Files
openchamber/packages/ui/src/sync/event-pipeline.ts
T

345 lines
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TypeScript

/**
* Event Pipeline — SSE connection, event coalescing, and batched flush.
*
* Plain closure API:
* const { cleanup } = createEventPipeline({ sdk, onEvent })
*
* No class, no start/stop lifecycle. One pipeline per mount.
* Abort controller created once at init, cleaned up via returned cleanup fn.
*/
import type { Event, OpencodeClient } from "@opencode-ai/sdk/v2/client"
import { syncDebug } from "./debug"
// ---------------------------------------------------------------------------
// Types
// ---------------------------------------------------------------------------
export type QueuedEvent = {
directory: string
payload: Event
}
export type FlushHandler = (events: QueuedEvent[]) => void
// ---------------------------------------------------------------------------
// Constants
// ---------------------------------------------------------------------------
const FLUSH_FRAME_MS = 16
const STREAM_YIELD_MS = 8
const RECONNECT_DELAY_MS = 250
const HEARTBEAT_TIMEOUT_MS = 15_000
// ---------------------------------------------------------------------------
// Pipeline factory
// ---------------------------------------------------------------------------
export type EventPipelineInput = {
sdk: OpencodeClient
onEvent: (directory: string, payload: Event) => void
routeDirectory?: (directory: string, payload: Event) => string
/** Called after SSE reconnects (visibility restore or heartbeat timeout). */
onReconnect?: () => void
}
const normalizeEventType = (payload: Event): Event => {
const type = (payload as { type?: unknown }).type
if (typeof type !== "string") {
return payload
}
const match = /^(.*)\.(\d+)$/.exec(type)
if (!match || !match[1]) {
return payload
}
return {
...payload,
type: match[1] as Event["type"],
} as unknown as Event
}
function resolveEventDirectory(event: unknown, payload: Event): string {
const directDirectory =
typeof event === "object" && event !== null && typeof (event as { directory?: unknown }).directory === "string"
? (event as { directory: string }).directory
: null
if (directDirectory && directDirectory.length > 0) {
return directDirectory
}
const properties =
typeof payload.properties === "object" && payload.properties !== null
? (payload.properties as Record<string, unknown>)
: null
const propertyDirectory = typeof properties?.directory === "string" ? properties.directory : null
return propertyDirectory && propertyDirectory.length > 0 ? propertyDirectory : "global"
}
// Per-directory queue state. Each directory owns an independent flush timer
// so a busy directory's delta storm cannot block another directory's events
// from reaching the UI (head-of-line blocking across sessions).
type DirectoryQueue = {
queue: Event[]
buffer: Event[]
coalesced: Map<string, number>
staleDeltas: Set<string>
timer: ReturnType<typeof setTimeout> | undefined
last: number
}
export function createEventPipeline(input: EventPipelineInput) {
const { sdk, onEvent, onReconnect, routeDirectory } = input
const abort = new AbortController()
let hasConnected = false
// One queue + one flush timer per directory. Lazily created on first event.
const directories = new Map<string, DirectoryQueue>()
const getOrCreateDir = (directory: string): DirectoryQueue => {
let d = directories.get(directory)
if (d) return d
d = {
queue: [],
buffer: [],
coalesced: new Map(),
staleDeltas: new Set(),
timer: undefined,
last: 0,
}
directories.set(directory, d)
return d
}
// Coalesce key — same-type events for the same entity replace earlier ones.
// Keys are scoped to a single directory's queue, so directory is implicit.
// message.part.delta is a special case: consecutive deltas for the same
// (messageID, partID, field) are accumulated (string-concatenated) rather
// than replaced, because the reducer is a pure append and merging is
// semantically identical to applying each delta individually.
const key = (payload: Event): string | undefined => {
if (payload.type === "session.status") {
const props = payload.properties as { sessionID: string }
return `session.status:${props.sessionID}`
}
if (payload.type === "lsp.updated") {
return `lsp.updated`
}
if (payload.type === "message.part.updated") {
const part = (payload.properties as { part: { messageID: string; id: string } }).part
return `message.part.updated:${part.messageID}:${part.id}`
}
if (payload.type === "message.part.delta") {
const props = payload.properties as { messageID: string; partID: string; field: string }
return `message.part.delta:${props.messageID}:${props.partID}:${props.field}`
}
return undefined
}
const deltaKey = (messageID: string, partID: string, field: string) => `${messageID}:${partID}:${field}`
// Flush one directory — swap queue, dispatch events.
// React 18 auto-batching still collapses the setState calls inside a single
// directory's flush into one render pass.
