opencode/packages/core/src/bus.ts

908 lines
39 KiB
TypeScript

export * as Bus from "./bus.js"
import { Cause, Clock, Context, Effect, Layer, Option, PubSub, Schema, Stream } from "effect"
import { Event } from "@opencode-ai/schema/event"
import type { EventLog } from "@opencode-ai/schema/event-log"
import { and, asc, eq, gt, lte, sql } from "drizzle-orm"
import { Database } from "./database/database.js"
import { EventSequenceTable, EventTable } from "./event/sql.js"
import type { Location } from "@opencode-ai/schema/location"
import { KeyedMutex } from "./effect/keyed-mutex.js"
import { makeGlobalNode } from "@opencode-ai/util/effect/app-node"
import { isDeepStrictEqual } from "node:util"
import { Durable } from "@opencode-ai/schema/durable-event-manifest"
import { SessionEvent } from "@opencode-ai/schema/session-event"
import type { SessionID } from "@opencode-ai/schema/session-id"
import { AbsolutePath } from "@opencode-ai/schema/schema"
export type Subscriber<D extends Event.Definition = Event.Definition> = (event: Event.Payload<D>) => Effect.Effect<void>
export type Unsubscribe = Effect.Effect<void>
export const latestSequence = Effect.fn("Bus.latestSequence")(function* (
db: Database.Interface["db"],
aggregateID: string,
) {
const row = yield* db
.select({ seq: EventSequenceTable.seq })
.from(EventSequenceTable)
.where(eq(EventSequenceTable.aggregate_id, aggregateID))
.get()
.pipe(Effect.orDie)
return row?.seq ?? -1
})
export const reserveSequence = Effect.fn("Bus.reserveSequence")(function* (
db: Database.Interface["db"],
aggregateID: string,
seq: number,
) {
yield* db
.insert(EventSequenceTable)
.values([{ aggregate_id: aggregateID, seq }])
.onConflictDoUpdate({
target: EventSequenceTable.aggregate_id,
set: { seq: sql`max(${EventSequenceTable.seq}, ${seq})` },
})
.run()
.pipe(Effect.orDie)
})
export type SerializedEvent = {
readonly id: Event.ID
readonly type: string
readonly created?: number
readonly seq: number
readonly aggregateID: string
readonly data: Record<string, unknown>
}
export class InvalidDurableEventError extends Schema.TaggedError<InvalidDurableEventError>()(
"Bus.InvalidDurableEvent",
{
type: Schema.String,
message: Schema.String,
},
) {}
const envelope = (aggregateID: string, seq: number, version: number) => ({
aggregateID,
seq: Event.Seq.make(seq),
version: Event.Version.make(version),
})
const decodeSerializedEvent = (event: SerializedEvent): Event.Payload => {
const definition = Durable.get(event.type)
if (!definition?.durable) {
throw new InvalidDurableEventError({ type: event.type, message: `Unknown durable event type ${event.type}` })
}
return {
id: event.id,
created: event.created ?? 0,
type: definition.type,
durable: envelope(event.aggregateID, event.seq, definition.durable.version),
data: Schema.decodeUnknownSync(definition.data)(event.data),
}
}
export const versionedType = Event.versionedType
export const durable = Event.durable
export const ephemeral = Event.ephemeral
export interface PublishOptions {
readonly id?: Event.ID
readonly metadata?: Record<string, unknown>
readonly location?: Location.Ref
readonly global?: boolean
/** Local operational projection committed atomically with a new durable event. Not replayed or serialized. */
readonly commit?: (seq: number) => Effect.Effect<void>
}
export type PublishInput<D extends Event.DurableDefinition = Event.DurableDefinition> = readonly [
definition: D,
data: Event.Data<D>,
options?: PublishOptions,
]
export type PublishResult<I extends readonly PublishInput[]> = {
readonly [K in keyof I]: I[K] extends PublishInput<infer D> ? Event.Payload<D> : never
}
/** Marker/event union emitted by `log`. */
export type LogItem = Event.Payload | EventLog.Synced
export const isSynced = (item: LogItem): item is EventLog.Synced => item.type === "log.synced"
export type SubscribePayload<D extends readonly Event.Definition[]> = D[number] extends infer Item
? Item extends Event.Definition
? Event.Payload<Item>
: never
: never
export interface Subscribe {
/**
* Volatile live channel: every event published from now on, nothing before or
* across a disconnect. Consumers that need reliability combine it with `log`.
