Find SQS Queues Without a Dead-Letter Queue

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "ListQueues",
      "Effect": "Allow",
      "Action": "sqs:ListQueues",
      "Resource": "*"
    },
    {
      "Sid": "ReadQueueAttributes",
      "Effect": "Allow",
      "Action": "sqs:GetQueueAttributes",
      "Resource": "arn:aws:sqs:us-east-1:123456789012:*"
    }
  ]
}

// find-sqs-queues-without-dlq.ts
// Lists every SQS queue in one Region and reports which ones have no dead-letter queue,
// which redrive policies point at a queue that no longer exists, how deep each DLQ is,
// and DLQs whose retention is shorter than their source queue's. Report only.
// Usage: npx tsx find-sqs-queues-without-dlq.ts [--prefix orders] [--fail]
import { SQSClient, GetQueueAttributesCommand, paginateListQueues } from "@aws-sdk/client-sqs";

const args = process.argv.slice(2);
const prefixIdx = args.indexOf("--prefix");
const prefix = prefixIdx >= 0 ? args[prefixIdx + 1] : undefined;
const failOnFindings = args.includes("--fail"); // exit 1 for CI when a source queue has no DLQ
const sqs = new SQSClient({}); // region from AWS_REGION or your profile

interface Queue {
  name: string;
  arn: string;
  fifo: boolean;
  depth: number;
  retentionSec: number;
  dlqArn?: string;
  maxReceiveCount?: number;
}

async function loadQueues(): Promise<Queue[]> {
  const queues: Queue[] = [];
  // MaxResults (pageSize) must be set, or ListQueues returns at most 1,000 URLs and no NextToken.
  for await (const page of paginateListQueues({ client: sqs, pageSize: 1000 }, { QueueNamePrefix: prefix })) {
    for (const url of page.QueueUrls ?? []) {
      const { Attributes: a = {} } = await sqs.send(new GetQueueAttributesCommand({
        QueueUrl: url,
        AttributeNames: ["QueueArn", "FifoQueue", "ApproximateNumberOfMessages", "MessageRetentionPeriod", "RedrivePolicy"],
      }));
      const redrive = a.RedrivePolicy ? (JSON.parse(a.RedrivePolicy) as { deadLetterTargetArn?: string; maxReceiveCount?: number | string }) : undefined;
      queues.push({
        name: url.split("/").pop() ?? url,
        arn: a.QueueArn ?? "",
        fifo: a.FifoQueue === "true",
        depth: Number(a.ApproximateNumberOfMessages ?? 0),
        retentionSec: Number(a.MessageRetentionPeriod ?? 0),
        dlqArn: redrive?.deadLetterTargetArn,
        maxReceiveCount: redrive?.maxReceiveCount === undefined ? undefined : Number(redrive.maxReceiveCount),
      });
    }
  }
  return queues;
}

async function main(): Promise<void> {
  const queues = await loadQueues();
  const byArn = new Map(queues.map((q) => [q.arn, q]));
  const dlqArns = new Set(queues.flatMap((q) => (q.dlqArn ? [q.dlqArn] : [])));
  const days = (sec: number) => Math.round(sec / 86_400 * 10) / 10;

  const rows = queues.map((q) => {
    const row = { Queue: q.name, Type: q.fifo ? "FIFO" : "standard", Role: "source", DLQ: "-", MaxReceive: "-", Depth: q.depth, Finding: "ok" };
    if (dlqArns.has(q.arn)) {
      const sources = queues.filter((s) => s.dlqArn === q.arn);
      const shortest = sources.find((s) => !q.fifo && q.retentionSec <= s.retentionSec);
      row.Role = `DLQ for ${sources.length}`;
      if (q.depth > 0) row.Finding = `${q.depth} failed messages waiting`;
      else if (shortest) row.Finding = `retention ${days(q.retentionSec)}d not longer than ${shortest.name} (${days(shortest.retentionSec)}d)`;
      return row;
    }
    if (!q.dlqArn) {
      row.Finding = "NO DLQ";
      return row;
    }
    const target = byArn.get(q.dlqArn);
    row.DLQ = q.dlqArn.split(":").pop() ?? q.dlqArn;
    row.MaxReceive = String(q.maxReceiveCount ?? "-");
    if (!target && !prefix) row.Finding = "DLQ target does not exist";
    else if (q.maxReceiveCount === 1) row.Finding = "maxReceiveCount 1: one failed receive moves the message";
    return row;
  });

