40 lines
1.6 KiB
TypeScript
40 lines
1.6 KiB
TypeScript
function conflict(message: string): Error & { statusCode: number } {
|
|
return Object.assign(new Error(message), { statusCode: 409 })
|
|
}
|
|
|
|
/** Handler lifetime, not socket lifetime: disconnect does not finish an active write. */
|
|
export class DatabaseRequestGate {
|
|
private paused = false
|
|
private active = new Map<symbol, (() => void) | undefined>()
|
|
private idle: (() => void) | undefined
|
|
|
|
async request<T>(run: () => Promise<T>, cancelStream?: () => void): Promise<T> {
|
|
if (this.paused) throw conflict("Выполняется операция с базой приложения; повторите запрос позже")
|
|
const lease = Symbol()
|
|
this.active.set(lease, cancelStream)
|
|
try { return await run() }
|
|
finally {
|
|
this.active.delete(lease)
|
|
if (!this.active.size) this.idle?.()
|
|
}
|
|
}
|
|
|
|
async exclusive<T>(run: () => Promise<T>, timeoutMs = 30_000): Promise<T> {
|
|
if (this.paused) throw conflict("Операция с базой приложения уже выполняется")
|
|
this.paused = true
|
|
let timer: ReturnType<typeof setTimeout> | undefined
|
|
try {
|
|
for (const cancel of this.active.values()) cancel?.()
|
|
if (this.active.size) await new Promise<void>((resolve, reject) => {
|
|
this.idle = resolve
|
|
timer = setTimeout(() => reject(conflict("Не удалось дождаться завершения API-запросов; операция с базой отменена")), timeoutMs)
|
|
})
|
|
return await run()
|
|
} finally {
|
|
if (timer) clearTimeout(timer)
|
|
this.idle = undefined
|
|
this.paused = false
|
|
}
|
|
}
|
|
}
|