chore: reorganize rust crates

crates/gateway/Cargo.toml

@@ -0,0 +1,27 @@
+[package]
+name = "gateway"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+anyhow = { workspace = true }
+axum = { workspace = true }
+bytes = { workspace = true }
+chrono = { workspace = true }
+fred = { workspace = true }
+futures = { workspace = true }
+lazy_static = { workspace = true }
+libpk = { path = "../libpk" }
+metrics = { workspace = true }
+serde_json = { workspace = true }
+signal-hook = { workspace = true }
+tokio = { workspace = true }
+tracing = { workspace = true }
+
+twilight-gateway = { workspace = true }
+twilight-cache-inmemory = { workspace = true }
+twilight-util = { workspace = true }
+twilight-model = { workspace = true }
+twilight-http = { workspace = true }
+
+serde_variant = "0.1.3"

crates/gateway/src/cache_api.rs

@@ -0,0 +1,183 @@
+use axum::{
+    extract::{Path, State},
+    http::StatusCode,
+    response::{IntoResponse, Response},
+    routing::get,
+    Router,
+};
+use serde_json::{json, to_string};
+use tracing::{error, info};
+use twilight_model::id::Id;
+
+use crate::discord::{
+    cache::{dm_channel, DiscordCache, DM_PERMISSIONS},
+    gateway::cluster_config,
+};
+use std::sync::Arc;
+
+fn status_code(code: StatusCode, body: String) -> Response {
+    (code, body).into_response()
+}
+
+// this function is manually formatted for easier legibility of route_services
+#[rustfmt::skip]
+pub async fn run_server(cache: Arc<DiscordCache>) -> anyhow::Result<()> {
+    let app = Router::new()
+        .route(
+            "/guilds/:guild_id",
+            get(|State(cache): State<Arc<DiscordCache>>, Path(guild_id): Path<u64>| async move {
+                match cache.guild(Id::new(guild_id)) {
+                    Some(guild) => status_code(StatusCode::FOUND, to_string(&guild).unwrap()),
+                    None => status_code(StatusCode::NOT_FOUND, "".to_string()),
+                }
+            }),
+        )
+        .route(
+            "/guilds/:guild_id/members/@me",
+            get(|State(cache): State<Arc<DiscordCache>>, Path(guild_id): Path<u64>| async move {
+                match cache.0.member(Id::new(guild_id), libpk::config.discord.as_ref().expect("missing discord config").client_id) {
+                    Some(member) => status_code(StatusCode::FOUND, to_string(member.value()).unwrap()),
+                    None => status_code(StatusCode::NOT_FOUND, "".to_string()),
+                }
+            }),
+        )
+        .route(
+            "/guilds/:guild_id/permissions/@me",
+            get(|State(cache): State<Arc<DiscordCache>>, Path(guild_id): Path<u64>| async move {
+                match cache.guild_permissions(Id::new(guild_id), libpk::config.discord.as_ref().expect("missing discord config").client_id).await {
+                    Ok(val) => {
+                        status_code(StatusCode::FOUND, to_string(&val.bits()).unwrap())
+                    },
+                    Err(err) => {
+                        error!(?err, ?guild_id, "failed to get own guild member permissions");
+                        status_code(StatusCode::INTERNAL_SERVER_ERROR, "".to_string())
+                    },
+                }
+            }),
+        )
+        .route(
+            "/guilds/:guild_id/permissions/:user_id",
+            get(|State(cache): State<Arc<DiscordCache>>, Path((guild_id, user_id)): Path<(u64, u64)>| async move {
+                match cache.guild_permissions(Id::new(guild_id), Id::new(user_id)).await {
+                    Ok(val) => status_code(StatusCode::FOUND, to_string(&val.bits()).unwrap()),
+                    Err(err) => {
+                        error!(?err, ?guild_id, ?user_id, "failed to get guild member permissions");
+                        status_code(StatusCode::INTERNAL_SERVER_ERROR, "".to_string())
+                    },
+                }
+            }),
+        )
+
+        .route(
+            "/guilds/:guild_id/channels",
+            get(|State(cache): State<Arc<DiscordCache>>, Path(guild_id): Path<u64>| async move {
+                let channel_ids = match cache.0.guild_channels(Id::new(guild_id)) {
+                    Some(channels) => channels.to_owned(),
+                    None => return status_code(StatusCode::NOT_FOUND, "".to_string()),
+                };
+
+                let mut channels = Vec::new();
+                for id in channel_ids {
+                    match cache.0.channel(id) {
+                        Some(channel) => channels.push(channel.to_owned()),
+                        None => {
+                            tracing::error!(
