public static TriggerMessageContext create
(BrokeredMessage brokeredMessage
, DataModelDbContext serviceDataModel)
{
if (brokeredMessage == null)
{
throw new ArgumentNullException(nameof(brokeredMessage));
}
if (serviceDataModel == null)
{
throw new ArgumentNullException(nameof(serviceDataModel));
}
var serviceContext
= new ServiceContext(
serviceDataModel: serviceDataModel
, serviceCommandFactory: new IngressGatewayCommandFactory()
, dataIngressTopic: new DataIngressTopic()
);
var message
= new Message(
requestId: Guid.Parse(brokeredMessage.CorrelationId)
, messageId: Guid.Parse(brokeredMessage.MessageId)
, message: brokeredMessage.GetBody <string>()
, messageType: brokeredMessage.ContentType
);
var messageContext
= new MessageContext(
serviceContext: serviceContext
, message: message
);
return
(new TriggerMessageContext(Guid.NewGuid(), messageContext));
}
public ServiceContext
(DataModelDbContext serviceDataModel
, ServiceCommandFactory serviceCommandFactory
, IIngressQueue dataIngressTopic)
{
if (serviceDataModel == null)
{
throw new ArgumentNullException(nameof(serviceDataModel));
}
if (serviceCommandFactory == null)
{
throw new ArgumentNullException(nameof(serviceCommandFactory));
}
if (dataIngressTopic == null)
{
throw new ArgumentNullException(nameof(dataIngressTopic));
}
ServiceDataModel = serviceDataModel;
ServiceCommandFactory = serviceCommandFactory;
DataIngressTopic = dataIngressTopic;
}
private void publishUnpublishedOutcomes()
{
Trace.TraceInformation($"{Name} - started publishing unpublished messages");
var serviceDataModel
= new DataModelDbContext();
try {
var serviceContext
= new ServiceContext(
serviceDataModel: serviceDataModel
, serviceCommandFactory: new IngressGatewayCommandFactory()
, dataIngressTopic: new DataIngressTopic()
);
foreach (var message in serviceDataModel.GetUnpublishedMessages())
{
Trace.TraceInformation($"{Name} - [{message.MessageId}] Publishing unpublished messages");
var outcomeContext
= new MessageContext(serviceContext, message);
publishOutcome(outcomeContext);
Trace.TraceInformation($"{Name} - [{message.MessageId}] Published unpublished messages");
}
} catch (Exception e) {
Trace.TraceError($"{Name} - Message : {e.Message}, Stack trace : {e.StackTrace}");
throw;
} finally {
serviceDataModel.Dispose();
}
Trace.TraceInformation($"{Name} - completed publishing unpublished messages");
}
private void handleMessage
(BrokeredMessage message)
{
if (message == null)
{
throw new ArgumentNullException(nameof(message));
}
Trace.TraceInformation($"{Name} - [{message.MessageId}] Received message");
var serviceDataModel
= new DataModelDbContext();
try {
var messageContext
= IngressGatewayTriggerMessageContextFactory
.create(message, serviceDataModel);
// There may be stale messages in the queue if we had a dirty shutdown
// as such we check each message first to see if it has been processed.
//
// The way the service is written if we have processed a message there
// will always be a message entry with the same id.
if (!messageContext
.MessageContext
.ServiceContext
.ServiceDataModel
.HasMessage(messageContext.MessageContext.Message.MessageId))
{
Trace.TraceInformation($"{Name} - [{message.MessageId}] Processing message");
// Process message performs any state changes and then
// writes the state changes, the message, and message
// outcome in one transaction.
//
// Publish outcome post the message outcome to the
// dataIngress topic and then set the message to published.
//
// This along with publishing unpublished messages when
// starting the service and the above check to see if
// the message has previously been published should
// ensure consistency so long as the message bus technology
// can detect duplicate messages which Service bus can.
// It is needed becasue we have two separate components
// ( the database and the Azure Service bus ) and you can
// never tell when the service may fail.
messageContext
.fmap(processMessage)
.fmap(publishOutcome)
;
}
Trace.TraceInformation($"{Name} - [{message.MessageId}] Completed message");
} catch (Exception e) {
Trace.TraceError($"{Name} - [{message.MessageId}] Error - Message: {e.Message}, Stack trace: {e.StackTrace}");
message.Abandon();
throw;
} finally {
serviceDataModel.Dispose();
}
}