* With an ambient Location, delivery is restricted to that Location and global
* events. Unlocated Session events use the Session's owner at publication time.
* Session moves reach both the old and new Location, without changing the event.
*/
(): Stream.Stream<Event.Payload>
<D extends Event.Definition>(definition: D): Stream.Stream<Event.Payload<D>>
<const D extends readonly [Event.Definition, ...Event.Definition[]]>(
definitions: D,
): Stream.Stream<SubscribePayload<D>>
}
const isDefinition = (input: Event.Definition | readonly Event.Definition[]): input is Event.Definition =>
!Array.isArray(input)
export interface Interface {
readonly publish: <D extends Event.Definition>(
definition: D,
data: Event.Data<D>,
options?: PublishOptions,
) => Effect.Effect<Event.Payload<D>>
readonly publishAll: <const I extends readonly [PublishInput, ...PublishInput[]]>(
events: I,
) => Effect.Effect<PublishResult<I>>
readonly subscribe: Subscribe
/**
* Durable, ordered per-aggregate log read. Forked aggregates may reserve an
* inherited prefix before their first child-authored event. `follow: false`
* completes at the end of the log; `follow: true` replays then transitions
* to live. Both modes emit one `Synced` marker at the captured replay
* watermark.
*/
readonly log: (input: {
readonly aggregateID: string
readonly after?: number
readonly follow?: boolean
}) => Stream.Stream<LogItem>
/** @deprecated Use `subscribe()` and consume the returned stream. */
readonly listen: (listener: Subscriber) => Effect.Effect<Unsubscribe>
readonly project: <D extends Event.Definition>(definition: D, projector: Subscriber<D>) => Effect.Effect<void>
readonly replay: (
event: SerializedEvent,
options?: { readonly publish?: boolean; readonly ownerID?: string; readonly strictOwner?: boolean },
) => Effect.Effect<void>
readonly remove: (aggregateID: string) => Effect.Effect<void>
readonly claim: (aggregateID: string, ownerID: string) => Effect.Effect<void>
}
export class Service extends Context.Service<Service, Interface>()("@opencode/Bus") {}
interface Options {
readonly beforeAggregateRead?: (aggregateID: string) => Effect.Effect<void>
/** Maximum durable rows read per page while replaying or tailing an aggregate log. */
readonly logReadPageSize?: number
/** Retain durable event payloads for historical log reads and replay. */
readonly persist?: boolean
}
export function configured(options?: Options) {
return makeGlobalNode({
service: Service,
deps: [Database.node],
layer: Layer.effect(
Service,
Effect.gen(function* () {
// Deferred import: a static one would close the module cycle
// bus → location → project → bus and hit the node bindings in TDZ.
const { Location } = yield* Effect.promise(() => import("./location.js"))
const { SessionTable } = yield* Effect.promise(() => import("./session/sql.js"))
const pubsub = {
live: yield* PubSub.unbounded<Event.Payload>(),
durable: new Map<string, Set<PubSub.PubSub<void>>>(),
typed: new Map<string, PubSub.PubSub<Event.Payload>>(),
}
const projectors = new Map<string, Subscriber[]>()
const listeners = new Array<Subscriber>()
const durableLocks = KeyedMutex.makeUnsafe<string>()
const { db } = yield* Database.Service
const logReadPageSize = options?.logReadPageSize ?? 512
const persist = options?.persist ?? false
const sessions = new Map<SessionID, Location.Ref>()
// Keep routing separate from the public event, and retain its snapshot
// while a slow subscriber drains events queued before a move or deletion.
