Handling Flow Control

memory_scavenge_threshold: 0.8
disk_free_limit.absolute: 50MB

disk_free_limit.absolute = 50MB
disk_free_limit.relative = 0.1

vm_memory_high_watermark: 0.6
vm_memory_high_watermark.absolute: 2147483648

disk_free_limit:
  relative: 1.5

const amqp = require('amqplib');

async function handleBlockedConnections() {
  const connection = await amqp.connect('amqp://localhost');
  const channel = await connection.createChannel();

  // Set up a listener for blocked events
  connection.on('blocked', (reason) => {
    console.log('Connection blocked:', reason);
    // Implement backoff or retry logic here
  });

  // Set up a listener for unblocked events
  connection.on('unblocked', () => {
    console.log('Connection unblocked');
    // Resume normal operations
  });

  // Example: Publishing a message that might trigger blocking
  try {
    await channel.publish('', 'queue_name', Buffer.from('message'));
  } catch (err) {
    console.error('Publish failed:', err);
  }
}

handleBlockedConnections().catch(console.error);

rabbitmqctl status

{
  "rabbit": {
    "flow": {
      "enabled": true,
      "recovery": {
        "strategy": "pause",
        "timeout": 30000
      }
    }
  }
}

vm_memory_limit: 1073741824
disk_free_limit: 52428800
max_paged_messages: 2000000

const queueOptions = {
  durable: true,
  arguments: {
    'x-max-length': 1000,
    'x-overflow': 'reject-publish'
  }
};

await channel.assertQueue('my-queue', queueOptions);

rabbitmqctl set_vm_memory_high_watermark 0.4
rabbitmqctl set_vm_memory_high_watermark_paging_ratio 0.8

const amqp = require('amqplib');

async function handleFlowControl() {
  const connection = await amqp.connect('amqp://localhost');
  const channel = await connection.createChannel();

  channel.on('flow', (active) => {
    if (active) {
      console.log('Flow control activated - pausing publishing');
    } else {
      console.log('Flow control deactivated - resuming publishing');
    }
  });

  // Publishing logic here...
}

# Set memory limit to 2GB
vm_memory_limit = 2147483648

# Set high watermark to 50% of total system memory
vm_memory_high_watermark = 0.5

# Set persistent message watermark to 60%
vm_memory_high_watermark_persistent = 0.6

const amqp = require('amqplib');

async function handleProducerBackpressure() {
  const connection = await amqp.connect('amqp://localhost');
  const channel = await connection.createChannel();

  // Set up flow control monitoring
  channel.flow(true); // Enable flow control

  // Handle backpressure events
  channel.on('flow', (active) => {
    if (active) {
      console.log('Flow control activated - pausing message production');
    } else {
      console.log('Flow control deactivated - resuming message production');
    }
  });

  // Produce messages with flow control awareness
  for (let i = 0; i < 1000; i++) {
    const message = { id: i, data: `Message ${i}` };
    const success = channel.publish('exchange', 'routing.key', Buffer.from(JSON.stringify(message)));

    if (!success) {
      console.log('Message not published due to flow control');
      // Implement retry logic or queue management here
    }
  }

  await channel.close();
  await connection.close();
}

handleProducerBackpressure().catch(console.error);