gateway

Service for multiplexing many Discord websockets on top of any number of backends. Consists of 2 components: Gateway & State Cache

NOTE: This currently only supports Tatsu's specific use case. More backends will be written in the future as time permits.

A custom ETF parser was written from the ground up. During peak traffic, gateway uses ~4 cores for 720 shards.

State is stored in foundationdb and accessed via the State Cache (cmd/state).

Events are pushed to redis using RPUSH. The content is the d key of the event encoded as ETF.

Common Dependencies

1. Ensure you have Go 1.13 or higher.
2. Install foundationdb (both the server and clients package).
3. Install redis.

Setting up the Gateway

1. Add a variable in cmd/gateway/main.go named Token that contains your token.
2. Enable modules export GO111MODULE=on
3. Run go build in cmd/gateway
4. To run, do ./gateway in cmd/gateway

Redis Configuration

The gateway requires the MULTI_REDIS environment variable to be set. This allows you to configure one or more Redis instances with optional per-instance event filtering.

Format: {"redis_address": ["EVENT_TYPE1", "EVENT_TYPE2"], ...}

Examples:

Single Redis instance, no event filtering (all events sent):

export MULTI_REDIS='{"localhost:6379":[]}'

Single Redis instance with event filtering:

export MULTI_REDIS='{"localhost:6379":["MESSAGE_CREATE","MESSAGE_UPDATE","MESSAGE_DELETE"]}'

Multiple Redis instances with different event filters:

export MULTI_REDIS='{"redis1.example.com:6379":["MESSAGE_CREATE","MESSAGE_UPDATE"],"redis2.example.com:6379":["GUILD_CREATE","GUILD_UPDATE"]}'

Setting up the State

1. Run go build in cmd/state
2. To run, do ./state in cmd/state