Request to Expose fluentd_buffer_queue_length Metric in fluent-plugin-prometheus

[vp2312]

We are currently using fluent-plugin-prometheus to monitor Fluentd buffer metrics and optimize log processing performance. The plugin already exposes several key buffer-related metrics.
However, we have identified the need for an additional metric: fluentd_buffer_queue_length (distinct from fluentd_output_status_buffer_queue_length).

Reason for Request:
We are analyzing Fluentd’s queuing behavior to fine-tune queued_chunks_limit_size for optimal performance.
Having both input and output buffer queue length metrics would help in diagnosing potential bottlenecks and understanding buffer pressure.
This metric would enable more precise monitoring and alerting based on Fluentd’s internal queuing dynamics.

Request:
Please consider adding fluentd_buffer_queue_length as an exposed metric in fluent-plugin-prometheus. This will help us and other users better monitor and optimize Fluentd performance.

Thank you for your support and for maintaining this valuable plugin!