zhongwei/gh-jezweb-claude-skills-skills-cloudflare-queues
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Initial commit

Browse Source
This commit is contained in:
Zhongwei Li
2025-11-30 08:24:26 +08:00
commit ce4251a69d
14 changed files with 3532 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

558
SKILL.md Normal file
View File

@@ -0,0 +1,558 @@
---
name: cloudflare-queues
description: |
Build async message queues with Cloudflare Queues for background processing. Use when: handling async tasks, batch processing, implementing retries, configuring dead letter queues, managing consumer concurrency, or troubleshooting queue timeout, batch retry, message loss, or throughput exceeded.
license: MIT
---
# Cloudflare Queues
**Status**: Production Ready ✅
**Last Updated**: 2025-11-24
**Dependencies**: cloudflare-worker-base (for Worker setup)
**Latest Versions**: wrangler@4.50.0, @cloudflare/workers-types@4.20251121.0
**Recent Updates (2025)**:
- **April 2025**: Pull consumers increased limits (5,000 msg/s per queue, up from 1,200 requests/5min)
- **March 2025**: Pause & Purge APIs (wrangler queues pause-delivery, queues purge)
- **2025**: Customizable retention (60s to 14 days, previously fixed at 4 days)
- **2025**: Increased queue limits (10,000 queues per account, up from 10)
---
## Quick Start (5 Minutes)
```bash
# 1. Create queue
npx wrangler queues create my-queue
# 2. Add producer binding to wrangler.jsonc
# { "queues": { "producers": [{ "binding": "MY_QUEUE", "queue": "my-queue" }] } }
# 3. Send message from Worker
await env.MY_QUEUE.send({ userId: '123', action: 'process-order' });
# 4. Add consumer binding to wrangler.jsonc
# { "queues": { "consumers": [{ "queue": "my-queue", "max_batch_size": 10 }] } }
# 5. Process messages
export default {
async queue(batch: MessageBatch, env: Env): Promise<void> {
for (const message of batch.messages) {
await processMessage(message.body);
message.ack(); // Explicit acknowledgement
}
}
};
# 6. Deploy and test
npx wrangler deploy
npx wrangler tail my-consumer
```
---
## Producer API
```typescript
// Send single message
await env.MY_QUEUE.send({ userId: '123', action: 'send-email' });
// Send with delay (max 12 hours)
await env.MY_QUEUE.send({ action: 'reminder' }, { delaySeconds: 600 });
// Send batch (max 100 messages or 256 KB)
await env.MY_QUEUE.sendBatch([
{ body: { userId: '1' } },
{ body: { userId: '2' } },
]);
```
**Critical Limits:**
- Message size: **128 KB max** (including ~100 bytes metadata)
- Messages >128 KB will fail - store in R2 and send reference instead
- Batch size: 100 messages or 256 KB total
- Delay: 0-43200 seconds (12 hours max)
---
## Consumer API
```typescript
export default {
async queue(batch: MessageBatch, env: Env, ctx: ExecutionContext): Promise<void> {
for (const message of batch.messages) {
// message.id - unique UUID
// message.timestamp - Date when sent
// message.body - your content
// message.attempts - retry count (starts at 1)
await processMessage(message.body);
message.ack(); // Explicit ack (critical for non-idempotent ops)
}
}
};
// Retry with exponential backoff
message.retry({ delaySeconds: Math.min(60 * Math.pow(2, message.attempts - 1), 3600) });
// Batch methods
batch.ackAll(); // Ack all messages
batch.retryAll(); // Retry all messages
```
**Critical:**
- **`message.ack()`** - Mark success, prevents retry even if handler fails later
- **Use explicit ack for non-idempotent operations** (DB writes, API calls, payments)
- **Implicit ack** - If handler returns successfully without calling ack(), all messages auto-acknowledged
- **Ordering not guaranteed** - Don't assume FIFO message order
---
## Critical Consumer Patterns
### Explicit Acknowledgement (Non-Idempotent Operations)
**ALWAYS use explicit ack() for:** Database writes, API calls, financial transactions
```typescript
export default {
async queue(batch: MessageBatch, env: Env): Promise<void> {
for (const message of batch.messages) {
try {
await env.DB.prepare('INSERT INTO orders (id, amount) VALUES (?, ?)')
