned false, skipping execution");
return(result);
}
Status = NodeRunStatus.Running;
LogWriter.Debug("Executing the node");
try
{
result.Status = await PerformExecuteAsync(context).ConfigureAwait(false);
//Reset the subject in case it was changed.
result.Subject = context.Subject;
Status = NodeRunStatus.Completed;
LogWriter.Info("Node completed execution, status is {0}", result.Status);
}
catch (Exception ex)
{
LogWriter.Error("Node erred during execution, status is Failed", ex);
Status = NodeRunStatus.Faulted;
result.Subject = context.Subject;
result.Status = NodeResultStatus.Failed;
result.Exception = ex;
if (effectiveOptions.ThrowOnError)
{
throw;
}
}
OnAfterExecute(context);
}
sourceContext.CancelProcessing = context.CancelProcessing;
return(result);
}
finally
{
nodeTimer.LogStop(LogWriter, this, "ExecuteAsync");
}
}