const routes = new WeakMap<Event.Payload, readonly Location.Ref[]>()
const isSessionEvent = (event: Event.Payload): event is SessionEvent.Event =>
Object.hasOwn(SessionEvent.All.cases, event.type)
const prepareRoutes = Effect.fnUntraced(function* (events: readonly Event.Payload[]) {
const updates = new Map<SessionID, Location.Ref | undefined>()
const resolved = new Map<Event.Payload, readonly Location.Ref[]>()
for (const event of events) {
if (!isSessionEvent(event)) continue
const id = event.data.sessionID
if (event.type === "session.created") {
updates.set(id, event.data.location)
resolved.set(event, [event.location ?? event.data.location])
continue
}
if (event.location && event.type !== "session.forked" && event.type !== "session.moved") {
if (event.type === "session.deleted") updates.set(id, undefined)
continue
}
const owner = event.type === "session.forked" ? event.data.parentID : id
let ref = updates.has(owner) ? updates.get(owner) : sessions.get(owner)
if (!ref && !updates.has(owner)) {
const row = yield* db
.select({ directory: SessionTable.directory, workspaceID: SessionTable.workspace_id })
.from(SessionTable)
.where(eq(SessionTable.id, owner))
.get()
.pipe(Effect.orDie)
ref = row
? { directory: AbsolutePath.make(row.directory), workspaceID: row.workspaceID ?? undefined }
: undefined
updates.set(owner, ref)
}
if (event.type === "session.moved") {
// Both owners need the transition, even if the producer supplied
// an envelope location. Later events use only the destination.
updates.set(id, event.data.location)
resolved.set(event, ref ? [ref, event.data.location] : [event.data.location])
continue
}
if (event.type === "session.forked") updates.set(id, ref)
resolved.set(event, event.location ? [event.location] : ref ? [ref] : [])
if (event.type === "session.deleted") updates.set(id, undefined)
}
// Apply only after the projection transaction commits. A failed move
// must not redirect events away from the Session's actual location.
return () => {
for (const [id, ref] of updates) {
if (ref) sessions.set(id, ref)
else sessions.delete(id)
}
for (const [event, ref] of resolved) routes.set(event, ref)
}
})
const getOrCreate = (definition: Event.Definition) =>
Effect.gen(function* () {
const existing = pubsub.typed.get(definition.type)
if (existing) return existing
const created = yield* PubSub.unbounded<Event.Payload>()
pubsub.typed.set(definition.type, created)
return created
})
yield* Effect.addFinalizer(() =>
Effect.gen(function* () {
yield* PubSub.shutdown(pubsub.live)
yield* Effect.forEach(
pubsub.durable.values(),
(pubsubs) => Effect.forEach(pubsubs, PubSub.shutdown, { discard: true }),
{ discard: true },
)
yield* Effect.forEach(pubsub.typed.values(), PubSub.shutdown, { discard: true })
}),
)
function commitDurableEvent(
definition: Event.Definition,
event: Event.Payload,
input?: {
readonly seq: number
readonly aggregateID: string
readonly ownerID?: string
readonly strictOwner?: boolean
},
commit?: (seq: number) => Effect.Effect<void>,
) {
return Effect.gen(function* () {
const durable = definition.durable
if (!durable) return yield* Effect.void
const aggregateID = (event.data as Record<string, unknown>)[durable.aggregate]
if (typeof aggregateID !== "string")
return yield* Effect.die(
new InvalidDurableEventError({
type: event.type,
message: `Expected string aggregate field ${durable.aggregate}`,
}),
)
if (input && input.aggregateID !== aggregateID) {
yield* Effect.die(
new InvalidDurableEventError({
type: event.type,
message: `Aggregate mismatch: expected ${input.aggregateID}, got ${aggregateID}`,
}),
)
}
const list = projectors.get(versionedType(definition.type, durable.version)) ?? []
return yield* Effect.uninterruptible(
Effect.gen(function* () {
const committed = yield* db
.transaction(
() =>
Effect.gen(function* () {
const row = yield* db
.select({ seq: EventSequenceTable.seq, ownerID: EventSequenceTable.owner_id })
.from(EventSequenceTable)
.where(eq(EventSequenceTable.aggregate_id, aggregateID))
.get()
.pipe(Effect.orDie)
const latest = row?.seq ?? -1
const encoded = Schema.encodeUnknownSync(definition.data)(event.data) as Record<string, unknown>
if (input?.strictOwner && row?.ownerID && row.ownerID !== input.ownerID) {
yield* Effect.die(
new InvalidDurableEventError({
type: event.type,
message: `Replay owner mismatch for aggregate ${aggregateID}: expected ${row.ownerID}, got ${input.ownerID ?? "none"}`,
}),
)
}
if (input && input.seq <= latest) {
if (!persist) return
const stored = yield* db
.select()
.from(EventTable)