+                                channel_id = id.get(),
+                                "referenced channel {} from guild {} not found in cache",
+                                id.get(), guild_id,
+                            );
+                            return status_code(StatusCode::INTERNAL_SERVER_ERROR, "".to_string());
+                        }
+                    }
+                }
+
+                status_code(StatusCode::FOUND, to_string(&channels).unwrap())
+            })
+        )
+        .route(
+            "/guilds/:guild_id/channels/:channel_id",
+            get(|State(cache): State<Arc<DiscordCache>>, Path((guild_id, channel_id)): Path<(u64, u64)>| async move {
+                if guild_id == 0 {
+                    return status_code(StatusCode::FOUND, to_string(&dm_channel(Id::new(channel_id))).unwrap());
+                }
+                match cache.0.channel(Id::new(channel_id)) {
+                    Some(channel) => status_code(StatusCode::FOUND, to_string(channel.value()).unwrap()),
+                    None => status_code(StatusCode::NOT_FOUND, "".to_string())
+                }
+            })
+        )
+        .route(
+            "/guilds/:guild_id/channels/:channel_id/permissions/@me",
+            get(|State(cache): State<Arc<DiscordCache>>, Path((guild_id, channel_id)): Path<(u64, u64)>| async move {
+                if guild_id == 0 {
+                    return status_code(StatusCode::FOUND, to_string(&*DM_PERMISSIONS).unwrap());
+                }
+                match cache.channel_permissions(Id::new(channel_id), libpk::config.discord.as_ref().expect("missing discord config").client_id).await {
+                    Ok(val) => status_code(StatusCode::FOUND, to_string(&val).unwrap()),
+                    Err(err) => {
+                        error!(?err, ?channel_id, ?guild_id, "failed to get own channelpermissions");
+                        status_code(StatusCode::INTERNAL_SERVER_ERROR, "".to_string())
+                    },
+                }
+            }),
+        )
+        .route(
+            "/guilds/:guild_id/channels/:channel_id/permissions/:user_id",
+            get(|| async { "todo" }),
+        )
+        .route(
+            "/guilds/:guild_id/channels/:channel_id/last_message",
+            get(|| async { status_code(StatusCode::NOT_IMPLEMENTED, "".to_string()) }),
+        )
+
+        .route(
+            "/guilds/:guild_id/roles",
+            get(|State(cache): State<Arc<DiscordCache>>, Path(guild_id): Path<u64>| async move {
+                let role_ids = match cache.0.guild_roles(Id::new(guild_id)) {
+                    Some(roles) => roles.to_owned(),
+                    None => return status_code(StatusCode::NOT_FOUND, "".to_string()),
+                };
+
+                let mut roles = Vec::new();
+                for id in role_ids {
+                    match cache.0.role(id) {
+                        Some(role) => roles.push(role.value().resource().to_owned()),
+                        None => {
+                            tracing::error!(
+                                role_id = id.get(),
+                                "referenced role {} from guild {} not found in cache",
+                                id.get(), guild_id,
+                            );
+                            return status_code(StatusCode::INTERNAL_SERVER_ERROR, "".to_string());
+                        }
+                    }
+                }
+
+                status_code(StatusCode::FOUND, to_string(&roles).unwrap())
+            })
+        )
+
+        .route("/stats", get(|State(cache): State<Arc<DiscordCache>>| async move {
+            let cluster = cluster_config();
+            let has_been_up = cache.2.read().await.len() as u32 == if cluster.total_shards > 16 {16} else {cluster.total_shards};
+            let stats = cache.0.stats();
+            let stats = json!({
+                "guild_count": stats.guilds(),
+                "channel_count": stats.channels(),
+                // just put this here until prom stats
+                "unavailable_guild_count": stats.unavailable_guilds(),
+                "up": has_been_up,
+            });
+            status_code(StatusCode::FOUND, to_string(&stats).unwrap())
+        }))
+
+        .layer(axum::middleware::from_fn(crate::logger::logger))
+        .with_state(cache);
+
+    let addr: &str = libpk::config.discord.as_ref().expect("missing discord config").cache_api_addr.as_ref();
+    let listener = tokio::net::TcpListener::bind(addr).await?;
+    info!("listening on {}", addr);
+    axum::serve(listener, app).await?;
+
+    Ok(())
+}

