public async Task <IMessage> Add(string endpointId, IMessage message, uint timeToLiveSecs)
{
Preconditions.CheckNotNull(message, nameof(message));
if (!this.endpointSequentialStores.TryGetValue(Preconditions.CheckNonWhiteSpace(endpointId, nameof(endpointId)), out ISequentialStore <MessageRef> sequentialStore))
{
throw new InvalidOperationException($"SequentialStore for endpoint {nameof(endpointId)} not found");
}
if (!message.SystemProperties.TryGetValue(SystemProperties.EdgeMessageId, out string edgeMessageId))
{
throw new InvalidOperationException("Message does not contain required system property EdgeMessageId");
}
TimeSpan timeToLive = timeToLiveSecs == 0 ? this.timeToLive : TimeSpan.FromSeconds(timeToLiveSecs);
// First put the message in the entity store and then put it in the sequentialStore. This is because the pump can go fast enough that it
// reads the message from the sequential store and tries to find the message in the entity store before the message has been added to the
// entity store.
// Note - if we fail to add the message to the sequential store (for some reason), then we will end up not cleaning up the message in the
// entity store. But that should be rare enough that it might be okay. Also it is better than not being able to forward the message.
// Alternative is to add retry logic to the pump, but that is more complicated, and could affect performance.
// TODO - Need to support transactions for these operations. The underlying storage layers support it.
using (MetricsV0.MessageStoreLatency(endpointId))
{
await this.messageEntityStore.PutOrUpdate(
edgeMessageId,
new MessageWrapper(message),
(m) =>
{
m.RefCount++;
return(m);
});
}
try
{
using (MetricsV0.SequentialStoreLatency(endpointId))
{
long offset = await sequentialStore.Append(new MessageRef(edgeMessageId, timeToLive));
Events.MessageAdded(offset, edgeMessageId, endpointId);
return(new MessageWithOffset(message, offset));
}
}
catch (Exception)
{
// If adding the message to the SequentialStore throws, then remove the message from the EntityStore as well, so that there is no leak.
await this.messageEntityStore.Remove(edgeMessageId);
throw;
}
}