.where(and(eq(EventTable.aggregate_id, aggregateID), eq(EventTable.seq, input.seq)))
.get()
.pipe(Effect.orDie)
if (
stored?.id === event.id &&
stored.type === versionedType(definition.type, durable.version) &&
stored.created === (event.created ?? 0) &&
isDeepStrictEqual(stored.data, encoded)
) {
if (input.ownerID && row?.ownerID == null) {
yield* db
.update(EventSequenceTable)
.set({ owner_id: input.ownerID })
.where(eq(EventSequenceTable.aggregate_id, aggregateID))
.run()
.pipe(Effect.orDie)
}
return
}
yield* Effect.die(
new InvalidDurableEventError({
type: event.type,
message: `Replay diverged at aggregate ${aggregateID} sequence ${input.seq}`,
}),
)
}
if (input && row?.ownerID && row.ownerID !== input.ownerID) {
return
}
const seq = input?.seq ?? latest + 1
if (input && seq !== latest + 1) {
yield* Effect.die(
new InvalidDurableEventError({
type: event.type,
message: `Sequence mismatch for aggregate ${aggregateID}: expected ${latest + 1}, got ${seq}`,
}),
)
}
if (persist) {
const stored = yield* db
.select({ aggregateID: EventTable.aggregate_id, seq: EventTable.seq })
.from(EventTable)
.where(eq(EventTable.id, event.id))
.get()
.pipe(Effect.orDie)
if (stored)
yield* Effect.die(
new InvalidDurableEventError({
type: event.type,
message: `Event ${event.id} already exists at aggregate ${stored.aggregateID} sequence ${stored.seq}`,
}),
)
}
const committed = {
...event,
durable: { aggregateID, seq, version: durable.version },
} as Event.Payload
const route = yield* prepareRoutes([committed])
for (const projector of list) {
yield* projector(committed)
}
if (commit) yield* commit(seq)
yield* db
.insert(EventSequenceTable)
.values([{ aggregate_id: aggregateID, seq, owner_id: input?.ownerID }])
.onConflictDoUpdate({
target: EventSequenceTable.aggregate_id,
set: {
seq: sql`max(${EventSequenceTable.seq}, ${seq})`,
...(input?.ownerID && row?.ownerID == null ? { owner_id: input.ownerID } : {}),
},
})
.run()
.pipe(Effect.orDie)
if (persist)
yield* db
.insert(EventTable)
.values([
{
id: event.id,
aggregate_id: aggregateID,
seq,
created: event.created ?? 0,
type: versionedType(definition.type, durable.version),
data: encoded,
},
])
.run()
.pipe(Effect.orDie)
return { aggregateID, seq, event: committed, route }
}),
{ behavior: "immediate" },
)
.pipe(Effect.orDie)
if (committed) {
committed.route()
yield* Effect.forEach(
pubsub.durable.get(committed.aggregateID) ?? [],
(wake) => PubSub.publish(wake, undefined),
{ discard: true },
)
}
return committed
}),
)
})
}
function publishEvent<D extends Event.Definition>(
definition: D,
event: Event.Payload<D>,
commit?: PublishOptions["commit"],
) {
return Effect.gen(function* () {
if (!definition.durable && commit)
return yield* Effect.die(
new InvalidDurableEventError({
type: event.type,
message: "Local commit hooks require a durable event",
}),
)
if (definition.durable) {
const aggregateID = (event.data as Record<string, unknown>)[definition.durable.aggregate]
if (typeof aggregateID !== "string")
return yield* commitDurableEvent(definition, event as Event.Payload, undefined, commit).pipe(
Effect.as(event),
)
return yield* durableLocks.withLock(aggregateID)(
Effect.gen(function* () {
const committed = yield* commitDurableEvent(definition, event as Event.Payload, undefined, commit)
if (!committed) return event
event = committed.event as Event.Payload<D>
yield* notify(event as Event.Payload, true)
return event
}),
)
}
const route = yield* prepareRoutes([event as Event.Payload])
route()
yield* notify(event as Event.Payload, false)
return event
})
}
const observe = (event: Event.Payload, observer: (event: Event.Payload) => Effect.Effect<void>) =>
Effect.suspend(() => observer(event)).pipe(
Effect.catchCauseIf(
(cause) => !Cause.hasInterrupts(cause),
(cause) => Effect.logError("Event listener failed", { eventID: event.id, eventType: event.type, cause }),
),
)
function notify(event: Event.Payload, isolateListeners: boolean) {
return Effect.gen(function* () {
yield* Effect.forEach(
listeners,
(listener) => (isolateListeners ? observe(event, listener) : listener(event)),
{ discard: true },
)
const typed = pubsub.typed.get(event.type)
if (typed) yield* PubSub.publish(typed, event)
yield* PubSub.publish(pubsub.live, event)
})
}
function publish<D extends Event.Definition>(definition: D, data: Event.Data<D>, options?: PublishOptions) {
return Effect.gen(function* () {
const serviceLocation = Option.getOrUndefined(yield* Effect.serviceOption(Location.Service))
const location = options?.global
? undefined
: (options?.location ??