crates/gateway/src/discord/cache.rs

@@ -0,0 +1,368 @@
+use anyhow::format_err;
+use lazy_static::lazy_static;
+use std::sync::Arc;
+use tokio::sync::RwLock;
+use twilight_cache_inmemory::{
+    model::CachedMember,
+    permission::{MemberRoles, RootError},
+    traits::CacheableChannel,
+    InMemoryCache, ResourceType,
+};
+use twilight_model::{
+    channel::{Channel, ChannelType},
+    guild::{Guild, Member, Permissions},
+    id::{
+        marker::{ChannelMarker, GuildMarker, UserMarker},
+        Id,
+    },
+};
+use twilight_util::permission_calculator::PermissionCalculator;
+
+lazy_static! {
+    pub static ref DM_PERMISSIONS: Permissions = Permissions::VIEW_CHANNEL
+        | Permissions::SEND_MESSAGES
+        | Permissions::READ_MESSAGE_HISTORY
+        | Permissions::ADD_REACTIONS
+        | Permissions::ATTACH_FILES
+        | Permissions::EMBED_LINKS
+        | Permissions::USE_EXTERNAL_EMOJIS
+        | Permissions::CONNECT
+        | Permissions::SPEAK
+        | Permissions::USE_VAD;
+}
+
+pub fn dm_channel(id: Id<ChannelMarker>) -> Channel {
+    Channel {
+        id,
+        kind: ChannelType::Private,
+
+        application_id: None,
+        applied_tags: None,
+        available_tags: None,
+        bitrate: None,
+        default_auto_archive_duration: None,
+        default_forum_layout: None,
+        default_reaction_emoji: None,
+        default_sort_order: None,
+        default_thread_rate_limit_per_user: None,
+        flags: None,
+        guild_id: None,
+        icon: None,
+        invitable: None,
+        last_message_id: None,
+        last_pin_timestamp: None,
+        managed: None,
+        member: None,
+        member_count: None,
+        message_count: None,
+        name: None,
+        newly_created: None,
+        nsfw: None,
+        owner_id: None,
+        parent_id: None,
+        permission_overwrites: None,
+        position: None,
+        rate_limit_per_user: None,
+        recipients: None,
+        rtc_region: None,
+        thread_metadata: None,
+        topic: None,
+        user_limit: None,
+        video_quality_mode: None,
+    }
+}
+
+fn member_to_cached_member(item: Member, id: Id<UserMarker>) -> CachedMember {
+    CachedMember {
+        avatar: item.avatar,
+        communication_disabled_until: item.communication_disabled_until,
+        deaf: Some(item.deaf),
+        flags: item.flags,
+        joined_at: item.joined_at,
+        mute: Some(item.mute),
+        nick: item.nick,
+        premium_since: item.premium_since,
+        roles: item.roles,
+        pending: false,
+        user_id: id,
+    }
+}
+
+pub fn new() -> DiscordCache {
+    let mut client_builder = twilight_http::Client::builder().token(
+        libpk::config
+            .discord
+            .as_ref()
+            .expect("missing discord config")
+            .bot_token
+            .clone(),
+    );
+
+    if let Some(base_url) = libpk::config
+        .discord
+        .as_ref()
+        .expect("missing discord config")
+        .api_base_url
+        .clone()
+    {
+        client_builder = client_builder.proxy(base_url, true);
+    }
+
+    let client = Arc::new(client_builder.build());
+
+    let cache = Arc::new(
+        InMemoryCache::builder()
+            .resource_types(
+                ResourceType::GUILD
+                    | ResourceType::CHANNEL
+                    | ResourceType::ROLE
+                    | ResourceType::USER_CURRENT
+                    | ResourceType::MEMBER_CURRENT,
+            )
+            .message_cache_size(0)
+            .build(),
+    );
+
+    DiscordCache(cache, client, RwLock::new(Vec::new()))
+}
+
+pub struct DiscordCache(
+    pub Arc<InMemoryCache>,
+    pub Arc<twilight_http::Client>,
+    pub RwLock<Vec<u32>>,
+);
+
+impl DiscordCache {
+    pub async fn guild_permissions(
+        &self,
+        guild_id: Id<GuildMarker>,
+        user_id: Id<UserMarker>,
+    ) -> anyhow::Result<Permissions> {
+        if self
+            .0
+            .guild(guild_id)
+            .ok_or_else(|| format_err!("guild not found"))?
+            .owner_id()
+            == user_id
+        {
+            return Ok(Permissions::all());
+        }
+
+        let member = if user_id
+            == libpk::config
+                .discord
+                .as_ref()
+                .expect("missing discord config")
+                .client_id
+        {
+            self.0
+                .member(guild_id, user_id)
+                .ok_or(format_err!("self member not found"))?
+                .value()
+                .to_owned()
+        } else {
+            member_to_cached_member(
+                self.1
+                    .guild_member(guild_id, user_id)
+                    .await?
+                    .model()
+                    .await?,
+                user_id,
+            )
+        };
+
+        let MemberRoles { assigned, everyone } = self
+            .0
+            .permissions()
+            .member_roles(guild_id, &member)
+            .map_err(RootError::from_member_roles)?;
+        let calculator =
+            PermissionCalculator::new(guild_id, user_id, everyone, assigned.as_slice());
+
+        let permissions = calculator.root();
+
+        Ok(self
+            .0
+            .permissions()
+            .disable_member_communication(&member, permissions))
+    }
+
+    pub async fn channel_permissions(
+        &self,
+        channel_id: Id<ChannelMarker>,
+        user_id: Id<UserMarker>,
+    ) -> anyhow::Result<Permissions> {
+        let channel = self
+            .0
+            .channel(channel_id)
+            .ok_or(format_err!("channel not found"))?;
+
+        if channel.value().guild_id.is_none() {
+            return Ok(*DM_PERMISSIONS);
+        }
+
+        let guild_id = channel.value().guild_id.unwrap();
+
+        if self
+            .0
+            .guild(guild_id)
+            .ok_or_else(|| {
+                tracing::error!(
+                    channel_id = channel_id.get(),
+                    guild_id = guild_id.get(),
+                    "referenced guild from cached channel {channel_id} not found in cache"
+                );
+                format_err!("internal cache error")
