File_info_poller send_stream() problem

[kurotych]

Hello.
When I worked with the file_store library I faced a critical (as for me) issue in the file_info_poller module.
Currently, I don't use this part of the code but I think it is worth mentioning.

I had an error "Error streaming entry" due to reset connections by a peer (I kept it too long open) .

But I can't detect it because all I have "outside" is only the next() function.
So I can't distinguish if it is the end of the file or an error in a stream. In both cases, the loop finishes because next() returns None.

let mut rewards = file.into_stream(&mut tx).await?;
while let Some(reward) = rewards.next().await {
  ...
}

https://github.com/helium/oracles/blob/main/file_store/src/file_info_poller.rs#L175

[madninja]

@kurotych do you actually have an instance where streaming from a file causes an error that ends up in a None? The primary case here would be if you're trying to decode the wrong kind of proto from the file I guess.. or the filesystem has corruption which would be very rare

[kurotych]

Currently, I don't have any instances.

The error message was "Error streaming entry in the file of type..." so it is not a proto problem.
I believe the problem was caused by closing the connection from the AWS side (I kept it open long because of heavy computation).

I'm going to return to developing an appropriate module that can use this code next week and I'll try to prepare clear steps to reproduce.

[kurotych]

Releated: #715

[bbalser]

@kurotych I believe this issue is fixed with #715 , can you confirm?

[kurotych]

Hi @bbalser. I'm not sure.

What I see is a good improvement in file_info_poller. Now you parse proto files inside file_info_poller this significantly reduces the open connection time (to AWS) so reduces the chance of occurring error described above.

But, I still see an old part of the code in main branch that caused an issue and "hides" the connection error under coupling ok() and filter_map().
That means that the chance to parse half of the file (for example) before the connection was closed (reset by aws or due to connection reason) exists.

I believe parse_file must return an error if the connection was closed/reset because it means that the file wasn't fully downloaded.
Currently, it looks like in the connection trouble case it just finishes parsing the file, prints errors to logs, and returns with Ok() losing another part of the file.

Maybe I'm wrong but I don't have the appropriate tool and time to test it.

That's why I still prefer (or have to) to use the cut version of this file, without this function.

https://github.com/helium/oracles/blob/main/file_store/src/file_info_poller.rs#L262