Idea: remote buffer

[jszwedko]

This idea came from gitter: https://gitter.im/timberio-vector/community?at=5f39b2efba27767ee5f5aba0

Opening here for discussion as I imagine this could be quite complicated and I'm not sure if it fits into the vision of Vector or not.

A user brought up the idea of buffering events in a remote storage when a sink is down to be sent when it comes back up.

An alternative, I think, would be to propagate the backpressure to the sources, making them responsible for queuing up messages. I could see for some sources, like the HTTP source, that they may get better behavior allowing Vector to still ingest.

Apparently Matomo has a similar feature where it'll buffer to Redis (or MySQL): https://matomo.org/faq/how-to-update/faq_20844/

Related to the idea of "dead letter queues": #1772

Possibly related, Fluentd's storage plugin architecture: https://docs.fluentd.org/storage ; though I note that only "local" is currently supported.

[binarylogic]

Closing in favor of #5463