+            })?
+            .owner_id()
+            == user_id
+        {
+            return Ok(Permissions::all());
+        }
+
+        let member = if user_id
+            == libpk::config
+                .discord
+                .as_ref()
+                .expect("missing discord config")
+                .client_id
+        {
+            self.0
+                .member(guild_id, user_id)
+                .ok_or_else(|| {
+                    tracing::error!(
+                        guild_id = guild_id.get(),
+                        "self member for cached guild {guild_id} not found in cache"
+                    );
+                    format_err!("internal cache error")
+                })?
+                .value()
+                .to_owned()
+        } else {
+            member_to_cached_member(
+                self.1
+                    .guild_member(guild_id, user_id)
+                    .await?
+                    .model()
+                    .await?,
+                user_id,
+            )
+        };
+
+        let MemberRoles { assigned, everyone } = self
+            .0
+            .permissions()
+            .member_roles(guild_id, &member)
+            .map_err(RootError::from_member_roles)?;
+
+        let overwrites = match channel.kind {
+            ChannelType::AnnouncementThread
+            | ChannelType::PrivateThread
+            | ChannelType::PublicThread => self.0.permissions().parent_overwrites(&channel)?,
+            _ => channel
+                .value()
+                .permission_overwrites()
+                .unwrap_or_default()
+                .to_vec(),
+        };
+
+        let calculator =
+            PermissionCalculator::new(guild_id, user_id, everyone, assigned.as_slice());
+
+        let permissions = calculator.in_channel(channel.kind(), overwrites.as_slice());
+
+        Ok(self
+            .0
+            .permissions()
+            .disable_member_communication(&member, permissions))
+    }
+
+    // from https://github.com/Gelbpunkt/gateway-proxy/blob/5bcb080a1fcb09f6fafecad7736819663a625d84/src/cache.rs
+    pub fn guild(&self, id: Id<GuildMarker>) -> Option<Guild> {
+        self.0.guild(id).map(|guild| {
+            let channels = self
+                .0
+                .guild_channels(id)
+                .map(|reference| {
+                    reference
+                        .iter()
+                        .filter_map(|channel_id| {
+                            let channel = self.0.channel(*channel_id)?;
+
+                            if channel.kind.is_thread() {
+                                None
+                            } else {
+                                Some(channel.value().clone())
+                            }
+                        })
+                        .collect()
+                })
+                .unwrap_or_default();
+
+            let roles = self
+                .0
+                .guild_roles(id)
+                .map(|reference| {
+                    reference
+                        .iter()
+                        .filter_map(|role_id| {
+                            Some(self.0.role(*role_id)?.value().resource().clone())
+                        })
+                        .collect()
+                })
+                .unwrap_or_default();
+
+            Guild {
+                afk_channel_id: guild.afk_channel_id(),
+                afk_timeout: guild.afk_timeout(),
+                application_id: guild.application_id(),
+                approximate_member_count: None, // Only present in with_counts HTTP endpoint
+                banner: guild.banner().map(ToOwned::to_owned),
+                approximate_presence_count: None, // Only present in with_counts HTTP endpoint
+                channels,
+                default_message_notifications: guild.default_message_notifications(),
+                description: guild.description().map(ToString::to_string),
+                discovery_splash: guild.discovery_splash().map(ToOwned::to_owned),
+                emojis: vec![],
+                explicit_content_filter: guild.explicit_content_filter(),
+                features: guild.features().cloned().collect(),
+                icon: guild.icon().map(ToOwned::to_owned),
+                id: guild.id(),
+                joined_at: guild.joined_at(),
+                large: guild.large(),
+                max_members: guild.max_members(),
+                max_presences: guild.max_presences(),
+                max_video_channel_users: guild.max_video_channel_users(),
+                member_count: guild.member_count(),
+                members: vec![],
+                mfa_level: guild.mfa_level(),
+                name: guild.name().to_string(),
+                nsfw_level: guild.nsfw_level(),
+                owner_id: guild.owner_id(),
+                owner: guild.owner(),
+                permissions: guild.permissions(),
+                public_updates_channel_id: guild.public_updates_channel_id(),
+                preferred_locale: guild.preferred_locale().to_string(),
+                premium_progress_bar_enabled: guild.premium_progress_bar_enabled(),
+                premium_subscription_count: guild.premium_subscription_count(),
+                premium_tier: guild.premium_tier(),
+                presences: vec![],
+                roles,
+                rules_channel_id: guild.rules_channel_id(),
+                safety_alerts_channel_id: guild.safety_alerts_channel_id(),
+                splash: guild.splash().map(ToOwned::to_owned),
+                stage_instances: vec![],
+                stickers: vec![],
+                system_channel_flags: guild.system_channel_flags(),
+                system_channel_id: guild.system_channel_id(),
+                threads: vec![],
+                unavailable: false,
+                vanity_url_code: guild.vanity_url_code().map(ToString::to_string),
+                verification_level: guild.verification_level(),
+                voice_states: vec![],
+                widget_channel_id: guild.widget_channel_id(),
+                widget_enabled: guild.widget_enabled(),
+            }
+        })
+    }
+}

