prometheus: Add a metrics family for Khepri's Ra counters

[the-mikedavis]

This exposes all of the metrics that Ra collects in counters for the node's Khepri server under a new metric family in the "detailed" registry.

Example output...

$ curl -s "localhost:15692/metrics/detailed?family=khepri"
# TYPE rabbitmq_detailed_khepri_reserved_2 counter
# HELP rabbitmq_detailed_khepri_reserved_2 Reserved counter
rabbitmq_detailed_khepri_reserved_2 0
# TYPE rabbitmq_detailed_khepri_aux_commands counter
# HELP rabbitmq_detailed_khepri_aux_commands Total number of aux commands received
rabbitmq_detailed_khepri_aux_commands 0
# TYPE rabbitmq_detailed_khepri_checkpoints_promoted counter
# HELP rabbitmq_detailed_khepri_checkpoints_promoted Number of checkpoints promoted to snapshots
rabbitmq_detailed_khepri_checkpoints_promoted 0
# TYPE rabbitmq_detailed_khepri_command_flushes counter
# HELP rabbitmq_detailed_khepri_command_flushes Total number of low priority command batches written
rabbitmq_detailed_khepri_command_flushes 1
# TYPE rabbitmq_detailed_khepri_write_resends counter
# HELP rabbitmq_detailed_khepri_write_resends Total number of write resends
rabbitmq_detailed_khepri_write_resends 0
# TYPE rabbitmq_detailed_khepri_effective_machine_version gauge
# HELP rabbitmq_detailed_khepri_effective_machine_version The current effective version number of the machine.
rabbitmq_detailed_khepri_effective_machine_version 1
# TYPE rabbitmq_detailed_khepri_checkpoints counter
# HELP rabbitmq_detailed_khepri_checkpoints The number of checkpoint effects executed
rabbitmq_detailed_khepri_checkpoints 0
# TYPE rabbitmq_detailed_khepri_read_segment counter
# HELP rabbitmq_detailed_khepri_read_segment Total number of read segments
rabbitmq_detailed_khepri_read_segment 107
# TYPE rabbitmq_detailed_khepri_local_queries counter
# HELP rabbitmq_detailed_khepri_local_queries Total number of local queries
rabbitmq_detailed_khepri_local_queries 22
# TYPE rabbitmq_detailed_khepri_read_open_mem_tbl counter
# HELP rabbitmq_detailed_khepri_read_open_mem_tbl Total number of opened memory tables
rabbitmq_detailed_khepri_read_open_mem_tbl 0
# TYPE rabbitmq_detailed_khepri_rpcs_sent counter
# HELP rabbitmq_detailed_khepri_rpcs_sent Total number of rpcs, incl append_entries_rpcs
rabbitmq_detailed_khepri_rpcs_sent 0
# TYPE rabbitmq_detailed_khepri_dropped_sends counter
# HELP rabbitmq_detailed_khepri_dropped_sends Total number of message sends that return noconnect or nosuspend are dropped
rabbitmq_detailed_khepri_dropped_sends 0
# TYPE rabbitmq_detailed_khepri_forced_gcs counter
# HELP rabbitmq_detailed_khepri_forced_gcs Number of forced garbage collection runs
rabbitmq_detailed_khepri_forced_gcs 1
# TYPE rabbitmq_detailed_khepri_commands counter
# HELP rabbitmq_detailed_khepri_commands Total number of commands received by a leader
rabbitmq_detailed_khepri_commands 29
# TYPE rabbitmq_detailed_khepri_consistent_queries counter
# HELP rabbitmq_detailed_khepri_consistent_queries Total number of consistent query requests
rabbitmq_detailed_khepri_consistent_queries 0
# TYPE rabbitmq_detailed_khepri_open_segments gauge
# HELP rabbitmq_detailed_khepri_open_segments Number of open segments
rabbitmq_detailed_khepri_open_segments 0
# TYPE rabbitmq_detailed_khepri_term_and_voted_for_updates counter
# HELP rabbitmq_detailed_khepri_term_and_voted_for_updates Total number of updates of term and voted for
rabbitmq_detailed_khepri_term_and_voted_for_updates 1
