fix: improve concurrency by making Rest client stateless and moving m…

[cgrinds]

…etadata out of client

[Copilot]

Pull request overview

This PR aims to improve concurrency by removing per-request mutable state from the REST client and moving request-scoped counters/remote metadata out of the client, while making metadata counters safe for concurrent updates.

Changes:

• Convert collector.Metadata counters to atomic.Uint64 and update call sites to use Add/Store/Load.
• Make the tools REST client stateless (no cached request/buffer/remote/token/metadata) and thread-safe by passing request metadata explicitly.
• Propagate Remote and request metadata through collectors/plugins (including adding Plugin.SetRemote) so plugins can observe updated cluster info and report per-run request metrics.

Reviewed changes

Copilot reviewed 64 out of 64 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
pkg/collector/metadata.go	Switch metadata counters to atomic.Uint64 and update Reset() accordingly.
pkg/api/ontapi/zapi/client.go	Use atomic increments for ZAPI client metadata counters.
integration/test/counter_test.go	Update REST client init to return Remote and pass version explicitly when walking templates.
cmd/tools/util.go	Adjust to new REST client Init return value and updated REST fetch signatures.
cmd/tools/rest/rest.go	Thread request metadata through fetch helpers and REST client calls.
cmd/tools/rest/client.go	Remove client state (request/buffer/remote/token/metadata) and accept optional request metadata per call.
cmd/tools/rest/client_test.go	Add concurrency test for GetPlainRest metadata counting.
cmd/poller/poller.go	Update REST calls to pass nil metadata with new REST client signatures.
cmd/poller/plugin/plugin.go	Add SetRemote to plugin interface; cache Remote + per-run RequestMetadata in AbstractPlugin.
cmd/poller/plugin/maxplugin/max.go	Use atomic add for PluginInstances.
cmd/poller/plugin/changelog/changelog.go	Use atomic store for PluginInstances.
cmd/poller/plugin/aggregator/aggregator.go	Use atomic add for PluginInstances.
cmd/poller/collector/collector.go	Call SetRemote before each plugin run; load atomic metadata counters via Load().
cmd/collectors/zapiperf/zapiperf.go	Read ZAPI client metadata using Load().
cmd/collectors/zapi/plugins/snapshotviolation/snapshotviolation.go	Store plugin instance count atomically.
cmd/collectors/zapi/plugins/qtree/qtree.go	Store plugin instance count atomically.
cmd/collectors/zapi/collector/zapi.go	Read ZAPI client metadata using Load().
cmd/collectors/storagegrid/storagegrid.go	Read StorageGrid client metadata using Load().
cmd/collectors/storagegrid/rest/client.go	Use atomic increments for StorageGrid REST client metadata counters.
cmd/collectors/statperf/statperf.go	Replace client-scoped metadata with collector RequestMetadata passed into REST fetches.
cmd/collectors/statperf/plugins/flexcache/flexcache.go	Use plugin RequestMetadata instead of client metadata; update Init call.
cmd/collectors/statperf/parser_test.go	Minor struct literal formatting adjustment.
cmd/collectors/restperf/restperf.go	Replace client-scoped metadata with collector RequestMetadata and thread through fetches.
cmd/collectors/restperf/plugins/volumetopmetrics/volumetopmetrics.go	Switch to plugin RequestMetadata and atomic plugin instance storage.
cmd/collectors/restperf/plugins/volumetag/volumetag.go	Switch to plugin RequestMetadata and updated Init signature usage.
cmd/collectors/restperf/plugins/volume/volume.go	Update test client construction and thread request metadata into FetchAll.
cmd/collectors/restperf/plugins/nic/nic.go	Switch to plugin RequestMetadata and updated Init usage.
cmd/collectors/restperf/plugins/nic/nic_test.go	Update test client construction (no embedded Metadata).
cmd/collectors/restperf/plugins/fcvi/fcvi.go	Switch to plugin RequestMetadata and updated Init usage.
cmd/collectors/restperf/plugins/disk/disk.go	Switch to plugin RequestMetadata and thread into all REST calls.
cmd/collectors/rest/rest.go	Add collector RequestMetadata; update init/cluster-info refresh and stream fetch calls.