crates/gateway/src/discord/gateway.rs

@@ -0,0 +1,200 @@
+use futures::StreamExt;
+use libpk::_config::ClusterSettings;
+use metrics::counter;
+use std::sync::{mpsc::Sender, Arc};
+use tracing::{error, info, warn};
+use twilight_gateway::{
+    create_iterator, ConfigBuilder, Event, EventTypeFlags, Message, Shard, ShardId,
+};
+use twilight_model::gateway::{
+    payload::outgoing::update_presence::UpdatePresencePayload,
+    presence::{Activity, ActivityType, Status},
+    Intents,
+};
+
+use crate::discord::identify_queue::{self, RedisQueue};
+
+use super::{cache::DiscordCache, shard_state::ShardStateManager};
+
+pub fn cluster_config() -> ClusterSettings {
+    libpk::config
+        .discord
+        .as_ref()
+        .expect("missing discord config")
+        .cluster
+        .clone()
+        .unwrap_or(libpk::_config::ClusterSettings {
+            node_id: 0,
+            total_shards: 1,
+            total_nodes: 1,
+        })
+}
+
+pub fn create_shards(redis: fred::clients::RedisPool) -> anyhow::Result<Vec<Shard<RedisQueue>>> {
+    let intents = Intents::GUILDS
+        | Intents::DIRECT_MESSAGES
+        | Intents::DIRECT_MESSAGE_REACTIONS
+        | Intents::GUILD_MESSAGES
+        | Intents::GUILD_MESSAGE_REACTIONS
+        | Intents::MESSAGE_CONTENT;
+
+    let queue = identify_queue::new(redis);
+
+    let cluster_settings = cluster_config();
+
+    let (start_shard, end_shard): (u32, u32) = if cluster_settings.total_shards < 16 {
+        warn!("we have less than 16 shards, assuming single gateway process");
+        (0, (cluster_settings.total_shards - 1).into())
+    } else {
+        (
+            (cluster_settings.node_id * 16).into(),
+            (((cluster_settings.node_id + 1) * 16) - 1).into(),
+        )
+    };
+
+    let shards = create_iterator(
+        start_shard..end_shard + 1,
+        cluster_settings.total_shards,
+        ConfigBuilder::new(
+            libpk::config
+                .discord
+                .as_ref()
+                .expect("missing discord config")
+                .bot_token
+                .to_owned(),
+            intents,
+        )
+        .presence(presence("pk;help", false))
+        .queue(queue.clone())
+        .build(),
+        |_, builder| builder.build(),
+    );
+
+    let mut shards_vec = Vec::new();
+    shards_vec.extend(shards);
+
+    Ok(shards_vec)
+}
+
+pub async fn runner(
+    mut shard: Shard<RedisQueue>,
+    _tx: Sender<(ShardId, String)>,
+    shard_state: ShardStateManager,
+    cache: Arc<DiscordCache>,
+) {
+    // let _span = info_span!("shard_runner", shard_id = shard.id().number()).entered();
+    info!("waiting for events");
+    while let Some(item) = shard.next().await {
+        let raw_event = match item {
+            Ok(evt) => match evt {
+                Message::Close(frame) => {
+                    info!(
+                        "shard {} closed: {}",
+                        shard.id().number(),
+                        if let Some(close) = frame {
+                            format!("{} ({})", close.code, close.reason)
+                        } else {
+                            "unknown".to_string()
+                        }
+                    );
+                    if let Err(error) = shard_state.socket_closed(shard.id().number()).await {
+                        error!("failed to update shard state for socket closure: {error}");
+                    }
+                    continue;
+                }
+                Message::Text(text) => text,
+            },
+            Err(error) => {
+                tracing::warn!(?error, "error receiving event from shard {}", shard.id());
+                continue;
+            }
+        };
+
+        let event = match twilight_gateway::parse(raw_event.clone(), EventTypeFlags::all()) {
+            Ok(Some(parsed)) => Event::from(parsed),
+            Ok(None) => {
+                // we received an event type unknown to twilight
+                // that's fine, we probably don't need it anyway
+                continue;
+            }
+            Err(error) => {
+                error!(
+                    "shard {} failed to parse gateway event: {}",
+                    shard.id().number(),
+                    error
+                );
+                continue;
+            }
+        };
+
+        // log the event in metrics
+        // event_type * shard_id is too many labels and prometheus fails to query it
+        // so we split it into two metrics
+        counter!(
+            "pluralkit_gateway_events_type",
+            "event_type" => serde_variant::to_variant_name(&event.kind()).unwrap(),
+        )
+        .increment(1);
+        counter!(
+            "pluralkit_gateway_events_shard",
+            "shard_id" => shard.id().number().to_string(),
+        )
+        .increment(1);
+
+        // update shard state and discord cache
+        if let Err(error) = shard_state
+            .handle_event(shard.id().number(), event.clone())
+            .await
+        {
+            tracing::warn!(?error, "error updating redis state");
+        }
+        // need to do heartbeat separately, to get the latency
+        if let Event::GatewayHeartbeatAck = event
+            && let Err(error) = shard_state
+                .heartbeated(shard.id().number(), shard.latency())
+                .await
+        {
+            tracing::warn!(?error, "error updating redis state for latency");
+        }
+
+        if let Event::Ready(_) = event {
+            if !cache.2.read().await.contains(&shard.id().number()) {
+                cache.2.write().await.push(shard.id().number());
+            }
+        }
+        cache.0.update(&event);
+
+        // okay, we've handled the event internally, let's send it to consumers
+        // tx.send((shard.id(), raw_event)).unwrap();
+    }
+}
+
+pub fn presence(status: &str, going_away: bool) -> UpdatePresencePayload {
+    UpdatePresencePayload {
+        activities: vec![Activity {
+            application_id: None,
+            assets: None,
+            buttons: vec![],
+            created_at: None,
+            details: None,
+            id: None,
+            state: None,
+            url: None,
+            emoji: None,
+            flags: None,
+            instance: None,
+            kind: ActivityType::Playing,
+            name: status.to_string(),
+            party: None,
+            secrets: None,
+            timestamps: None,
+        }],
+        afk: false,
+        since: None,
+        status: if going_away {
+            Status::Idle
+        } else {
+            Status::Online
+        },
+    }
+}

