protected virtual async Task <PipelineContinuation> ExecuteContributor(ICommunicationContext context, ContributorCall call)
{
using (
PipelineLog.Operation(this,
"Executing contributor {0}.{1}".With(call.ContributorTypeName, call.Action.Method.Name)))
{
PipelineContinuation nextStep;
try
{
nextStep = await call.Action(context);
}
catch (Exception e)
{
context.Response.StatusCode = 500;
context.ServerErrors.Add(new Error
{
Title = "Fatal error",
Message = "An exception was thrown while processing a pipeline contributor",
Exception = e
});
nextStep = PipelineContinuation.Abort;
}
return(nextStep);
}
}
async Task RenderNow(ICommunicationContext context, PipelineStage stage)
{
PipelineLog.WriteDebug("Pipeline is in RenderNow mode.");
if (!stage.ResumeFrom <KnownStages.IOperationResultInvocation>())
{
if (stage.OwnerStage != null)
{
PipelineLog.WriteError("Trying to launch nested pipeline to render error failed.");
AttemptCatastrophicErrorNotification(context);
return;
}
using (
PipelineLog.Operation(this,
"Rendering contributor has already been executed. Calling a nested pipeline to render the error."))
{
var nestedPipeline = new PipelineStage(this, stage);
if (!nestedPipeline.ResumeFrom <KnownStages.IOperationResultInvocation>())
{
throw new InvalidOperationException("Could not find an IOperationResultInvocation in the new pipeline.");
}
await RunCallGraph(context, nestedPipeline);
}
}
}
public void Initialize()
{
if (IsInitialized)
{
return;
}
using (PipelineLog.Operation(this, "Initializing the pipeline."))
{
foreach (var item in _resolver.ResolveAll <IPipelineContributor>())
{
PipelineLog.WriteDebug("Initialized contributor {0}.", item.GetType().Name);
_contributors.Add(item);
}
_callGraph = GenerateCallGraph();
}
IsInitialized = true;
PipelineLog.WriteInfo("Pipeline has been successfully initialized.");
}
IEnumerable <ContributorCall> GenerateCallGraph()
{
var bootstrapper = _contributors.OfType <KnownStages.IBegin>().Single();
var tree = new DependencyTree <ContributorNotification>(
new ContributorNotification(bootstrapper, new Notification(this, null)));
foreach (var contrib in _contributors.Where(x => x != bootstrapper))
{
_notificationRegistrations.Clear();
using (PipelineLog.Operation(this, "Initializing contributor {0}.".With(contrib.GetType().Name)))
contrib.Initialize(this);
foreach (var reg in _notificationRegistrations.DefaultIfEmpty(new Notification(this, null)))
{
tree.CreateNode(new ContributorNotification(contrib, reg));
}
}
foreach (var notificationNode in tree.Nodes)
{
foreach (var parentNode in GetCompatibleTypes(tree,
notificationNode,
notificationNode.Value.Notification.AfterTypes))
{
parentNode.ChildNodes.Add(notificationNode);
}
foreach (var childNode in GetCompatibleTypes(tree,
notificationNode,
notificationNode.Value.Notification.BeforeTypes))
{
childNode.ParentNodes.Add(notificationNode);
}
}
var graph = tree.GetCallGraph().Select(x =>
new ContributorCall(x.Value.Contributor, x.Value.Notification.Target, x.Value.Notification.Description));
LogContributorCallChainCreated(graph);
return(graph);
}