resmgr: remove old scattered bits of metrics polling.

Remove the old resmgr-triggered polling of policy metrics
and the old resmgr-level polling policy metrics collector.
Implement policy metrics collection in the policy package
itself.

Signed-off-by: Krisztian Litkey <[email protected]>

pkg/resmgr/events.go

@@ -17,42 +17,21 @@ package resmgr
 import (
 	logger "github.com/containers/nri-plugins/pkg/log"
 	"github.com/containers/nri-plugins/pkg/resmgr/cache"
-	"github.com/containers/nri-plugins/pkg/resmgr/metrics"
 )
 
 // Our logger instance for events.
 var evtlog = logger.NewLogger("events")
 
 // setupEventProcessing sets up event and metrics processing.
 func (m *resmgr) setupEventProcessing() error {
-	var err error
-
 	m.events = make(chan interface{}, 8)
 	m.stop = make(chan interface{})
-	options := metrics.Options{
-		PollInterval: opt.MetricsTimer,
-	}
-	if m.metrics, err = metrics.NewMetrics(options); err != nil {
-		return resmgrError("failed to create metrics (pre)processor: %v", err)
-	}
-
-	return nil
-}
-
-func (m *resmgr) startMetricsProcessing() error {
-	if err := m.metrics.Start(); err != nil {
-		return resmgrError("failed to start metrics (pre)processor: %v", err)
-	}
 
 	return nil
 }
 
 // startEventProcessing starts event and metrics processing.
 func (m *resmgr) startEventProcessing() error {
-	if err := m.startMetricsProcessing(); err != nil {
-		return resmgrError("failed to start metrics (pre)processor: %v", err)
-	}
-
 	stop := m.stop
 	go func() {
 		for {
@@ -73,7 +52,6 @@ func (m *resmgr) startEventProcessing() error {
 func (m *resmgr) stopEventProcessing() {
 	if m.stop != nil {
 		close(m.stop)
-		m.metrics.Stop()
 		m.stop = nil
 	}
 }

pkg/resmgr/policy/metrics.go

@@ -0,0 +1,55 @@
+// Copyright The NRI Plugins Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package policy
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+
+	"github.com/containers/nri-plugins/pkg/metrics"
+)
+
+type PolicyCollector struct {
+	policy *policy
+}
+
+func (p *policy) newPolicyCollector() *PolicyCollector {
+	return &PolicyCollector{
+		policy: p,
+	}
+}
+
+func (c *PolicyCollector) register() error {
+	return metrics.Register(c.policy.ActivePolicy(), c, metrics.WithGroup("policy"))
+}
+
+func (c *PolicyCollector) Describe(ch chan<- *prometheus.Desc) {
+	for _, d := range c.policy.active.DescribeMetrics() {
+		ch <- d
+	}
+}
+
+func (c *PolicyCollector) Collect(ch chan<- prometheus.Metric) {
+	polled := c.policy.active.PollMetrics()
+
+	collected, err := c.policy.active.CollectMetrics(polled)
+	if err != nil {
+		log.Error("failed to collect metrics: %v", err)
+		return
+	}
+
+	for _, m := range collected {
+		ch <- m
+	}
+}

pkg/resmgr/policy/policy.go

@@ -147,12 +147,6 @@ type Policy interface {
 	HandleEvent(*events.Policy) (bool, error)
 	// ExportResourceData exports/updates resource data for the container.
 	ExportResourceData(cache.Container)
-	// DescribeMetrics generates policy-specific prometheus metrics data descriptors.
-	DescribeMetrics() []*prometheus.Desc
-	// PollMetrics provides policy metrics for monitoring.
-	PollMetrics() Metrics
-	// CollectMetrics generates prometheus metrics from cached/polled policy-specific metrics data.
-	CollectMetrics(Metrics) ([]prometheus.Metric, error)
 	// GetTopologyZones returns the policy/pool data for 'topology zone' CRDs.
 	GetTopologyZones() []*TopologyZone
 }
@@ -204,11 +198,12 @@ type ZoneAttribute struct {
 
 // Policy instance/state.
 type policy struct {
-	options   Options       // policy options
-	cache     cache.Cache   // system state cache
-	active    Backend       // our active backend
-	system    system.System // system/HW/topology info
-	sendEvent SendEventFn   // function to send event up to the resource manager
+	options   Options          // policy options
+	cache     cache.Cache      // system state cache
+	active    Backend          // our active backend
+	system    system.System    // system/HW/topology info
+	sendEvent SendEventFn      // function to send event up to the resource manager
+	pcollect  *PolicyCollector // policy metrics collector
 }
 
 // backend is a registered Backend.
@@ -225,11 +220,25 @@ var log logger.Logger = logger.NewLogger("policy")
 func NewPolicy(backend Backend, cache cache.Cache, o *Options) (Policy, error) {
 	log.Info("creating '%s' policy...", backend.Name())
 
-	return &policy{
+	p := &policy{
 		cache:   cache,
 		options: *o,
 		active:  backend,
-	}, nil
+	}
+
+	sys, err := system.DiscoverSystem()
+	if err != nil {
+		return nil, policyError("failed to discover system topology: %v", err)
+	}
+	p.system = sys
+
+	pcollect := p.newPolicyCollector()
+	if err := pcollect.register(); err != nil {
+		return nil, policyError("failed to register policy collector: %v", err)
+	}
+	p.pcollect = pcollect
+
+	return p, nil
 }
 
 func (p *policy) ActivePolicy() string {
@@ -241,12 +250,6 @@ func (p *policy) ActivePolicy() string {
 
 // Start starts up policy, preparing it for serving requests.
 func (p *policy) Start(cfg interface{}) error {
-	sys, err := system.DiscoverSystem()
-	if err != nil {
-		return policyError("failed to discover system topology: %v", err)
-	}
-	p.system = sys
-
 	log.Info("activating '%s' policy...", p.active.Name())
 
 	if err := p.active.Setup(&BackendOptions{
@@ -258,7 +261,11 @@ func (p *policy) Start(cfg interface{}) error {
 		return err
 	}
 
-	return p.active.Start()
+	if err := p.active.Start(); err != nil {
+		return err
+	}
+
+	return nil
 }
 
 // Reconfigure the policy.
@@ -315,21 +322,6 @@ func (p *policy) ExportResourceData(c cache.Container) {
 	p.cache.WriteFile(c.GetID(), ExportedResources, 0644, buf.Bytes())
 }
 
-// PollMetrics provides policy metrics for monitoring.
-func (p *policy) PollMetrics() Metrics {
-	return p.active.PollMetrics()
-}
-
-// DescribeMetrics generates policy-specific prometheus metrics data descriptors.
-func (p *policy) DescribeMetrics() []*prometheus.Desc {
-	return p.active.DescribeMetrics()
-}
-
-// CollectMetrics generates prometheus metrics from cached/polled policy-specific metrics data.
-func (p *policy) CollectMetrics(m Metrics) ([]prometheus.Metric, error) {
-	return p.active.CollectMetrics(m)
-}
-
 // GetTopologyZones returns the policy/pool data for 'topology zone' CRDs.
 func (p *policy) GetTopologyZones() []*TopologyZone {
 	return p.active.GetTopologyZones()