public DemandSubscription Run(Demand demand)
{
// 1. Persist subscription
var demandSubscription = this.SubscriptionRepository.CreateDemandSubscription(demand);
// 2. Construct the pipeline
var pipeline = new SubscriptionPipeline <DemandSubscription, MarketRequestorEvent>()
{
Subscription = demandSubscription
};
this.RequestorEventPipelines.Add(demandSubscription.Id, pipeline);
// 3. Resolve the Demand against existing Offer subscriptions and:
// - pull the matching ones immediately to pipeline
// - ???push the Demand into pipelines of matching Offers???
// this is questionable, as this would "duplicate" the message exchange -
// - Providers would receive a "market proposal" from matching, and immediately respond with a counter proposal,
// thus the Requestors would almost certainly receive a "market proposal" and a subsequent "direct proposal"
// from most Providers (as there are few Requestors and many willing Providers)
// - So it is tempting to 'break the symmetry' and not forward the Demand automatically to Provider subscription pipelines.
foreach (var offerSubscription in this.ProviderEventPipelines.Values)
{
var offer = offerSubscription.Subscription.Offer;
var matchingResult = this.MarketResolver.MatchDemandOffer(demand.Properties.Select(prop => prop.Key + ((prop.Value == null) ? "" : ("=" + prop.Value))).ToArray(), demand.Constraints,
offer.Properties.Select(prop => prop.Key + ((prop.Value == null) ? "" : ("=" + prop.Value))).ToArray(), offer.Constraints);
switch (matchingResult)
{
case GolemMarketResolver.ResultEnum.True:
// Persist OfferProposal with
var offerProposal = this.ProposalRepository.SaveOfferProposal(demandSubscription.Id, offerSubscription.Subscription.Id, offer); // no "previous proposal id" as we are mathcing the "on market" demands/offers
this.OfferSubscriptions.Add(offerProposal.Id, offerSubscription.Subscription.Id);
// Build Provider OfferProposal event and put in Requestor pipeline
var requestorEvent = new MarketRequestorEvent()
{
EventType = MarketRequestorEvent.MarketRequestorEventType.Proposal,
OfferProposal = offerProposal,
ProviderId = offer.NodeId
};
if (!pipeline.PipelineQueue.TryAdd(requestorEvent))
{
// TODO what do we do if unable to Add (eg. due to collection full)?
// Log warning?
// Should iteration be stopped now (to allow the Requestor to collect results?)
// What about other possible Offers that were skipped? they will not have a chance of being matched again...
}
break;
default:
break;
}
}
return(demandSubscription);
}
public void Subscribe(SubscriptionPipeline <TMessage> receiver)
{
async ValueTask Subscription(TMessage message)
{
var result = await receiver(message).ConfigureAwait(false);
if (result == false)
{
Pipe -= Subscription;
}
}
Pipe += Subscription;
}
