Using Python Pika to get queue counts
matt.s...@fanmanager.com
Below is a bit of code that I found somewhere on how to query Rabbit using Python to get the queue message count. I have a process that uses this and tries to determine when the queues are clear, then it powers off the servers (only runs on dev servers). Before this runs, the process that adds new messages is shut off, we've verified no new messages are being added. The problem I'm having is it "seems" to be getting the correct message count, but I've had a complaint that a few times the server was shutdown with a possible unack'd message.
Does message_count show *all* messages, or only ready messages?
servername = "mq001"
params = pika.ConnectionParameters(
host=servername,
port=port,
virtual_host=virtual_host,
credentials=pika.PlainCredentials(username,password),
)
connection = pika.BlockingConnection(params)
channel = connection.channel()
status = channel.queue_declare(queue=queue_name, durable=True)
count = status.method.message_count
Michael Klishin
> Does message_count show *all* messages, or only ready messages?
The reason for this is simple: a client that gets the count might then choose to
consume exactly that number of messages, or pre-allocate resources, etc.
If there is a huge number of unacknowledged messages, we don't want them to assume
there's more than they really can consume.
Use HTTP API to get the breakdown you see in the management UI (ready/unacked/total).
--
MK
Staff Software Engineer, Pivotal/RabbitMQ
Matt Shields
Michael Klishin
> Is there a way to programmatically get it, either via Pika or
> another Python library?
say, Requests.
See
https://raw.githack.com/rabbitmq/rabbitmq-management/rabbitmq_v3_6_0/priv/www/api/index.html
which is available at /api on any management plugin instance.
If you need an example of such client, take a look at https://github.com/ruby-amqp/rabbitmq_http_api_client, it's
the closest thing I know of to Python. There are also Java and Go clients.
Back to your original question, you want GET /api/queues/{vhost}/{name}.