public static void StartSubscriber(IWebHost host)
{
using (var scope = host.Services.CreateScope())
{
var provider = scope.ServiceProvider;
var subscriptionOptions = provider.GetService <IOptions <SubscriberOptions> >();
Microsoft.Extensions.Logging.ILogger <Program> logger = provider.GetService <Microsoft.Extensions.Logging.ILogger <Program> >();
var readSourceName = subscriptionOptions.Value.TopicName;
if (string.IsNullOrWhiteSpace(readSourceName))
{
throw new Exception("Event store subcriber cannot be started.");
}
var repository = provider.GetService <IReadModelRepository <ReadPointer> >();
var readPointer = repository.GetAll()
.FirstOrDefault(x => x.SourceName == readSourceName);
if (readPointer == null)
{
readPointer = new ReadPointer
{
SourceName = readSourceName,
Position = -1,
CreatedOn = DateTime.Now,
LastModifiedOn = DateTime.Now,
PublicId = Guid.NewGuid()
};
Task.Run(() =>
{
try
{
repository.AddAsync(readPointer);
}
catch (Exception e)
{
logger.LogError(e, e.Message);
throw;
}
}).Wait();
}
var eventSubscriber = provider.GetService <IEventStoreSubscriber>();
if (eventSubscriber.IsStarted)
{
return;
}
var position = readPointer.Position < 0 ? null : readPointer.Position;
eventSubscriber.Start(position);
}
}
public ValuesEventConsumer(IOptions <SubscriberOptions> options,
IMongoClient mongoClient,
ILogger <ValuesEventConsumer> logger,
IReadModelRepository <ValueRecord> valueRecordsRepository,
IReadModelRepository <ReadPointer> readPointerRepository,
IEventStoreConnection eventStoreConnection) : base(options, eventStoreConnection)
{
_mongoClient = mongoClient;
_logger = logger;
_valueRecordsRepository = valueRecordsRepository;
_readPointerRepository = readPointerRepository;
// there must be at least one record!!!
_readPointer = _readPointerRepository.GetAll()
.First(x => x.SourceName == options.Value.TopicName);
}
