Inferring reasons for stopped transfer?

[marcovidonis]

I'm looking for a way to understand and report why a downloading torrent stops before it's complete. I wonder whether there is some info available on what is being exchanged between leecher, seeder and tracker and how I could tap into that (and perhaps surface this info to outside the package) to infer what's happening. For example: Have all seeders disappeared? Has the leecher lost connection to the tracker? Etc.

I've gone through PeerConn, but I haven't been able to find anything holding the state of the connection (perhaps I missed something). I did notice an expVar.Map variable called torrent that keeps a count of several events, but I'm not sure whether it could be useful for this purpose.

Do you have any suggestions on how I could go about this?

[anacrolix]

I usually have a HTTP handler writing the torrent status somewhere. It's textual but you can usually work out problems from that and the goroutine trace. Here's an example: https://github.com/anacrolix/confluence/blob/10e015cde1c83daa33fcbe78f70d9b6fc749700f/confluence/handlers.go#L64-L66. You'll be able to see what the piece state is of the connected peers, and the amount of redundancy for each piece. You'll probably find some pieces are missing from the swarm.

[marcovidonis]

Thanks! That might just be what I need, I'll look into that!

[anacrolix]

Question answered.