New Feature: Rate limiting about torrent

[anacrolix]

There are no current plans. I believe it's quite straightforward. It can be done via a connection hook. All writing and reading on the wire are done via connection.rw. That's already a series of hooks that take care of protocol encryption, TCP vs. uTP, as well as deadlines. You could add a hook either before any handshaking occurs (client.{incoming,outgoing}Connection), or during the message exchange loop (client.connectionLoop) as you see fit. Rate limiting on downloads would result in the peer doing the appropriate things with the protocol. Rate limiting on upload is a little harder. Currently connection.writeOptimizer will help significantly applying backpressure from inability to write due to rate limiting back to the client. There's probably some improvements that could be done there, but it's not necessary to get the basics working.

I tried to link to areas of the code via https://sourcegraph.com/github.com/anacrolix/torrent but it didn't work very well.

[jpillora]

Passing a facade connection.rw sounds like a good idea. Could newConnection() become newConnection(nc net.Conn)? Could then move c.conn = nc and c.rw = nc inside the constructor.

Then before you call newConnection:

type ConnectionHook func(nc net.Conn) net.Conn

func (cl *client) SetDownloadHook(hook ConnectionHook) {
}
func (cl *client) SetUploadHook(hook ConnectionHook) {
}

//outgoing
if cl.hookUpload != nil {
  nc = cl.HookUpload(nc)
}
c := newConnection(nc)


//incoming
if cl.hookDownload != nil {
  nc = cl.hookDownload(nc)
}
c := newConnection(nc)

Or hooks could just be public, and you set them directly.

I can try my hand at a PR if needed

[anacrolix]

I believe newConnection did take a bunch of arguments previously to completely instantiate itself in one go. I removed a lot of assumptions from it (like that it had to be connected immediately) so as to allow manipulating a lot of its optional state, and installing hooks as required. If you see in receiveHandshakes and initiateHandshakes that connection fields are then further manipulated, I thought it best not to give people the false assumption that fields like rw and conn were necessarily only assigned to in newConnection.

I think since connections can exist before torrents are even added, that perhaps the hooks could come in via the client Config. I see no reason to allow modifying the hooks once a client is already created via NewClient. This will let us simplify our management of the hooks. A PR would be great. When/where to install the hooks is up to you. That is whether you want them before or after handshakes, above or below the encryption/BitTorrent protocol or directly on top of the transport.

I'm also not sure if it's necessary to separate the ReadWriter into separate parts (ie by having Upload/Download separate). I'm not sure what's gained/lost from this. At least presently it's rw io.ReadWriter, but the read/write parts are used separately. Whatever works best.

[jpillora]

Hey @anacrolix sorry, haven't had time to look into this for a while. I've started my torrent client and I've got a ways to go, though rate limiting still will be needed.

Check out the planned features https://github.com/jpillora/cloud-torrent and let me know if it's something you'd use or if you have any ideas - comment on the issues - we'll leave this issue just for rate limiting.

[anacrolix]

I have a similar private project. anacrolix/torrent is designed with supporting the features you require for that project in mind.

[jpillora]

Alrighty, well if you ever want to combine forces - let me know

[anacrolix]

@jpillora Note this was fixed in d4cbdc5 and 836bb34.

[jpillora]

Ah cool 👍

…

On Thu, 7 Nov 2019 at 8:12 am Matt Joiner ***@***.***> wrote: @jpillora <https://github.com/jpillora> Note this was fixed in d4cbdc5 <d4cbdc5> and 836bb34 <836bb34> . — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#11?email_source=notifications&email_token=AAE2X4654S7QBTOI2AT6RTDQSMXL7A5CNFSM4A7LCTLKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEDIAAIA#issuecomment-550502432>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAE2X475BPIL7PGH6DWKQVDQSMXL7ANCNFSM4A7LCTLA> .