# TYPE rabbitmq_detailed_khepri_aer_received_follower counter
# HELP rabbitmq_detailed_khepri_aer_received_follower Total number of append entries received by a follower
rabbitmq_detailed_khepri_aer_received_follower 0
# TYPE rabbitmq_detailed_khepri_fetch_term counter
# HELP rabbitmq_detailed_khepri_fetch_term Total number of terms fetched
rabbitmq_detailed_khepri_fetch_term 1
# TYPE rabbitmq_detailed_khepri_release_cursors counter
# HELP rabbitmq_detailed_khepri_release_cursors Total number of updates of the release cursor
rabbitmq_detailed_khepri_release_cursors 0
# TYPE rabbitmq_detailed_khepri_snapshots_written counter
# HELP rabbitmq_detailed_khepri_snapshots_written Total number of snapshots written
rabbitmq_detailed_khepri_snapshots_written 0
# TYPE rabbitmq_detailed_khepri_read_closed_mem_tbl counter
# HELP rabbitmq_detailed_khepri_read_closed_mem_tbl Total number of closed memory tables
rabbitmq_detailed_khepri_read_closed_mem_tbl 0
# TYPE rabbitmq_detailed_khepri_aer_replies_fail counter
# HELP rabbitmq_detailed_khepri_aer_replies_fail Total number of failed append entries
rabbitmq_detailed_khepri_aer_replies_fail 0
# TYPE rabbitmq_detailed_khepri_commit_index counter
# HELP rabbitmq_detailed_khepri_commit_index The current commit index.
rabbitmq_detailed_khepri_commit_index 136
# TYPE rabbitmq_detailed_khepri_checkpoint_index counter
# HELP rabbitmq_detailed_khepri_checkpoint_index The current checkpoint index.
rabbitmq_detailed_khepri_checkpoint_index 0
# TYPE rabbitmq_detailed_khepri_read_ops counter
# HELP rabbitmq_detailed_khepri_read_ops Total number of read ops
rabbitmq_detailed_khepri_read_ops 30
# TYPE rabbitmq_detailed_khepri_last_written_index counter
# HELP rabbitmq_detailed_khepri_last_written_index The last fully written and fsynced index of the log.
rabbitmq_detailed_khepri_last_written_index 136
# TYPE rabbitmq_detailed_khepri_elections counter
# HELP rabbitmq_detailed_khepri_elections Total number of elections
rabbitmq_detailed_khepri_elections 1
# TYPE rabbitmq_detailed_khepri_aer_received_follower_empty counter
# HELP rabbitmq_detailed_khepri_aer_received_follower_empty Total number of empty append entries received by a follower
rabbitmq_detailed_khepri_aer_received_follower_empty 0
# TYPE rabbitmq_detailed_khepri_snapshot_installed counter
# HELP rabbitmq_detailed_khepri_snapshot_installed Total number of snapshots installed
rabbitmq_detailed_khepri_snapshot_installed 0
# TYPE rabbitmq_detailed_khepri_last_index counter
# HELP rabbitmq_detailed_khepri_last_index The last index of the log.
rabbitmq_detailed_khepri_last_index 136
# TYPE rabbitmq_detailed_khepri_msgs_sent counter
# HELP rabbitmq_detailed_khepri_msgs_sent All messages sent (except messages sent to wal)
rabbitmq_detailed_khepri_msgs_sent 0
# TYPE rabbitmq_detailed_khepri_read_cache counter
# HELP rabbitmq_detailed_khepri_read_cache Total number of cache reads
rabbitmq_detailed_khepri_read_cache 29
# TYPE rabbitmq_detailed_khepri_commit_latency gauge
# HELP rabbitmq_detailed_khepri_commit_latency Approximate time taken from an entry being written to the log until it is committed.
rabbitmq_detailed_khepri_commit_latency 0
# TYPE rabbitmq_detailed_khepri_write_ops counter
# HELP rabbitmq_detailed_khepri_write_ops Total number of write ops
rabbitmq_detailed_khepri_write_ops 29
# TYPE rabbitmq_detailed_khepri_aer_replies_success counter
# HELP rabbitmq_detailed_khepri_aer_replies_success Total number of successful append entries received
rabbitmq_detailed_khepri_aer_replies_success 0