crates/gateway/src/discord/identify_queue.rs

@@ -0,0 +1,88 @@
+use fred::{
+    clients::RedisPool,
+    error::RedisError,
+    interfaces::KeysInterface,
+    types::{Expiration, SetOptions},
+};
+use std::fmt::Debug;
+use std::time::Duration;
+use tokio::sync::oneshot;
+use tracing::{error, info};
+use twilight_gateway::queue::Queue;
+
+pub fn new(redis: RedisPool) -> RedisQueue {
+    RedisQueue {
+        redis,
+        concurrency: libpk::config
+            .discord
+            .as_ref()
+            .expect("missing discord config")
+            .max_concurrency,
+    }
+}
+
+#[derive(Clone)]
+pub struct RedisQueue {
+    pub redis: RedisPool,
+    pub concurrency: u32,
+}
+
+impl Debug for RedisQueue {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("RedisQueue")
+            .field("concurrency", &self.concurrency)
+            .finish()
+    }
+}
+
+impl Queue for RedisQueue {
+    fn enqueue<'a>(&'a self, shard_id: u32) -> oneshot::Receiver<()> {
+        let (tx, rx) = oneshot::channel();
+
+        tokio::spawn(request_inner(
+            self.redis.clone(),
+            self.concurrency,
+            shard_id,
+            tx,
+        ));
+
+        rx
+    }
+}
+
+const EXPIRY: i64 = 6;
+const RETRY_INTERVAL: u64 = 500;
+
+async fn request_inner(redis: RedisPool, concurrency: u32, shard_id: u32, tx: oneshot::Sender<()>) {
+    let bucket = shard_id % concurrency;
+    let key = format!("pluralkit:identify:{}", bucket);
+
+    info!(shard_id, bucket, "waiting for allowance...");
+    loop {
+        let done: Result<Option<String>, RedisError> = redis
+            .set(
+                key.to_string(),
+                "1",
+                Some(Expiration::EX(EXPIRY)),
+                Some(SetOptions::NX),
+                false,
+            )
+            .await;
+        match done {
+            Ok(Some(_)) => {
+                info!(shard_id, bucket, "got allowance!");
+                // if this fails, it's probably already doing something else
+                let _ = tx.send(());
+                return;
+            }
+            Ok(None) => {
+                // not allowed yet, waiting
+            }
+            Err(e) => {
+                error!(shard_id, bucket, "error getting shard allowance: {}", e)
+            }
+        }
+
+        tokio::time::sleep(Duration::from_millis(RETRY_INTERVAL)).await;
+    }
+}

crates/gateway/src/discord/mod.rs

@@ -0,0 +1,4 @@
+pub mod cache;
+pub mod gateway;
+pub mod identify_queue;
+pub mod shard_state;