cmd/collectors/rest/rest_test.go	Adjust helper construction to use pointer receiver consistently.
cmd/collectors/rest/plugins/vscanpool/vscanpool.go	Switch to plugin RequestMetadata and updated Init usage.
cmd/collectors/rest/plugins/vscanpool/vscanpool_test.go	Update test client construction (no embedded Metadata).
cmd/collectors/rest/plugins/volumeanalytics/volumeanalytics.go	Cache remote via AbstractPlugin.Remote; thread request metadata into analytics fetches.
cmd/collectors/rest/plugins/volume/volume.go	Cache remote via AbstractPlugin.Remote; switch to plugin RequestMetadata.
cmd/collectors/rest/plugins/tag/tag.go	Cache remote via AbstractPlugin.Remote from client.Init.
cmd/collectors/rest/plugins/svm/svm.go	Switch to plugin RequestMetadata and updated Init usage.
cmd/collectors/rest/plugins/snapshotviolation/snapshotviolation.go	Switch to plugin RequestMetadata and thread metadata through stream fetch.
cmd/collectors/rest/plugins/snapmirror/snapmirror.go	Switch to plugin RequestMetadata and thread into REST calls.
cmd/collectors/rest/plugins/securityaccount/securityaccount.go	Switch to plugin RequestMetadata and updated Init usage.
cmd/collectors/rest/plugins/ontaps3service/ontaps3service.go	Switch to plugin RequestMetadata and updated Init usage.
cmd/collectors/rest/plugins/mav/mav.go	Switch to plugin RequestMetadata and updated Init usage.
cmd/collectors/rest/plugins/health/health.go	Cache remote via AbstractPlugin.Remote; switch to plugin RequestMetadata + atomic instance storage.
cmd/collectors/rest/plugins/certificate/certificate.go	Switch to plugin RequestMetadata and updated Init usage.
cmd/collectors/rest/plugins/auditlog/auditlog.go	Switch to plugin RequestMetadata and thread into REST calls.
cmd/collectors/rest/plugins/aggregate/aggregate.go	Switch to plugin RequestMetadata and updated Init usage.
cmd/collectors/power.go	Pass cluster name explicitly (no client remote getter) and update REST fetch signature usage.
cmd/collectors/keyperf/keyperf.go	Switch to collector RequestMetadata and thread into stream fetch.
cmd/collectors/eseriesperf/eseriesperf.go	Read E-series client metadata using Load().
cmd/collectors/eseries/rest/client.go	Use atomic increments for E-series REST client metadata counters.
cmd/collectors/eseries/plugins/ssdcachecapacity/ssdcachecapacity.go	Store plugin instance count atomically.
cmd/collectors/eseries/plugins/hardware/hardware.go	Store plugin instance count atomically.
cmd/collectors/eseries/eseries.go	Read E-series client metadata using Load().
cmd/collectors/ems/ems.go	Use collector Remote instead of REST client Remote() in global labels.
cmd/collectors/discovery.go	Update tools REST Init usage to return Remote (others remain error-only).
cmd/collectors/commonutils.go	Update REST fetch signature usage (FetchAll, FetchSome) with metadata arg.
cmd/collectors/cmperf/cmperf.go	Switch to collector RequestMetadata and read via Load().
cmd/collectors/cisco/plugins/version/version.go	Store Cisco plugin metadata atomically.
cmd/collectors/cisco/plugins/optic/optic.go	Store Cisco plugin metadata atomically.
cmd/collectors/cisco/plugins/networkinterface/networkinterface.go	Store Cisco plugin metadata atomically.
cmd/collectors/cisco/plugins/lldp/lldp.go	Store Cisco plugin metadata atomically.
cmd/collectors/cisco/plugins/environment/environment.go	Store Cisco plugin metadata atomically.
cmd/collectors/cisco/plugins/cdp/cdp.go	Store Cisco plugin metadata atomically.

Comments suppressed due to low confidence (1)

cmd/tools/rest/client.go:263

• invokeWithAuthRetry can call doInvoke() more than once (on auth retry), but the request body is never rewound between calls, and defer buffer.Reset() clears the buffer after the first attempt. This can cause retries (especially POSTs) to send an empty/consumed body. Before each c.client.Do(req) call, reset req.Body from req.GetBody() (or rebuild the request), and don’t reset/clear the body source until all retry attempts are finished.

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