  rows.sort((a, b) => Number(b.Finding !== "ok") - Number(a.Finding !== "ok") || a.Queue.localeCompare(b.Queue));
  console.table(rows);
  const missing = rows.filter((r) => r.Finding === "NO DLQ").length;
  const usedDlqs = [...dlqArns].filter((arn) => byArn.has(arn)).length;
  console.log(`${queues.length} queues, ${usedDlqs} used as DLQs, ${missing} source queues without a DLQ.`);
  console.log("Report only: no queue attributes were changed.");
  if (failOnFindings && missing > 0) process.exit(1);
}

main().catch((err) => {
  console.error(err);
  process.exit(1);
});

npm install @aws-sdk/client-sqs
npm install --save-dev tsx typescript

# Every queue in the Region
AWS_PROFILE=readonly AWS_REGION=us-east-1 npx tsx find-sqs-queues-without-dlq.ts

# In CI: fail the job when any source queue has no DLQ
AWS_REGION=us-east-1 npx tsx find-sqs-queues-without-dlq.ts --fail

┌─────────┬────────────────────┬────────────┬─────────────┬────────────────────┬────────────┬───────┬───────────────────────────────────────────────────────────┐
│ (index) │ Queue              │ Type       │ Role        │ DLQ                │ MaxReceive │ Depth │ Finding                                                   │
├─────────┼────────────────────┼────────────┼─────────────┼────────────────────┼────────────┼───────┼───────────────────────────────────────────────────────────┤
│ 0       │ 'billing-events'   │ 'standard' │ 'source'    │ '-'                │ '-'        │ 0     │ 'NO DLQ'                                                  │
│ 1       │ 'email-outbox'     │ 'standard' │ 'source'    │ 'email-outbox-dlq' │ '1'        │ 3     │ 'maxReceiveCount 1: one failed receive moves the message' │
│ 2       │ 'orders-dlq'       │ 'standard' │ 'DLQ for 1' │ '-'                │ '-'        │ 42    │ '42 failed messages waiting'                              │
│ 3       │ 'payments.fifo'    │ 'FIFO'     │ 'source'    │ '-'                │ '-'        │ 0     │ 'NO DLQ'                                                  │
│ 4       │ 'search-index'     │ 'standard' │ 'source'    │ 'search-index-dlq' │ '5'        │ 0     │ 'DLQ target does not exist'                               │
│ 5       │ 'thumbnails-dlq'   │ 'standard' │ 'DLQ for 1' │ '-'                │ '-'        │ 0     │ 'retention 4d not longer than thumbnails (4d)'            │
│ 6       │ 'email-outbox-dlq' │ 'standard' │ 'DLQ for 1' │ '-'                │ '-'        │ 0     │ 'ok'                                                      │
│ 7       │ 'orders'           │ 'standard' │ 'source'    │ 'orders-dlq'       │ '5'        │ 118   │ 'ok'                                                      │
│ 8       │ 'thumbnails'       │ 'standard' │ 'source'    │ 'thumbnails-dlq'   │ '10'       │ 7     │ 'ok'                                                      │
└─────────┴────────────────────┴────────────┴─────────────┴────────────────────┴────────────┴───────┴───────────────────────────────────────────────────────────┘
9 queues, 3 used as DLQs, 2 source queues without a DLQ.
Report only: no queue attributes were changed.