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Diffstat (limited to 'notes')
| -rw-r--r-- | notes/architecture.md | 56 | ||||
| -rw-r--r-- | notes/refs.md | 5 |
2 files changed, 61 insertions, 0 deletions
diff --git a/notes/architecture.md b/notes/architecture.md new file mode 100644 index 0000000..c9268c9 --- /dev/null +++ b/notes/architecture.md @@ -0,0 +1,56 @@ + +peers wrap connections with given clients (any transport type). each peer can +be talking about multiple feeds. state consists of which feeds, what the remote +has (feed, bitmap), and what chunks (feed, index) have been requested +("in-flight"). connection logic runs in threads, passes back and forth entire +messages in channels. + + ConnCommand + Send(DatNetMessage) + Terminate() + + ConnReply + Received(DatNetMessage) + Disconnected() + +A synchronizer event loop has local feeds (storage) and a bunch of peers. Extra +state includes mode configuration, feeds, "wanted" bitmap for each feed. +Callbacks for certain feed events allow for extension (eg, hyperdrive stuff). +Needs a timer event. + +Use chan and chan-signal for now (MPSC style)... tokio will be the future but +seems too unstable for now. mio is too low-level to use on it's own (eg, no +timers, no threads). Use two threads per peer: a "main" thread that does +connection setup, `chan_select`, and blocking writes, and a "reader" thread +that does blocking reads of entire messages (writing either into the main +thread or skipping straight to the output channel). Got this pattern from the +`rusty_torrent` package. Need to set some write timeout. Synchronizer handles +cleanup if peer isn't replying/heartbeating. + +Probably want a dedicated discovery thread/worker in the future, but for now +just do it synchronously and connect to up to N peers to start. + +Synchronize will select on: + + signal + graceful shutdown + unified_inbound + feed: depends on state; ignore for now + handshake: error, close connection? + have, info: update PeerState bitmap + unhave, info, want, unwant: ignore for now + request: depends on state; read from storage + cancel: ignore for now + data: write to storage, clear pending; send new request + tick + check peer states, kill if too slow + dump status to command line + +Synchronize needs state: +- "tried" peers, so we don't retry in a loop if they fail + +Synchronize options: +- whether or not to hook signals + +Where does drive logic live? Plugin, via callback, to Synchronize? Let's just +fold it in to synchronizer for now, as a mode flag. diff --git a/notes/refs.md b/notes/refs.md new file mode 100644 index 0000000..4995578 --- /dev/null +++ b/notes/refs.md @@ -0,0 +1,5 @@ + +Decent "Original" Bittorrent client description: + +https://github.com/mgp/coding-in-the-real-world/blob/master/manuscript/bittorrent-client-case-study.md + |