aquatic/README.md
Joakim Frostegård a208775104
Include documentation in printed config files (#41)
* Start work on printing toml config with comments

* WIP: toml_config: extract default values for fields

* WIP: toml_config: handle single-level nested structs

* WIP: toml_config: improve comment handling, std type trait impls

* WIP: toml_config: add Private trait, improve comment handling, clean up

* toml_config: fix default value bug; improve tests

* Use toml_config in all applicable crates; add toml_config enum support

* toml_config: improve comments

* toml_config_derive: support enum comments

* Improve config comments for udp, cli_helpers, common

* Improve config comments

* Add tests for Config struct TomlConfig implementations

* Improve Config comments

* Improve Config comments

* ws, http: add config comments for tls cert and private key lines

* small fixes to toml_config and toml_config_derive

* Run cargo fmt

* Fix typo in several config comments

* Update README

* Update README
2021-12-26 11:33:27 +01:00

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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] | Unix-like |
| aquatic_http | [BitTorrent over HTTP] with TLS ([rustls]) | Linux 5.8+ |
| aquatic_ws | [WebTorrent] over TLS ([rustls]) | Unix-like with [mio] (default) / Linux 5.8+ with [glommio] |
## Usage
### Prerequisites
- Install Rust with [rustup](https://rustup.rs/) (stable is recommended)
- Install cmake with your package manager (e.g., `apt-get install cmake`)
- Unless you're planning to only run the cross-platform mio based
implementations, make sure locked memory limits are sufficient.
You can do this by adding the following lines to `/etc/security/limits.conf`,
and then logging out and back in:
```
* hard memlock 512
* soft memlock 512
```
- Clone this git repository and enter it
### Compiling
Compile the implementations that you are interested in:
```sh
# Tell Rust to enable support for all CPU extensions present on current CPU
# except for those relating to AVX-512. This is necessary for aquatic_ws and
# recommended for the other implementations.
. ./scripts/env-native-cpu-without-avx-512
cargo build --release -p aquatic_udp
cargo build --release -p aquatic_http
cargo build --release -p aquatic_ws
cargo build --release -p aquatic_ws --features "with-glommio" --no-default-features
```
### 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. You will likely want to adjust `address`
(listening address) under the `network` section.
Note that both `aquatic_http` and `aquatic_ws` require configuring TLS
certificate and private key files. More details are available in the
respective configuration files.
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"
```
### Configuration values
Starting more `socket_workers` than `request_workers` is recommended. All
implementations are quite IO-bound and spend a lot of their time reading from
and writing to sockets. This is handled by the socket workers, which
also do parsing, serialisation and access control. They pass announce and
scrape requests to the request workers, which update internal tracker state
and pass back responses for sending.
#### Access control
Access control by info hash is supported for all protocols. The relevant part
of configuration is:
```toml
[access_list]
# Access list mode. Available modes are white, black and off.
mode = "off"
# Path to access list file consisting of newline-separated hex-encoded info hashes.
path = ""
```
The file is read on start and when the program receives `SIGUSR1`. If initial
parsing fails, the program exits. Later failures result in in emitting of
an error-level log message, while successful updates of the access list result
in emitting of an info-level log message.
## 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.
#### Performance
![UDP BitTorrent tracker throughput comparison](./documents/aquatic-udp-load-test-illustration-2021-11-28.png)
More details are available [here](./documents/aquatic-udp-load-test-2021-11-28.pdf).
#### Optimisation attempts that didn't work out
* Using glommio
* Using io-uring
* Using zerocopy + vectored sends for responses
* Using sendmmsg
### 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.
### aquatic_ws: WebTorrent tracker
Aims for compatibility with [WebTorrent](https://github.com/webtorrent)
clients, 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
## Load testing
There are load test binaries for all protocols. They use a CLI structure
similar to the trackers 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.
## 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 ;-)