Add controller RPC metrics export

[theyoprst]

Summary

Implements SLURM controller RPC metrics export functionality for monitoring controller performance.

Changes

• RPC Metrics by Message Type: Exports slurm_controller_rpc_calls_total and slurm_controller_rpc_duration_seconds_total metrics with message_type labels
• RPC Metrics by User: Exports slurm_controller_rpc_user_calls_total and slurm_controller_rpc_user_duration_seconds_total metrics with user and user_id labels
• Controller Metrics: Exports slurm_controller_server_thread_count gauge metric

New Metrics Output

slurm_controller_rpc_calls_total{message_type="MESSAGE_NODE_REGISTRATION_STATUS"} 14
slurm_controller_rpc_calls_total{message_type="REQUEST_JOB_INFO"} 370
slurm_controller_rpc_calls_total{message_type="REQUEST_NODE_INFO"} 742
slurm_controller_rpc_calls_total{message_type="REQUEST_NODE_INFO_SINGLE"} 356
slurm_controller_rpc_calls_total{message_type="REQUEST_PARTITION_INFO"} 1100
slurm_controller_rpc_calls_total{message_type="REQUEST_PING"} 536
slurm_controller_rpc_calls_total{message_type="REQUEST_STATS_INFO"} 4

slurm_controller_rpc_duration_seconds_total{message_type="MESSAGE_NODE_REGISTRATION_STATUS"} 0.001678
slurm_controller_rpc_duration_seconds_total{message_type="REQUEST_JOB_INFO"} 0.03879
slurm_controller_rpc_duration_seconds_total{message_type="REQUEST_NODE_INFO"} 0.077907
slurm_controller_rpc_duration_seconds_total{message_type="REQUEST_NODE_INFO_SINGLE"} 0.020751
slurm_controller_rpc_duration_seconds_total{message_type="REQUEST_PARTITION_INFO"} 0.062916
slurm_controller_rpc_duration_seconds_total{message_type="REQUEST_PING"} 0.018569
slurm_controller_rpc_duration_seconds_total{message_type="REQUEST_STATS_INFO"} 0.00024

slurm_controller_rpc_user_calls_total{user="root",user_id="0"} 3122
slurm_controller_rpc_user_duration_seconds_total{user="root",user_id="0"} 0.220851

slurm_controller_server_thread_count 1

Resolves #1027

[Copilot]

Pull Request Overview

Implements controller-side RPC diagnostics export for Prometheus by introducing a new GetDiag API call and wiring its data into the metrics collector.

• Adds GetDiag to the Slurm API interface, client implementation, and mock.
• Defines and registers four RPC-related counters and one gauge for server threads.
• Extends unit tests to verify RPC metrics output and edge‐case handling.

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
internal/slurmapi/interface.go	Added GetDiag to the Client interface
internal/slurmapi/fake/mock_client.go	Implemented mock methods for GetDiag
internal/slurmapi/client.go	Implemented GetDiag using SlurmV0041GetDiagWithResponse and error checks
internal/exporter/collector.go	Defined RPC and thread‐count metric descriptors and wired them into Collect
internal/exporter/collector_test.go	Extended tests to assert presence/absence of new metrics

Comments suppressed due to low confidence (1)

internal/exporter/collector_test.go:11

• You’ve imported the same package twice under two names (api and slurmapispec), which will cause a compile error. Remove the redundant import alias.

	slurmapispec "github.com/SlinkyProject/slurm-client/api/v0041"