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import assert from "node:assert";
import { and, asc, count, eq, gt, lt, or } from "drizzle-orm";
import { buildDBClient } from "./db";
import { SqliteQueueOptions } from "./options";
import { Job, tasksTable } from "./schema";
// generate random id
function generateAllocationId() {
return Math.random().toString(36).substring(2, 15);
}
export class SqliteQueue<T> {
queueName: string;
db: ReturnType<typeof buildDBClient>;
options: SqliteQueueOptions;
constructor(
name: string,
db: ReturnType<typeof buildDBClient>,
options: SqliteQueueOptions,
) {
this.queueName = name;
this.options = options;
this.db = db;
}
name() {
return this.queueName;
}
async enqueue(payload: T): Promise<Job> {
const job = await this.db
.insert(tasksTable)
.values({
queue: this.queueName,
payload: JSON.stringify(payload),
numRunsLeft: this.options.defaultJobArgs.numRetries + 1,
maxNumRuns: this.options.defaultJobArgs.numRetries + 1,
allocationId: generateAllocationId(),
})
.returning();
return job[0];
}
async stats() {
const res = await this.db
.select({ status: tasksTable.status, count: count() })
.from(tasksTable)
.where(eq(tasksTable.queue, this.queueName))
.groupBy(tasksTable.status);
return res.reduce(
(acc, r) => {
acc[r.status] += r.count;
return acc;
},
{
pending: 0,
pending_retry: 0,
running: 0,
failed: 0,
},
);
}
async attemptDequeue(options: { timeoutSecs: number }): Promise<Job | null> {
return await this.db.transaction(async (txn) => {
const jobs = await txn
.select()
.from(tasksTable)
.where(
and(
eq(tasksTable.queue, this.queueName),
gt(tasksTable.numRunsLeft, 0),
or(
// Not picked by a worker yet
eq(tasksTable.status, "pending"),
// Failed but still has attempts left
eq(tasksTable.status, "pending_retry"),
// Expired and still has attempts left
and(
eq(tasksTable.status, "running"),
lt(tasksTable.expireAt, new Date()),
),
),
),
)
.orderBy(asc(tasksTable.createdAt))
.limit(1);
if (jobs.length == 0) {
return null;
}
assert(jobs.length == 1);
const job = jobs[0];
const result = await txn
.update(tasksTable)
.set({
status: "running",
numRunsLeft: job.numRunsLeft - 1,
allocationId: generateAllocationId(),
expireAt: new Date(new Date().getTime() + options.timeoutSecs * 1000),
})
.where(
and(
eq(tasksTable.id, job.id),
// The compare and swap is necessary to avoid race conditions
eq(tasksTable.allocationId, job.allocationId),
),
)
.returning();
if (result.length == 0) {
return null;
}
assert(result.length == 1);
return result[0];
});
}
async finalize(
id: number,
alloctionId: string,
status: "completed" | "pending_retry" | "failed",
) {
if (status == "completed") {
await this.db
.delete(tasksTable)
.where(
and(eq(tasksTable.id, id), eq(tasksTable.allocationId, alloctionId)),
);
} else {
await this.db
.update(tasksTable)
.set({ status: status, expireAt: null })
.where(
and(eq(tasksTable.id, id), eq(tasksTable.allocationId, alloctionId)),
);
}
}
}
|
