signal-desktop/ts/jobs/JobQueueDatabaseStore.ts
2021-04-29 18:02:27 -05:00

107 lines
3.1 KiB
TypeScript

// Copyright 2021 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
import { pick, noop } from 'lodash';
import { AsyncQueue } from '../util/AsyncQueue';
import { concat, wrapPromise } from '../util/asyncIterables';
import { JobQueueStore, StoredJob } from './types';
import databaseInterface from '../sql/Client';
import * as log from '../logging/log';
type Database = {
getJobsInQueue(queueType: string): Promise<Array<StoredJob>>;
insertJob(job: Readonly<StoredJob>): Promise<void>;
deleteJob(id: string): Promise<void>;
};
export class JobQueueDatabaseStore implements JobQueueStore {
private activeQueueTypes = new Set<string>();
private queues = new Map<string, AsyncQueue<StoredJob>>();
private initialFetchPromises = new Map<string, Promise<void>>();
constructor(private readonly db: Database) {}
async insert(job: Readonly<StoredJob>): Promise<void> {
log.info(
`JobQueueDatabaseStore adding job ${job.id} to queue ${JSON.stringify(
job.queueType
)}`
);
const initialFetchPromise = this.initialFetchPromises.get(job.queueType);
if (!initialFetchPromise) {
throw new Error(
`JobQueueDatabaseStore tried to add job for queue ${JSON.stringify(
job.queueType
)} but streaming had not yet started`
);
}
await initialFetchPromise;
await this.db.insertJob(
pick(job, ['id', 'timestamp', 'queueType', 'data'])
);
this.getQueue(job.queueType).add(job);
}
async delete(id: string): Promise<void> {
await this.db.deleteJob(id);
}
stream(queueType: string): AsyncIterable<StoredJob> {
if (this.activeQueueTypes.has(queueType)) {
throw new Error(
`Cannot stream queue type ${JSON.stringify(queueType)} more than once`
);
}
this.activeQueueTypes.add(queueType);
return concat([
wrapPromise(this.fetchJobsAtStart(queueType)),
this.getQueue(queueType),
]);
}
private getQueue(queueType: string): AsyncQueue<StoredJob> {
const existingQueue = this.queues.get(queueType);
if (existingQueue) {
return existingQueue;
}
const result = new AsyncQueue<StoredJob>();
this.queues.set(queueType, result);
return result;
}
private async fetchJobsAtStart(queueType: string): Promise<Array<StoredJob>> {
log.info(
`JobQueueDatabaseStore fetching existing jobs for queue ${JSON.stringify(
queueType
)}`
);
// This is initialized to `noop` because TypeScript doesn't know that `Promise` calls
// its callback synchronously, making sure `onFinished` is defined.
let onFinished: () => void = noop;
const initialFetchPromise = new Promise<void>(resolve => {
onFinished = resolve;
});
this.initialFetchPromises.set(queueType, initialFetchPromise);
const result = await this.db.getJobsInQueue(queueType);
log.info(
`JobQueueDatabaseStore finished fetching existing ${
result.length
} jobs for queue ${JSON.stringify(queueType)}`
);
onFinished();
return result;
}
}
export const jobQueueDatabaseStore = new JobQueueDatabaseStore(
databaseInterface
);