const flushDir = (directory: string) => {
const d = directories.get(directory)
if (!d) return
if (d.timer) {
clearTimeout(d.timer)
d.timer = undefined
}
if (d.queue.length === 0) return
const events = d.queue
const staleDeltas = d.staleDeltas.size > 0 ? new Set(d.staleDeltas) : undefined
d.queue = d.buffer
d.buffer = events
d.queue.length = 0
d.coalesced.clear()
d.staleDeltas.clear()
d.last = Date.now()
syncDebug.pipeline.flush(events.length)
for (const payload of events) {
if (staleDeltas && payload.type === "message.part.delta") {
const props = payload.properties as { messageID: string; partID: string; field: string }
if (staleDeltas.has(deltaKey(props.messageID, props.partID, props.field))) {
continue
}
}
onEvent(directory, payload)
}
d.buffer.length = 0
}
const flushAll = () => {
for (const directory of directories.keys()) {
flushDir(directory)
}
}
const scheduleDir = (directory: string) => {
const d = getOrCreateDir(directory)
if (d.timer) return
const elapsed = Date.now() - d.last
d.timer = setTimeout(() => flushDir(directory), Math.max(0, FLUSH_FRAME_MS - elapsed))
}
// Helpers
const wait = (ms: number) => new Promise<void>((resolve) => setTimeout(resolve, ms))
const isAbortError = (error: unknown): boolean =>
error instanceof DOMException && error.name === "AbortError" ||
(typeof error === "object" && error !== null && (error as { name?: string }).name === "AbortError")
let streamErrorLogged = false
let attempt: AbortController | undefined
let lastEventAt = Date.now()
let heartbeat: ReturnType<typeof setTimeout> | undefined
const resetHeartbeat = () => {
lastEventAt = Date.now()
if (heartbeat) clearTimeout(heartbeat)
heartbeat = setTimeout(() => {
attempt?.abort()
}, HEARTBEAT_TIMEOUT_MS)
}
const clearHeartbeat = () => {
if (!heartbeat) return
clearTimeout(heartbeat)
heartbeat = undefined
}
// SSE loop — iterate SDK global event stream, enqueue with coalescing
void (async () => {
while (!abort.signal.aborted) {
attempt = new AbortController()
lastEventAt = Date.now()
const onAbort = () => {
attempt?.abort()
}
abort.signal.addEventListener("abort", onAbort)
try {
const events = await sdk.global.event({
signal: attempt.signal,
onSseError: (error: unknown) => {
if (isAbortError(error)) return
if (streamErrorLogged) return
streamErrorLogged = true
console.error("[event-pipeline] stream error", error)
},
})
if (hasConnected) {
onReconnect?.()
} else {
hasConnected = true
}
let yielded = Date.now()
resetHeartbeat()
// Enqueue event with coalescing + stale delta tracking
for await (const event of events.stream) {
resetHeartbeat()
streamErrorLogged = false
const payload = (event as { payload?: Event }).payload ?? (event as unknown as Event)
if (!payload || typeof payload !== "object" || typeof (payload as { type?: unknown }).type !== "string") {
continue
}
const normalizedPayload = normalizeEventType(payload)
const directory = resolveEventDirectory(event, normalizedPayload)
const routedDirectory = routeDirectory?.(directory, normalizedPayload) || directory
const d = getOrCreateDir(routedDirectory)
const k = key(normalizedPayload)
if (k) {
const i = d.coalesced.get(k)
if (i !== undefined) {
if (normalizedPayload.type === "message.part.delta") {
// Accumulate delta strings — append to the already-queued event
// rather than replacing it. The reducer is a pure string append so
// this is semantically identical to applying each delta separately.
const prev = d.queue[i] as unknown as { properties: { delta: string } }
const inc = normalizedPayload.properties as { delta: string }
d.queue[i] = {
...normalizedPayload,
properties: {
...(normalizedPayload.properties as object),
delta: prev.properties.delta + inc.delta,
},
} as unknown as Event
} else {
d.queue[i] = normalizedPayload
if (normalizedPayload.type === "message.part.updated") {
const part = (normalizedPayload.properties as { part: { messageID: string; id: string } }).part
d.staleDeltas.add(deltaKey(part.messageID, part.id, "text"))
d.staleDeltas.add(deltaKey(part.messageID, part.id, "output"))
}
}
syncDebug.pipeline.coalesced(normalizedPayload.type, k)
continue
}
d.coalesced.set(k, d.queue.length)
}
d.queue.push(normalizedPayload)
scheduleDir(routedDirectory)
if (Date.now() - yielded < STREAM_YIELD_MS) continue
yielded = Date.now()
await wait(0)
}
} catch (error) {
if (!isAbortError(error) && !streamErrorLogged) {
streamErrorLogged = true
console.error("[event-pipeline] stream failed", error)
}
} finally {
abort.signal.removeEventListener("abort", onAbort)
attempt = undefined
clearHeartbeat()
}
if (abort.signal.aborted) return
await wait(RECONNECT_DELAY_MS)
}
})().finally(flushAll)
// Visibility handler — abort SSE on heartbeat timeout so the loop reconnects.
// The reconnect triggers onReconnect above, which lets consumers resync state.
const onVisibility = () => {
if (typeof document === "undefined") return
if (document.visibilityState !== "visible") return
if (Date.now() - lastEventAt < HEARTBEAT_TIMEOUT_MS) return
attempt?.abort()
}
// pageshow handler — fires on back-forward cache restore (common on mobile PWA).
// bfcache restores the page without a fresh load, so SSE state may be stale.
const onPageShow = (event: PageTransitionEvent) => {
if (!event.persisted) return
attempt?.abort()
}
if (typeof document !== "undefined") {
document.addEventListener("visibilitychange", onVisibility)
window.addEventListener("pageshow", onPageShow)
}
// Cleanup — abort SSE, flush remaining events, remove listeners
const cleanup = () => {
if (typeof document !== "undefined") {
document.removeEventListener("visibilitychange", onVisibility)
window.removeEventListener("pageshow", onPageShow)
}
abort.abort()
flushAll()
}
return { cleanup }
}