twilight-gateway
twilight-gateway is an implementation of Discord's sharding gateway sessions.
This is responsible for receiving stateful events in real-time from Discord
and sending some stateful information.
It includes two primary types: the Shard and Cluster.
The Shard handles a single websocket connection and can manage up to 2500 guilds. If you manage a small bot in under about 2000 guilds, then this is what you use. See the Discord docs for more information on sharding.
The Cluster is an interface which manages the health of the shards it manages and proxies all of their events under one unified stream. This is useful to use if you have a large bot in over 1000 or 2000 guilds.
Examples
There are a few usage examples located in the root of the twilight
repository.
Features
Deserialization
twilight-gateway supports serde_json and simd-json for
deserializing and serializing events.
simd-json
The simd-json feature enables simd-json support to use simd features
of modern cpus to deserialize responses faster. It is not enabled by
default.
To use this feature you need to also add these lines to
<project root>/.cargo/config:
[]
= ["-C", "target-cpu=native"]
you can also use this environment variable RUSTFLAGS="-C target-cpu=native".
[]
= { = false, = ["rustls-native-roots", "simd-json"], = "0.2" }
TLS
twilight-gateway has features to enable tokio-tungstenite and
twilight-http's TLS features. These features are mutually exclusive.
rustls-native-roots is enabled by default.
native
The native feature enables tokio-tungstenite's native-tls
feature as well as twilight-http's native feature which is mostly
equivalent to using native-tls.
To enable native, do something like this in your Cargo.toml:
[]
= { = false, = ["native"], = "0.2" }
rustls-native-roots
The rustls-native-roots feature enables tokio-tungstenite's rustls-tls-native-roots feature and
twilight-http's rustls-native-roots feature, which use rustls as the TLS backend and rustls-native-certs
for root certificates.
This is enabled by default.
rustls-webpki-roots
The rustls-webpki-roots feature enables tokio-tungstenite's rustls-tls-webpki-roots feature and
twilight-http's rustls-webpki-roots feature, which use rustls as the TLS backend and webpki-roots
for root certificates.
This should be preferred over rustls-native-roots in Docker containers based on scratch.
zlib
zlib is enabled with the feature compression and one of the two zlib features
described below. Enabling any of the two features below will also enable
compression. compression is enabled by default.
There are 2 zlib features zlib-stock and zlib-simd for the library to work
one of them has to be enabled. If both are enabled it will use zlib-stock
zlib-stock enabled by default.
Enabling only zlib-simd will make the library use zlib-ng which is a modern
fork of zlib that is faster and more effective, but it needs cmake to compile.
Tracing
The tracing feature enables logging via the tracing crate.
This is enabled by default.
Metrics
The metrics feature provides metrics information via the metrics crate.
Some of the metrics logged are counters about received event counts and
their types and gauges about the capacity and efficiency of the inflater of
each shard.
This is disabled by default.