(serviceLocation
? { directory: serviceLocation.directory, workspaceID: serviceLocation.workspaceID }
: undefined))
return yield* publishEvent(
definition,
{
id: options?.id ?? Event.ID.create(),
created: yield* Clock.currentTimeMillis,
...(options?.metadata ? { metadata: options.metadata } : {}),
type: definition.type,
...(location ? { location } : {}),
data,
} as Event.Payload<D>,
options?.commit,
)
})
}
function publishAll<const I extends readonly [PublishInput, ...PublishInput[]]>(events: I) {
return Effect.gen(function* () {
const serviceLocation = Option.getOrUndefined(yield* Effect.serviceOption(Location.Service))
const payloads = yield* Effect.forEach(events, ([definition, data, options]) =>
Effect.gen(function* () {
const aggregateID = (data as Record<string, unknown>)[definition.durable.aggregate]
if (typeof aggregateID !== "string") {
return yield* Effect.die(
new InvalidDurableEventError({
type: definition.type,
message: `Expected string aggregate field ${definition.durable.aggregate}`,
}),
)
}
const location = options?.global
? undefined
: (options?.location ??
(serviceLocation
? { directory: serviceLocation.directory, workspaceID: serviceLocation.workspaceID }
: undefined))
return {
definition,
aggregateID,
commit: options?.commit,
event: {
id: options?.id ?? Event.ID.create(),
created: yield* Clock.currentTimeMillis,
...(options?.metadata ? { metadata: options.metadata } : {}),
type: definition.type,
...(location ? { location } : {}),
data,
} as Event.Payload,
}
}),
)
const aggregateID = payloads[0].aggregateID
if (payloads.some((item) => item.aggregateID !== aggregateID)) {
return yield* Effect.die(
new InvalidDurableEventError({
type: payloads[0].definition.type,
message: "Published events must belong to the same aggregate",
}),
)
}
return yield* durableLocks.withLock(aggregateID)(
Effect.uninterruptible(
Effect.gen(function* () {
const committed = yield* db
.transaction(
() =>
Effect.gen(function* () {
const row = yield* db
.select({ seq: EventSequenceTable.seq })
.from(EventSequenceTable)
.where(eq(EventSequenceTable.aggregate_id, aggregateID))
.get()
.pipe(Effect.orDie)
const firstSeq = (row?.seq ?? -1) + 1
const finalSeq = firstSeq + payloads.length - 1
const queued = payloads.map((item, index) => ({
...item.event,
durable: envelope(aggregateID, firstSeq + index, item.definition.durable.version),
}))
const route = yield* prepareRoutes(queued)
const rows = new Array<typeof EventTable.$inferInsert>()
const ids = new Set<Event.ID>()
for (const [index, item] of payloads.entries()) {
const seq = firstSeq + index
const encoded = Schema.encodeUnknownSync(item.definition.data)(item.event.data) as Record<
string,
unknown
>
if (persist) {
if (ids.has(item.event.id))
yield* Effect.die(
new InvalidDurableEventError({
type: item.event.type,
message: `Event ${item.event.id} appears more than once in the batch`,
}),
)
ids.add(item.event.id)
const stored = yield* db
.select({ aggregateID: EventTable.aggregate_id, seq: EventTable.seq })
.from(EventTable)
.where(eq(EventTable.id, item.event.id))
.get()
.pipe(Effect.orDie)
if (stored)
yield* Effect.die(
new InvalidDurableEventError({
type: item.event.type,
message: `Event ${item.event.id} already exists at aggregate ${stored.aggregateID} sequence ${stored.seq}`,
}),
)
}
const event = queued[index]
for (const projector of projectors.get(
versionedType(item.definition.type, item.definition.durable.version),
) ?? []) {
yield* projector(event)
}
if (item.commit) yield* item.commit(seq)
if (persist)
rows.push({
id: event.id,
aggregate_id: aggregateID,
seq,
created: event.created,
type: versionedType(item.definition.type, item.definition.durable.version),
data: encoded,
})
}
yield* db
.insert(EventSequenceTable)
.values([{ aggregate_id: aggregateID, seq: finalSeq }])
.onConflictDoUpdate({ target: EventSequenceTable.aggregate_id, set: { seq: finalSeq } })
.run()
.pipe(Effect.orDie)