.bind(message.body.orderId, message.body.amount).run();
message.ack(); // Only ack on success
} catch (error) {
console.error(`Failed ${message.id}:`, error);
// Don't ack - will retry
}
}
}
};
```
**Why?** Prevents duplicate writes if one message in batch fails. Failed messages retry independently.
---
### Exponential Backoff for Rate-Limited APIs
```typescript
export default {
async queue(batch: MessageBatch, env: Env): Promise<void> {
for (const message of batch.messages) {
try {
await fetch('https://api.example.com/process', {
method: 'POST',
body: JSON.stringify(message.body),
});
message.ack();
} catch (error) {
if (error.status === 429) {
const delaySeconds = Math.min(60 * Math.pow(2, message.attempts - 1), 3600);
message.retry({ delaySeconds });
} else {
message.retry();
}
}
}
}
};
```
---
### Dead Letter Queue (DLQ) - CRITICAL for Production
**⚠️ Without DLQ, failed messages are DELETED PERMANENTLY after max_retries**
```bash
npx wrangler queues create my-dlq
```
**wrangler.jsonc:**
```jsonc
{
"queues": {
"consumers": [{
"queue": "my-queue",
"max_retries": 3,
"dead_letter_queue": "my-dlq" // Messages go here after 3 failed retries
}]
}
}
```
**DLQ Consumer:**
```typescript
export default {
async queue(batch: MessageBatch, env: Env): Promise<void> {
for (const message of batch.messages) {
console.error('PERMANENTLY FAILED:', message.id, message.body);
await env.DB.prepare('INSERT INTO failed_messages (id, body) VALUES (?, ?)')
.bind(message.id, JSON.stringify(message.body)).run();
message.ack(); // Remove from DLQ
}
}
};
```
---
## Consumer Configuration
```jsonc
{
"queues": {
"consumers": [{
"queue": "my-queue",
"max_batch_size": 100, // 1-100 (default: 10)
"max_batch_timeout": 30, // 0-60s (default: 5s)
"max_retries": 5, // 0-100 (default: 3)
"retry_delay": 300, // Seconds (default: 0)
"max_concurrency": 10, // 1-250 (default: auto-scale)
"dead_letter_queue": "my-dlq" // REQUIRED for production
}]
}
}
```
**Critical Settings:**
- **Batching** - Consumer called when EITHER condition met (max_batch_size OR max_batch_timeout)
- **max_retries** - After exhausted: with DLQ → sent to DLQ, without DLQ → **DELETED PERMANENTLY**
- **max_concurrency** - Only set if upstream has rate limits or connection limits. Otherwise leave unset for auto-scaling (up to 250 concurrent invocations)
- **DLQ** - Create separately: `npx wrangler queues create my-dlq`
---
## Wrangler Commands
```bash
# Create queue
npx wrangler queues create my-queue
npx wrangler queues create my-queue --message-retention-period-secs 1209600 # 14 days
# Manage queues
npx wrangler queues list
npx wrangler queues info my-queue
npx wrangler queues delete my-queue # ⚠️ Deletes ALL messages!
# Pause/Purge (March 2025 - NEW)
npx wrangler queues pause-delivery my-queue # Pause processing, keep receiving
npx wrangler queues resume-delivery my-queue
npx wrangler queues purge my-queue # ⚠️ Permanently deletes all messages!
