aquatic/README.md

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# aquatic
[![CargoBuildAndTest](https://github.com/greatest-ape/aquatic/actions/workflows/cargo-build-and-test.yml/badge.svg)](https://github.com/greatest-ape/aquatic/actions/workflows/cargo-build-and-test.yml) [![Test HTTP, UDP and WSS file transfer](https://github.com/greatest-ape/aquatic/actions/workflows/test-transfer.yml/badge.svg)](https://github.com/greatest-ape/aquatic/actions/workflows/test-transfer.yml)
Blazingly fast, multi-threaded BitTorrent tracker written in Rust, consisting
of sub-implementations for different protocols:
[BitTorrent over UDP]: https://libtorrent.org/udp_tracker_protocol.html
[BitTorrent over HTTP]: https://wiki.theory.org/index.php/BitTorrentSpecification#Tracker_HTTP.2FHTTPS_Protocol
[WebTorrent]: https://github.com/webtorrent
[rustls]: https://github.com/rustls/rustls
[native-tls]: https://github.com/sfackler/rust-native-tls
[mio]: https://github.com/tokio-rs/mio
[glommio]: https://github.com/DataDog/glommio
| Name | Protocol | OS requirements |
|--------------|--------------------------------------------|-----------------------------------------------------------------|
| aquatic_udp | [BitTorrent over UDP] | Cross-platform with [mio] (default) / Linux 5.8+ with [glommio] |
| aquatic_http | [BitTorrent over HTTP] with TLS ([rustls]) | Linux 5.8+ |
| aquatic_ws | [WebTorrent] with TLS (rustls) | Linux 5.8+ |
## Usage
### Prerequisites
- Install Rust with [rustup](https://rustup.rs/) (stable is recommended)
- Install cmake with your package manager (e.g., `apt-get install cmake`)
- Clone this git repository and enter it
### Compiling
Compile the implementations that you are interested in:
```sh
cargo build --release -p aquatic_udp
cargo build --release -p aquatic_udp --features "with-glommio" --no-default-features
cargo build --release -p aquatic_http
cargo build --release -p aquatic_ws
```
### Running
Begin by generating configuration files. They differ between protocols.
```sh
./target/release/aquatic_udp -p > "aquatic-udp-config.toml"
./target/release/aquatic_http -p > "aquatic-http-config.toml"
./target/release/aquatic_ws -p > "aquatic-ws-config.toml"
```
Make adjustments to the files. The values you will most likely want to adjust
are `socket_workers` (number of threads reading from and writing to sockets)
and `address` under the `network` section (listening address). This goes for
all three protocols.
`aquatic_http` requires configuring a TLS certificate file and a private key file
to run. More information is available futher down in this document.
Once done, run the tracker:
```sh
./target/release/aquatic_udp -c "aquatic-udp-config.toml"
./target/release/aquatic_http -c "aquatic-http-config.toml"
./target/release/aquatic_ws -c "aquatic-ws-config.toml"
```
More documentation of configuration file values might be available under
`src/lib/config.rs` in crates `aquatic_udp`, `aquatic_http`, `aquatic_ws`.
#### General settings
Access control by info hash is supported for all protocols. The relevant part
of configuration is:
```toml
[access_list]
mode = 'off' # Change to 'black' (blacklist) or 'white' (whitelist)
path = '' # Path to text file with newline-delimited hex-encoded info hashes
```
## Details on implementations
### aquatic_udp: UDP BitTorrent tracker
Aims to implements the
[UDP BitTorrent protocol](https://libtorrent.org/udp_tracker_protocol.html),
except that it:
* Doesn't care about IP addresses sent in announce requests. The packet
source IP is always used.
* Doesn't track of the number of torrent downloads (0 is always sent).
Supports IPv4 and IPv6 (BitTorrent UDP protocol doesn't support IPv6 very well,
however.)
For optimal performance, enable setting of core affinities in configuration.
#### Benchmarks
[opentracker]: http://erdgeist.org/arts/software/opentracker/
Server responses per second, best result in bold:
| workers | aquatic | [opentracker] |
|---------|-----------|---------------|
| 1 | n/a | __232k__ |
| 2 | __309k__ | 293k |
| 3 | __597k__ | 397k |
| 4 | __603k__ | 481k |
| 6 | __757k__ | 587k |
| 8 | __850k__ | 431k |
| 10 | __826k__ | 165k |
| 16 | __785k__ | 139k |
Please refer to `documents/aquatic-udp-load-test-2021-08-19.pdf` for more details.