if (persist) yield* db.insert(EventTable).values(rows).run().pipe(Effect.orDie)
return { events: queued, route }
}),
{ behavior: "immediate" },
)
.pipe(Effect.orDie)
committed.route()
yield* Effect.forEach(
pubsub.durable.get(aggregateID) ?? [],
(wake) => PubSub.publish(wake, undefined),
{
discard: true,
},
)
yield* Effect.forEach(committed.events, (event) => notify(event, true), { discard: true })
return committed.events as PublishResult<I>
}),
),
)
})
}
function replay(
event: SerializedEvent,
options?: { readonly publish?: boolean; readonly ownerID?: string; readonly strictOwner?: boolean },
) {
return Effect.gen(function* () {
const definition = Durable.get(event.type)
if (!definition?.durable)
return yield* Effect.die(
new InvalidDurableEventError({ type: event.type, message: `Unknown durable event type ${event.type}` }),
)
yield* durableLocks.withLock(event.aggregateID)(
Effect.gen(function* () {
const payload = {
id: event.id,
created: event.created ?? 0,
type: definition.type,
data: Schema.decodeUnknownSync(definition.data)(event.data),
} as Event.Payload
const committed = yield* commitDurableEvent(definition, payload, {
seq: event.seq,
aggregateID: event.aggregateID,
ownerID: options?.ownerID,
strictOwner: options?.strictOwner,
})
if (committed && options?.publish) {
yield* notify(committed.event, true)
}
}),
)
})
}
function remove(aggregateID: string) {
return db
.transaction(() =>
Effect.gen(function* () {
yield* db.delete(EventSequenceTable).where(eq(EventSequenceTable.aggregate_id, aggregateID)).run()
yield* db.delete(EventTable).where(eq(EventTable.aggregate_id, aggregateID)).run()
}),
)
.pipe(
Effect.tap(() => Effect.sync(() => sessions.delete(aggregateID as SessionID))),
Effect.orDie,
)
}
function claim(aggregateID: string, ownerID: string) {
return db
.update(EventSequenceTable)
.set({ owner_id: ownerID })
.where(eq(EventSequenceTable.aggregate_id, aggregateID))
.run()
.pipe(Effect.orDie)
}
const local = <A extends Event.Payload>(stream: Stream.Stream<A>) =>
Stream.unwrap(
Effect.serviceOption(Location.Service).pipe(
Effect.map((location) =>
Option.match(location, {
onNone: () => stream,
onSome: (location) => {
const matches = (ref: Location.Ref) =>
ref.directory === location.directory && ref.workspaceID === location.workspaceID
return stream.pipe(
Stream.filter((event) => {
const refs = routes.get(event)
if (refs) return refs.some(matches)
return !event.location || matches(event.location)
}),
)
},
}),
),
),
)
function subscribe(): Stream.Stream<Event.Payload>
function subscribe<D extends Event.Definition>(definition: D): Stream.Stream<Event.Payload<D>>
function subscribe<const D extends readonly [Event.Definition, ...Event.Definition[]]>(
definitions: D,
): Stream.Stream<SubscribePayload<D>>
function subscribe(input?: Event.Definition | readonly Event.Definition[]): Stream.Stream<Event.Payload> {
if (input === undefined) return streamLive()
if (isDefinition(input)) {
return local(Stream.unwrap(getOrCreate(input).pipe(Effect.map((pubsub) => Stream.fromPubSub(pubsub)))))
}
const types = new Set(input.map((definition) => definition.type))
return streamLive().pipe(Stream.filter((event) => types.has(event.type)))
}
const streamLive = (): Stream.Stream<Event.Payload> => local(Stream.fromPubSub(pubsub.live))
const readAfter = (
aggregateID: string,
after: number,
input: { readonly through: number; readonly limit: number },
) =>
(options?.beforeAggregateRead?.(aggregateID) ?? Effect.void).pipe(
Effect.andThen(
Effect.suspend(() => {
const query = db
.select()
.from(EventTable)
.where(
and(
eq(EventTable.aggregate_id, aggregateID),
gt(EventTable.seq, after),
lte(EventTable.seq, input.through),
),
)
.orderBy(asc(EventTable.seq))
return query.limit(input.limit).all()
}),
),
Effect.orDie,
// Skip types missing from the durable manifest instead of failing the
// read: the aggregate may hold events this process cannot decode. The
// raw tail seq keeps cursors advancing across the resulting gaps.