# Consumer management
npx wrangler queues consumer add my-queue my-consumer-worker \
--batch-size 50 --batch-timeout 10 --message-retries 5
npx wrangler queues consumer remove my-queue my-consumer-worker
```
---
## Limits & Quotas
| Feature | Limit |
|---------|-------|
| **Queues per account** | 10,000 |
| **Message size** | 128 KB (includes ~100 bytes metadata) |
| **Message retries** | 100 max |
| **Batch size** | 1-100 messages |
| **Batch timeout** | 0-60 seconds |
| **Messages per sendBatch** | 100 (or 256 KB total) |
| **Queue throughput** | 5,000 messages/second per queue |
| **Message retention** | 4 days (default), 14 days (max) |
| **Queue backlog size** | 25 GB per queue |
| **Concurrent consumers** | 250 (push-based, auto-scale) |
| **Consumer duration** | 15 minutes (wall clock) |
| **Consumer CPU time** | 30 seconds (default), 5 minutes (max) |
| **Visibility timeout** | 12 hours (pull consumers) |
| **Message delay** | 12 hours (max) |
| **API rate limit** | 1200 requests / 5 minutes |
---
## Pricing
**Requires Workers Paid plan** ($5/month)
**Operations Pricing:**
- First 1,000,000 operations/month: **FREE**
- After that: **$0.40 per million operations**
**What counts as an operation:**
- Each 64 KB chunk written, read, or deleted
- Messages >64 KB count as multiple operations:
- 65 KB message = 2 operations
- 127 KB message = 2 operations
- 128 KB message = 2 operations
**Typical message lifecycle:**
- 1 write + 1 read + 1 delete = **3 operations**
**Retries:**
- Each retry = additional **read operation**
- Message retried 3 times = 1 write + 4 reads + 1 delete = **6 operations**
**Dead Letter Queue:**
- Writing to DLQ = additional **write operation**
**Cost examples:**
- 1M messages/month (no retries): ((1M × 3) - 1M) / 1M × $0.40 = **$0.80**
- 10M messages/month: ((10M × 3) - 1M) / 1M × $0.40 = **$11.60**
- 100M messages/month: ((100M × 3) - 1M) / 1M × $0.40 = **$119.60**
---
## Error Handling
### Common Errors
#### 1. Message Too Large
```typescript
// ❌ Bad: Message >128 KB
await env.MY_QUEUE.send({
data: largeArray, // >128 KB
});
// ✅ Good: Check size before sending
const message = { data: largeArray };
const size = new TextEncoder().encode(JSON.stringify(message)).length;
if (size > 128000) {
// Store in R2, send reference
const key = `messages/${crypto.randomUUID()}.json`;
await env.MY_BUCKET.put(key, JSON.stringify(message));
await env.MY_QUEUE.send({ type: 'large-message', r2Key: key });
} else {
await env.MY_QUEUE.send(message);
}
```
---
#### 2. Throughput Exceeded
```typescript
// ❌ Bad: Exceeding 5000 msg/s per queue
for (let i = 0; i < 10000; i++) {
await env.MY_QUEUE.send({ id: i }); // Too fast!
}
// ✅ Good: Use sendBatch
const messages = Array.from({ length: 10000 }, (_, i) => ({
body: { id: i },
}));
// Send in batches of 100
for (let i = 0; i < messages.length; i += 100) {
await env.MY_QUEUE.sendBatch(messages.slice(i, i + 100));
}
// ✅ Even better: Rate limit with delay
for (let i = 0; i < messages.length; i += 100) {
await env.MY_QUEUE.sendBatch(messages.slice(i, i + 100));
if (i + 100 < messages.length) {
await new Promise(resolve => setTimeout(resolve, 100)); // 100ms delay
}
}
```
---
#### 3. Consumer Timeout
```typescript
// ❌ Bad: Long processing without CPU limit increase
export default {
async queue(batch: MessageBatch): Promise<void> {
for (const message of batch.messages) {
await processForMinutes(message.body); // CPU timeout!