crates/gateway/src/discord/shard_state.rs

@@ -0,0 +1,91 @@
+use fred::{clients::RedisPool, interfaces::HashesInterface};
+use metrics::{counter, gauge};
+use tracing::info;
+use twilight_gateway::{Event, Latency};
+
+use libpk::{state::*, util::redis::*};
+
+#[derive(Clone)]
+pub struct ShardStateManager {
+    redis: RedisPool,
+}
+
+pub fn new(redis: RedisPool) -> ShardStateManager {
+    ShardStateManager { redis }
+}
+
+impl ShardStateManager {
+    pub async fn handle_event(&self, shard_id: u32, event: Event) -> anyhow::Result<()> {
+        match event {
+            Event::Ready(_) => self.ready_or_resumed(shard_id, false).await,
+            Event::Resumed => self.ready_or_resumed(shard_id, true).await,
+            _ => Ok(()),
+        }
+    }
+
+    async fn get_shard(&self, shard_id: u32) -> anyhow::Result<ShardState> {
+        let data: Option<String> = self
+            .redis
+            .hget("pluralkit:shardstatus", shard_id)
+            .await
+            .to_option_or_error()?;
+        match data {
+            Some(buf) => Ok(serde_json::from_str(&buf).expect("could not decode shard data!")),
+            None => Ok(ShardState::default()),
+        }
+    }
+
+    async fn save_shard(&self, shard_id: u32, info: ShardState) -> anyhow::Result<()> {
+        self.redis
+            .hset::<(), &str, (String, String)>(
+                "pluralkit:shardstatus",
+                (
+                    shard_id.to_string(),
+                    serde_json::to_string(&info).expect("could not serialize shard"),
+                ),
+            )
+            .await?;
+        Ok(())
+    }
+
+    async fn ready_or_resumed(&self, shard_id: u32, resumed: bool) -> anyhow::Result<()> {
+        info!(
+            "shard {} {}",
+            shard_id,
+            if resumed { "resumed" } else { "ready" }
+        );
+        counter!(
+            "pluralkit_gateway_shard_reconnect",
+            "shard_id" => shard_id.to_string(),
+            "resumed" => resumed.to_string(),
+        )
+        .increment(1);
+        gauge!("pluralkit_gateway_shard_up").increment(1);
+        let mut info = self.get_shard(shard_id).await?;
+        info.last_connection = chrono::offset::Utc::now().timestamp() as i32;
+        info.up = true;
+        self.save_shard(shard_id, info).await?;
+        Ok(())
+    }
+
+    pub async fn socket_closed(&self, shard_id: u32) -> anyhow::Result<()> {
+        gauge!("pluralkit_gateway_shard_up").decrement(1);
+        let mut info = self.get_shard(shard_id).await?;
+        info.up = false;
+        info.disconnection_count += 1;
+        self.save_shard(shard_id, info).await?;
+        Ok(())
+    }
+
+    pub async fn heartbeated(&self, shard_id: u32, latency: &Latency) -> anyhow::Result<()> {
+        let mut info = self.get_shard(shard_id).await?;
+        info.up = true;
+        info.last_heartbeat = chrono::offset::Utc::now().timestamp() as i32;
+        info.latency = latency
+            .recent()
+            .first()
+            .map_or_else(|| 0, |d| d.as_millis()) as i32;
+        self.save_shard(shard_id, info).await?;
+        Ok(())
+    }
+}

crates/gateway/src/logger.rs

@@ -0,0 +1,72 @@
+use std::time::Instant;
+
+use axum::{
+    extract::MatchedPath, extract::Request, http::StatusCode, middleware::Next, response::Response,
+};
+use metrics::{counter, histogram};
+use tracing::{info, span, warn, Instrument, Level};
+
+// log any requests that take longer than 2 seconds
+// todo: change as necessary
+const MIN_LOG_TIME: u128 = 2_000;
+
+pub async fn logger(request: Request, next: Next) -> Response {
+    let method = request.method().clone();
+
+    let endpoint = request
+        .extensions()
+        .get::<MatchedPath>()
+        .cloned()
+        .map(|v| v.as_str().to_string())
+        .unwrap_or("unknown".to_string());
+
+    let uri = request.uri().clone();
+
+    let request_id_span = span!(
+        Level::INFO,
+        "request",
+        method = method.as_str(),
+        endpoint = endpoint.clone(),
+    );
+
+    let start = Instant::now();
+    let response = next.run(request).instrument(request_id_span).await;
+    let elapsed = start.elapsed().as_millis();
+
+    counter!(
+        "pluralkit_gateway_cache_api_requests",
+        "method" => method.to_string(),
+        "endpoint" => endpoint.clone(),
+        "status" => response.status().to_string(),
+    )
+    .increment(1);
+    histogram!(
+        "pluralkit_gateway_cache_api_requests_bucket",
+        "method" => method.to_string(),
+        "endpoint" => endpoint.clone(),
+        "status" => response.status().to_string(),
+    )
+    .record(elapsed as f64 / 1_000_f64);
+
+    if response.status() != StatusCode::FOUND {
+        info!(
+            "{} handled request for {} {} in {}ms",
+            response.status(),
+            method,
+            uri.path(),
+            elapsed
+        );
+    }
+
+    if elapsed > MIN_LOG_TIME {
+        warn!(
+            "request to {} full path {} (endpoint {}) took a long time ({}ms)!",
+            method,
+            uri.path(),
+            endpoint,
+            elapsed
+        )
+    }
+
+    response
+}