Effect.map((rows) => ({
seq: rows.at(-1)?.seq,
events: rows.flatMap((event) => {
if (!Durable.get(event.type)?.durable) return []
return [
decodeSerializedEvent({
id: event.id,
created: event.created,
aggregateID: event.aggregate_id,
seq: event.seq,
type: event.type,
data: event.data,
}),
]
}),
})),
)
const subscribeDurable = (aggregateID: string) =>
Effect.gen(function* () {
const wake = yield* PubSub.sliding<void>(1)
const subscription = yield* PubSub.subscribe(wake)
yield* Effect.acquireRelease(
Effect.sync(() => {
const wakes = pubsub.durable.get(aggregateID) ?? new Set()
wakes.add(wake)
pubsub.durable.set(aggregateID, wakes)
}),
() =>
Effect.sync(() => {
const wakes = pubsub.durable.get(aggregateID)
wakes?.delete(wake)
if (wakes?.size === 0) pubsub.durable.delete(aggregateID)
}).pipe(Effect.andThen(PubSub.shutdown(wake))),
)
return subscription
})
const log = (input: {
readonly aggregateID: string
readonly after?: number
readonly follow?: boolean
}): Stream.Stream<LogItem> =>
Stream.unwrap(
Effect.gen(function* () {
let sequence = input.after ?? -1
const readThrough = (through: number): Stream.Stream<Event.Payload> =>
Stream.paginate(sequence, (cursor) =>
readAfter(input.aggregateID, cursor, { through, limit: logReadPageSize }).pipe(
Effect.tap((page) =>
Effect.sync(() => {
sequence = page.seq ?? sequence
}),
),
Effect.map(
(page) =>
[
page.events,
page.seq !== undefined && page.seq < through ? Option.some(page.seq) : Option.none<number>(),
] as const,
),
),
)
// Subscribing before the historical read means events committed during
// replay either appear in the read or arrive through a post-marker wake.
const wakes = input.follow ? yield* subscribeDurable(input.aggregateID) : undefined
const target = yield* latestSequence(db, input.aggregateID)
const marker: EventLog.Synced = {
type: "log.synced",
aggregateID: input.aggregateID,
...(target >= 0 ? { seq: Event.Seq.make(target) } : {}),
}
const replay: Stream.Stream<LogItem> = readThrough(target).pipe(Stream.concat(Stream.make(marker)))
if (!wakes) return replay
const live: Stream.Stream<LogItem> = Stream.fromSubscription(wakes).pipe(
Stream.mapEffect(() => latestSequence(db, input.aggregateID)),
Stream.filter((target) => target > sequence),
Stream.flatMap((target) => readThrough(target)),
)
return Stream.concat(replay, live)
}),
)
const listen = (listener: Subscriber): Effect.Effect<Unsubscribe> =>
Effect.sync(() => {
listeners.push(listener)
return Effect.sync(() => {
const index = listeners.indexOf(listener)
if (index >= 0) listeners.splice(index, 1)
})
})
const project = <D extends Event.Definition>(definition: D, projector: Subscriber<D>): Effect.Effect<void> =>
Effect.sync(() => {
const key = definition.durable
? versionedType(definition.type, definition.durable.version)
: definition.type
const list = projectors.get(key) ?? []
list.push((event) => projector(event as Event.Payload<D>))
projectors.set(key, list)
})
return Service.of({
publish,
publishAll,
subscribe,
log,
listen,
project,
replay,
remove,
claim,
})
}),
),
})
}
export const node = configured()