#### Alternative implementation using io_uring
[io_uring]: https://en.wikipedia.org/wiki/Io_uring
[glommio]: https://github.com/DataDog/glommio
There is an alternative implementation that utilizes [io_uring] by running on
[glommio]. It only runs on Linux and requires a recent kernel (version 5.8 or later).
In some cases, it performs even better than the cross-platform implementation.
### aquatic_http: HTTP BitTorrent tracker
[HTTP BitTorrent protocol]: https://wiki.theory.org/index.php/BitTorrentSpecification#Tracker_HTTP.2FHTTPS_Protocol
Aims for compatibility with the [HTTP BitTorrent protocol], with some exceptions:
* Only runs over TLS
* Doesn't track of the number of torrent downloads (0 is always sent)
* Doesn't allow full scrapes, i.e. of all registered info hashes
`aquatic_http` has not been tested as much as `aquatic_udp` but likely works
fine.
#### TLS
A TLS certificate file (DER-encoded X.509) and a corresponding private key file
(DER-encoded ASN.1 in either PKCS#8 or PKCS#1 format) are required. Set their
paths in the configuration file, e.g.:
```toml
[network]
address = '0.0.0.0:3000'
tls_certificate_path = './cert.crt'
tls_private_key_path = './key.pk8'
```
### aquatic_ws: WebTorrent tracker
Aims for compatibility with [WebTorrent](https://github.com/webtorrent)
clients, with some exceptions:
* Only runs over TLS (wss protocol)
* Doesn't track of the number of torrent downloads (0 is always sent).
* Doesn't allow full scrapes, i.e. of all registered info hashes
#### TLS
Please see `aquatic_http` TLS section above.
#### Benchmarks
[wt-tracker]: https://github.com/Novage/wt-tracker
[bittorrent-tracker]: https://github.com/webtorrent/bittorrent-tracker
The following benchmark is not very realistic, as it simulates a small number
of clients, each sending a large number of requests. Nonetheless, I think that
it gives a useful indication of relative performance.
Server responses per second, best result in bold:
| workers | aquatic | [wt-tracker] | [bittorrent-tracker] |
|---------|------------|--------------|----------------------|
| 1 | n/a | __117k__ | 45k |
| 2 | __225k__ | n/a | n/a |
| 4 | __627k__ | n/a | n/a |
| 6 | __831k__* | n/a | n/a |
| 8 | __1209k__* | n/a | n/a |
| 10 | __1455k__* | n/a | n/a |
| 12 | __1650k__* | n/a | n/a |
| 14 | __1804k__* | n/a | n/a |
| 16 | __1789k__* | n/a | n/a |
\* Using a VPS with 32 vCPUs. The other measurements were made using a 16 vCPU VPS.
Please refer to `documents/aquatic-ws-load-test-2021-08-18.pdf` for more details.
__Note__: these benchmarks were made with the previous mio-based
implementation.
## Load testing
There are load test binaries for all protocols. They use a CLI structure
similar to `aquatic` and support generation and loading of configuration files.
To run, first start the tracker that you want to test. Then run the
corresponding load test binary:
```sh
./scripts/run-load-test-udp.sh
./scripts/run-load-test-http.sh
./scripts/run-load-test-ws.sh
```
To fairly compare HTTP performance to opentracker, set keepalive to false in
`aquatic_http` settings.
## Architectural overview
One or more socket workers open sockets, read and parse requests from peers and
send them through channels to request workers. The request workers go through
the requests, update shared internal tracker state as appropriate and generate
responses that are sent back to the socket workers. The responses are then
serialized and sent back to the peers.
This design means little waiting for locks on internal state occurs,
while network work can be efficiently distributed over multiple threads,
making use of SO_REUSEPORT setting.
## Copyright and license
Copyright (c) 2020-2021 Joakim Frostegård
Distributed under Apache 2.0 license (details in `LICENSE` file.)
## Trivia
The tracker is called aquatic because it thrives under a torrent of bits ;-)