# TYPE rabbitmq_detailed_khepri_pre_vote_elections counter
# HELP rabbitmq_detailed_khepri_pre_vote_elections Total number of pre-vote elections
rabbitmq_detailed_khepri_pre_vote_elections 1
# TYPE rabbitmq_detailed_khepri_term counter
# HELP rabbitmq_detailed_khepri_term The current term.
rabbitmq_detailed_khepri_term 8
# TYPE rabbitmq_detailed_khepri_snapshot_index counter
# HELP rabbitmq_detailed_khepri_snapshot_index The current snapshot index.
rabbitmq_detailed_khepri_snapshot_index -1
# TYPE rabbitmq_detailed_khepri_reserved_1 counter
# HELP rabbitmq_detailed_khepri_reserved_1 Reserved counter
rabbitmq_detailed_khepri_reserved_1 0
# TYPE rabbitmq_detailed_khepri_checkpoint_bytes_written counter
# HELP rabbitmq_detailed_khepri_checkpoint_bytes_written Number of checkpoint bytes written
rabbitmq_detailed_khepri_checkpoint_bytes_written 0
# TYPE rabbitmq_detailed_khepri_send_msg_effects_sent counter
# HELP rabbitmq_detailed_khepri_send_msg_effects_sent Total number of send_msg effects executed
rabbitmq_detailed_khepri_send_msg_effects_sent 0
# TYPE rabbitmq_detailed_khepri_checkpoints_written counter
# HELP rabbitmq_detailed_khepri_checkpoints_written Total number of checkpoints written
rabbitmq_detailed_khepri_checkpoints_written 0
# TYPE rabbitmq_detailed_khepri_last_applied gauge
# HELP rabbitmq_detailed_khepri_last_applied The last applied index. Can go backwards if a ra server is restarted.
rabbitmq_detailed_khepri_last_applied 136
# TYPE rabbitmq_detailed_khepri_snapshots_sent counter
# HELP rabbitmq_detailed_khepri_snapshots_sent Total number of snapshots sent
rabbitmq_detailed_khepri_snapshots_sent 0
# TYPE rabbitmq_detailed_khepri_invalid_reply_mode_commands counter
# HELP rabbitmq_detailed_khepri_invalid_reply_mode_commands Total number of commands received with an invalid reply-mode
rabbitmq_detailed_khepri_invalid_reply_mode_commands 0
# TYPE rabbitmq_detailed_khepri_snapshot_bytes_written counter
# HELP rabbitmq_detailed_khepri_snapshot_bytes_written Number of snapshot bytes written (not installed)
rabbitmq_detailed_khepri_snapshot_bytes_written 0
# TYPE rabbitmq_build_info untyped
# HELP rabbitmq_build_info RabbitMQ & Erlang/OTP version info
rabbitmq_build_info{rabbitmq_version="4.1.0+alpha.178.g443be4e.dirty",prometheus_plugin_version="4.1.0+alpha.178.g443be4e.dirty",prometheus_client_version="4.11.0",erlang_version="26.2.1"} 1
# TYPE rabbitmq_identity_info untyped
# HELP rabbitmq_identity_info RabbitMQ node & cluster identity info
rabbitmq_identity_info{rabbitmq_node="rabbit@mango2",rabbitmq_cluster="rabbit@mango2",rabbitmq_cluster_permanent_id="rabbitmq-cluster-id-QuIiiEzWDeP4iD8i4VZkBw"} 1
# TYPE telemetry_scrape_encoded_size_bytes summary
# HELP telemetry_scrape_encoded_size_bytes Scrape size, encoded
# TYPE telemetry_scrape_size_bytes summary
# HELP telemetry_scrape_size_bytes Scrape size, not encoded
telemetry_scrape_size_bytes_count{registry="detailed",content_type="text/plain; version=0.0.4"} 1
telemetry_scrape_size_bytes_sum{registry="detailed",content_type="text/plain; version=0.0.4"} 9685
# TYPE telemetry_scrape_duration_seconds summary
# HELP telemetry_scrape_duration_seconds Scrape duration
telemetry_scrape_duration_seconds_count{registry="detailed",content_type="text/plain; version=0.0.4"} 1
telemetry_scrape_duration_seconds_sum{registry="detailed",content_type="text/plain; version=0.0.4"} 0.005331059

Closes https://github.com/rabbitmq/rabbitmq-server/issues/12142