missing queue_max_length metric (policy limits)

[devops-verci]

hello
iam using this config:
{ "rabbit_url": "http://127.0.0.1:15672", "rabbit_user": "exporter", "rabbit_pass": "exporter", "publish_port": "9419", "publish_addr": "", "output_format": "TTY", "insecure_skip_verify": true, "exlude_metrics": [], "include_queues": ".*", "skip_queues": "^$", "skip_vhost": "^$", "include_vhost": ".*", "rabbit_capabilities": "no_sort,bert", "enabled_exporters": [ "exchange", "node", "overview", "queue", "cluster" ], "timeout": 30, "max_queues": 0 }
and there is no queue_max_length metric.. why is that?
thank you

[kbudde]

HI @devops-verci,

The configuration looks ok. I suspect you have all the other queue metrics (like queue_message_bytes)?
You also have to apply the a policy to the queue (https://www.rabbitmq.com/maxlength.html).

You should see the limits inside rabbitmq management interface per queue. If the limits are visible there, they should be included in the metrics.

You can check the api yourself (rabbit/api/queues). There you should find x-max-length setting.

  {
    "arguments": {
      "x-max-length": 123,
      "x-max-length-bytes": 1024,
      "x-queue-type": "classic"
    },
    "auto_delete": false,
    "backing_queue_status": {
      "avg_ack_egress_rate": 0,
      "avg_ack_ingress_rate": 0,
      "avg_egress_rate": 0,
      "avg_ingress_rate": 0,
      "delta": [
        "delta",
        "undefined",
        0,
        0,
        "undefined"
      ],
      "len": 0,
      "mode": "default",
      "next_seq_id": 0,
      "q1": 0,
      "q2": 0,
      "q3": 0,
      "q4": 0,
      "target_ram_count": "infinity"
    },
    "consumer_capacity": 0,
    "consumer_utilisation": 0,
    "consumers": 0,
    "durable": true,
    "effective_policy_definition": {},
    "exclusive": false,
    "exclusive_consumer_tag": null,
    "garbage_collection": {
      "fullsweep_after": 65535,
      "max_heap_size": 0,
      "min_bin_vheap_size": 46422,
      "min_heap_size": 233,
      "minor_gcs": 1
    },
    "head_message_timestamp": null,
    "idle_since": "2021-12-11 18:00:28",
    "memory": 13952,
    "message_bytes": 0,
    "message_bytes_paged_out": 0,
    "message_bytes_persistent": 0,
    "message_bytes_ram": 0,
    "message_bytes_ready": 0,
    "message_bytes_unacknowledged": 0,
    "messages": 0,
    "messages_details": {
      "rate": 0
    },
    "messages_paged_out": 0,
    "messages_persistent": 0,
    "messages_ram": 0,
    "messages_ready": 0,
    "messages_ready_details": {
      "rate": 0
    },
    "messages_ready_ram": 0,
    "messages_unacknowledged": 0,
    "messages_unacknowledged_details": {
      "rate": 0
    },
    "messages_unacknowledged_ram": 0,
    "name": "test_with_limits",
    "node": "rabbit@9d7a086adb9d",
    "operator_policy": null,
    "policy": null,
    "recoverable_slaves": null,
    "reductions": 5901,
    "reductions_details": {
      "rate": 0
    },
    "single_active_consumer_tag": null,
    "state": "running",
    "type": "classic",
    "vhost": "/"
  },
  {
    "arguments": {
      "x-queue-type": "classic"
    },
    "auto_delete": false,
    "backing_queue_status": {
      "avg_ack_egress_rate": 0,
      "avg_ack_ingress_rate": 0,
      "avg_egress_rate": 0,
      "avg_ingress_rate": 0,
      "delta": [
        "delta",
        "undefined",
        0,
        0,
        "undefined"
      ],
      "len": 0,
      "mode": "default",
      "next_seq_id": 0,
      "q1": 0,
      "q2": 0,
      "q3": 0,
      "q4": 0,
      "target_ram_count": "infinity"
    },
    "consumer_capacity": 0,
    "consumer_utilisation": 0,
    "consumers": 0,
    "durable": true,
    "effective_policy_definition": {},
    "exclusive": false,
    "exclusive_consumer_tag": null,
    "garbage_collection": {
      "fullsweep_after": 65535,
      "max_heap_size": 0,
      "min_bin_vheap_size": 46422,
      "min_heap_size": 233,
      "minor_gcs": 7
    },
    "head_message_timestamp": null,
    "idle_since": "2021-12-11 18:00:03",
    "memory": 13792,
    "message_bytes": 0,
    "message_bytes_paged_out": 0,
    "message_bytes_persistent": 0,
    "message_bytes_ram": 0,
    "message_bytes_ready": 0,
    "message_bytes_unacknowledged": 0,
    "messages": 0,
    "messages_details": {
      "rate": 0
    },
    "messages_paged_out": 0,
    "messages_persistent": 0,
    "messages_ram": 0,
    "messages_ready": 0,
    "messages_ready_details": {
      "rate": 0
    },
    "messages_ready_ram": 0,
    "messages_unacknowledged": 0,
    "messages_unacknowledged_details": {
      "rate": 0
    },
    "messages_unacknowledged_ram": 0,
    "name": "test_without_policy",
    "node": "rabbit@9d7a086adb9d",
    "operator_policy": null,
    "policy": null,
    "recoverable_slaves": null,
    "reductions": 5666,
    "reductions_details": {
      "rate": 0
    },
    "single_active_consumer_tag": null,
    "state": "running",
    "type": "classic",
    "vhost": "/"
  }
]```

[devops-verci]

ive checked our rabbitmq, it looks like this:

  "consumer_capacity": 0,
  "consumer_utilisation": 0,
  "consumers": 0,
  "deliveries": [],
  "durable": true,
  "effective_policy_definition": {
    "max-length": 20000
  },
  "exclusive": false,

so we have max-length, but format not same as yours...

[kbudde]

Interesting. Which rabbitMQ version is it?

[devops-verci]

rabbitmq_build_info{erlang_version="24.0.5", instance=":15692", job="rabbitMQ", 
prometheus_client_version="4.8.1", prometheus_plugin_version="3.9.5", rabbitmq_version="3.9.5"}

[kbudde]

@devops-verci Thank you for the information.
The problem is much simpler: At the moment this exporter only exports the limits if they are supplied as arguments while creating the queue. Limits assigned through policies are not processed at all.
I will create an improved version the next days which will expose the effective limit (if a limit is set on queue creation and through policy, the lower limit is applied).

[kbudde]

Hi,

@devops-verci can you please verify the latest version. It should provide the limits you are looking for.

[devops-verci]

thank you so much, metrics appeared.