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//! Compaction: replacing the document with a snapshot in a new epoch.
//!
//! * `snapshot`: deterministic snapshot build (step 3).
//! * `records`: the replicated compaction records under `_continuum/compactions/<id>`.
//! * `coordinator`: proposal, settle period and decision on the node that was asked.
//! * `switch`: switching this node to a committed epoch (worker).
//! * `catchup`: rejoining a newer epoch from peers (late, new or failed nodes), then
//! replaying or quarantining this node's own missing changes.
//! * `quarantine`: inspecting, replaying or discarding quarantined changes.
//! * `delta`: replaying this node's changes since the base into the new epoch.
//! * `local`: per-node in-memory state (prebuilt snapshots, switch status, archive).
//! * `api`: `/admin/compaction(s)` handlers.
//!
//! The rest of the node is reached exclusively through [`Host`], so this module never
//! depends on `AppState`, peers or sync internals.
mod api;
mod catchup;
mod coordinator;
mod delta;
mod local;
mod quarantine;
mod records;
pub(crate) mod snapshot;
mod switch;
pub(crate) use local::Compaction;
pub(crate) use switch::run_worker;
use std::future::Future;
use std::sync::Arc;
use std::time::Duration;
use automerge::AutoCommit;
use axum::{
routing::{get, post},
Router,
};
use tokio::sync::broadcast;
use crate::replica::Epoch;
use crate::sync::ChangeSet;
/// What compaction needs from the node. Implemented by `AppState`.
///
/// Used generically (`H: Host`), never as `dyn Host`, so the generic methods are fine.
pub(crate) trait Host: Clone + Send + Sync + 'static {
/// This node's in-memory compaction state.
fn compaction(&self) -> &Compaction;
/// This node's peer ID.
fn node_id(&self) -> String;
/// The epoch of the local replica.
fn current_epoch(&self) -> Epoch;
/// Lower bound and default basis for the settle period.
fn dormant_after(&self) -> Duration;
fn is_node_ready(&self) -> impl Future<Output = bool> + Send;
/// Known (not forgotten) peers.
fn peer_summaries(&self) -> impl Future<Output = Vec<PeerSummary>> + Send;
/// Stops serving requests (back to `Joining`, keeping the cluster ID), as while a
/// rejoin syncs a fresh document. Returns whether the node was serving.
fn suspend(&self) -> impl Future<Output = bool> + Send;
/// Serves requests again after [`Host::suspend`].
fn resume(&self) -> impl Future<Output = ()> + Send;
/// Serves reads from this document (read-only, marked stale) while the node is not
/// ready; `None` ends it.
fn set_stale_view(&self, view: Option<(Epoch, AutoCommit)>);
/// Whether the document caught up with a peer since the last reset.
fn initial_sync_done(&self) -> bool;
/// Makes the next sync count as initial again.
fn reset_initial_sync(&self);
/// Store paths touched by each published document change.
fn subscribe_changes(&self) -> broadcast::Receiver<Arc<ChangeSet>>;
/// Reads the document on the blocking pool.
fn read_doc<T, F>(&self, f: F) -> impl Future<Output = T> + Send
where
F: FnOnce(&AutoCommit) -> T + Send + 'static,
T: Send + 'static;
/// Mutable access to the document without publishing a change (e.g. forks).
fn update_doc<T, F>(&self, f: F) -> impl Future<Output = T> + Send
where
F: FnOnce(&mut AutoCommit) -> T + Send + 'static,
T: Send + 'static;
/// One committed change (rolled back on error), published and replicated.
fn commit_doc<T, E, F>(&self, f: F) -> impl Future<Output = Result<T, E>> + Send
where
F: FnOnce(&mut AutoCommit) -> Result<T, E> + Send + 'static,
T: Send + 'static,
E: Send + 'static;
/// Replaces the document and its epoch atomically. Under the write lock, `f` gets
/// the live document and returns the new one. Afterwards the node resets every
/// peer's sync state and publishes the change. Returns the old document.
fn switch_epoch<E, F>(
&self,
epoch: Epoch,
f: F,
) -> impl Future<Output = Result<AutoCommit, E>> + Send
where
F: FnOnce(&mut AutoCommit) -> Result<AutoCommit, E> + Send + 'static,
E: Send + 'static;
}
#[derive(Clone, Debug)]
pub(crate) struct PeerSummary {
pub(crate) id: String,
/// Not dormant.
pub(crate) active: bool,
/// Handshake completed.
pub(crate) established: bool,
/// The epoch the peer last advertised.
pub(crate) epoch: Option<Epoch>,
}
/// Admin routes. Merged into the authenticated part of the node's router.
pub(crate) fn router<H: Host>() -> Router<H> {
Router::new()
.route(
"/admin/compaction",
post(api::start::<H>).delete(api::abort_current::<H>),
)
.route("/admin/compactions", get(api::list::<H>))
.route(
"/admin/compactions/{id}",
get(api::get::<H>).delete(api::abort::<H>),
)
.route("/admin/epochs", get(api::epochs::<H>))
.route("/admin/quarantine", get(quarantine::list::<H>))
.route(
"/admin/quarantine/{id}",
get(quarantine::get::<H>).delete(quarantine::discard::<H>),
)
.route(
"/admin/quarantine/{id}/document",
get(quarantine::document::<H>),
)
.route(
"/admin/quarantine/{id}/replay",
post(quarantine::replay::<H>),
)
}
|