crates/gateway/src/main.rs

@@ -0,0 +1,140 @@
+#![feature(let_chains)]
+#![feature(if_let_guard)]
+
+use chrono::Timelike;
+use fred::{clients::RedisPool, interfaces::*};
+use signal_hook::{
+    consts::{SIGINT, SIGTERM},
+    iterator::Signals,
+};
+use std::{
+    sync::{mpsc::channel, Arc},
+    time::Duration,
+    vec::Vec,
+};
+use tokio::task::JoinSet;
+use tracing::{info, warn};
+use twilight_gateway::{MessageSender, ShardId};
+use twilight_model::gateway::payload::outgoing::UpdatePresence;
+
+mod cache_api;
+mod discord;
+mod logger;
+
+libpk::main!("gateway");
+async fn real_main() -> anyhow::Result<()> {
+    let (shutdown_tx, shutdown_rx) = channel::<()>();
+    let shutdown_tx = Arc::new(shutdown_tx);
+
+    let redis = libpk::db::init_redis().await?;
+
+    let shard_state = discord::shard_state::new(redis.clone());
+    let cache = Arc::new(discord::cache::new());
+
+    let shards = discord::gateway::create_shards(redis.clone())?;
+
+    let (event_tx, _event_rx) = channel();
+
+    let mut senders = Vec::new();
+    let mut signal_senders = Vec::new();
+
+    let mut set = JoinSet::new();
+    for shard in shards {
+        senders.push((shard.id(), shard.sender()));
+        signal_senders.push(shard.sender());
+        set.spawn(tokio::spawn(discord::gateway::runner(
+            shard,
+            event_tx.clone(),
+            shard_state.clone(),
+            cache.clone(),
+        )));
+    }
+
+    set.spawn(tokio::spawn(
+        async move { scheduled_task(redis, senders).await },
+    ));
+
+    // todo: probably don't do it this way
+    let api_shutdown_tx = shutdown_tx.clone();
+    set.spawn(tokio::spawn(async move {
+        match cache_api::run_server(cache).await {
+            Err(error) => {
+                tracing::error!(?error, "failed to serve cache api");
+                let _ = api_shutdown_tx.send(());
+            }
+            _ => unreachable!(),
+        }
+    }));
+
+    let mut signals = Signals::new(&[SIGINT, SIGTERM])?;
+
+    set.spawn(tokio::spawn(async move {
+        for sig in signals.forever() {
+            info!("received signal {:?}", sig);
+
+            let presence = UpdatePresence {
+                op: twilight_model::gateway::OpCode::PresenceUpdate,
+                d: discord::gateway::presence("Restarting... (please wait)", true),
+            };
+
+            for sender in signal_senders.iter() {
+                let presence = presence.clone();
+                let _ = sender.command(&presence);
+            }
+
+            let _ = shutdown_tx.send(());
+            break;
+        }
+    }));
+
+    let _ = shutdown_rx.recv();
+
+    // sleep 500ms to allow everything to clean up properly
+    tokio::time::sleep(Duration::from_millis(500)).await;
+
+    set.abort_all();
+
+    info!("gateway exiting, have a nice day!");
+
+    Ok(())
+}
+
+async fn scheduled_task(redis: RedisPool, senders: Vec<(ShardId, MessageSender)>) {
+    loop {
+        tokio::time::sleep(Duration::from_secs(
+            (60 - chrono::offset::Utc::now().second()).into(),
+        ))
+        .await;
+        info!("running per-minute scheduled tasks");
+
+        let status: Option<String> = match redis.get("pluralkit:botstatus").await {
+            Ok(val) => Some(val),
+            Err(error) => {
+                tracing::warn!(?error, "failed to fetch bot status from redis");
+                None
+            }
+        };
+
+        let presence = UpdatePresence {
+            op: twilight_model::gateway::OpCode::PresenceUpdate,
+            d: discord::gateway::presence(
+                if let Some(status) = status {
+                    format!("pk;help | {}", status)
+                } else {
+                    "pk;help".to_string()
+                }
+                .as_str(),
+                false,
+            ),
+        };
+
+        for sender in senders.iter() {
+            match sender.1.command(&presence) {
+                Err(error) => {
+                    warn!(?error, "could not update presence on shard {}", sender.0)
+                }
+                _ => {}
+            };
+        }
+    }
+}