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 Postgres and accessed via the State Cache (cmd/state). Pass the Postgres address with -psqlAddr (gateway) or -psql (state); it is required.

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 Postgres.
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