}
},
};
// ✅ Good: Increase CPU limit in wrangler.jsonc
```
**wrangler.jsonc:**
```jsonc
{
"limits": {
"cpu_ms": 300000 // 5 minutes (max allowed)
}
}
```
---
#### 4. Backlog Growing
```typescript
// Issue: Consumer too slow, backlog growing
// ✅ Solution 1: Increase batch size
{
"queues": {
"consumers": [{
"queue": "my-queue",
"max_batch_size": 100 // Process more per invocation
}]
}
}
// ✅ Solution 2: Let concurrency auto-scale (don't set max_concurrency)
// ✅ Solution 3: Optimize consumer code
export default {
async queue(batch: MessageBatch, env: Env): Promise<void> {
// Process in parallel
await Promise.all(
batch.messages.map(async (message) => {
await process(message.body);
message.ack();
})
);
},
};
```
---
## Critical Rules
**Always:**
- ✅ Configure DLQ for production (`dead_letter_queue` in consumer config)
- ✅ Use explicit `message.ack()` for non-idempotent ops (DB writes, API calls)
- ✅ Validate message size <128 KB before sending
- ✅ Use `sendBatch()` for multiple messages (more efficient)
- ✅ Implement exponential backoff: `60 * Math.pow(2, message.attempts - 1)`
- ✅ Let concurrency auto-scale (don't set `max_concurrency` unless upstream has rate limits)
**Never:**
- ❌ Never assume FIFO ordering - not guaranteed
- ❌ Never rely on implicit ack for non-idempotent ops - use explicit `ack()`
- ❌ Never send messages >128 KB - will fail (store in R2 instead)
- ❌ Never skip DLQ in production - failed messages DELETED PERMANENTLY without DLQ
- ❌ Never exceed 5,000 msg/s per queue (push consumers) or rate limits apply
- ❌ Never process messages synchronously - use `Promise.all()` for parallelism
---
## Troubleshooting
### Issue: Messages not being delivered to consumer
**Possible causes:**
1. Consumer not deployed
2. Wrong queue name in wrangler.jsonc
3. Delivery paused
4. Consumer throwing errors
**Solution:**
```bash
# Check queue info
npx wrangler queues info my-queue
# Check if delivery paused
npx wrangler queues resume-delivery my-queue
# Check consumer logs
npx wrangler tail my-consumer
```
---
### Issue: Entire batch retried when one message fails
**Cause:** Using implicit acknowledgement with non-idempotent operations
**Solution:** Use explicit ack()
```typescript
// ✅ Explicit ack
for (const message of batch.messages) {
try {
await dbWrite(message.body);
message.ack(); // Only ack on success
} catch (error) {
console.error(`Failed: ${message.id}`);
// Don't ack - will retry
}
}
```
---
### Issue: Messages deleted without processing
**Cause:** No Dead Letter Queue configured
**Solution:**
```bash
# Create DLQ
npx wrangler queues create my-dlq
# Add to consumer config
```
```jsonc
{
"queues": {
"consumers": [{
"queue": "my-queue",
"dead_letter_queue": "my-dlq"
}]
}
}
```
---
### Issue: Consumer not auto-scaling
**Possible causes:**
1. `max_concurrency` set to 1
2. Consumer returning errors (not processing)
3. Batch processing too fast (no backlog)
**Solution:**
```jsonc
{
"queues": {
"consumers": [{
"queue": "my-queue",
// Don't set max_concurrency - let it auto-scale
"max_batch_size": 50 // Increase batch size instead
}]
}
}
```
---
## Related Documentation
- [Cloudflare Queues Docs](https://developers.cloudflare.com/queues/)
- [How Queues Works](https://developers.cloudflare.com/queues/reference/how-queues-works/)
- [JavaScript APIs](https://developers.cloudflare.com/queues/configuration/javascript-apis/)
- [Batching & Retries](https://developers.cloudflare.com/queues/configuration/batching-retries/)
- [Consumer Concurrency](https://developers.cloudflare.com/queues/configuration/consumer-concurrency/)
- [Dead Letter Queues](https://developers.cloudflare.com/queues/configuration/dead-letter-queues/)
- [Wrangler Commands](https://developers.cloudflare.com/queues/reference/wrangler-commands/)
- [Limits](https://developers.cloudflare.com/queues/platform/limits/)
- [Pricing](https://developers.cloudflare.com/queues/platform/pricing/)
---
**Last Updated**: 2025-10-21
**Version**: 1.0.0
**Maintainer**: Jeremy Dawes | jeremy@jezweb.net