resctrl-mon: OTel telemetry via goresctrl pkg/monitor

cmd/plugins/resctrl-mon/metrics.go

@@ -0,0 +1,143 @@
+// 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 main
+
+import (
+	"path/filepath"
+	"strings"
+
+	"github.com/intel/goresctrl/pkg/monitor"
+	"go.opentelemetry.io/otel/attribute"
+	otelmetric "go.opentelemetry.io/otel/metric"
+)
+
+// coreAETFiles are counter files that appear under mon_PERF_PKG_* but are
+// always exported (not gated by perfCounters.enabled).
+var coreAETFiles = map[string]bool{
+	"core_energy": true,
+	"activity":    true,
+}
+
+// resctrlManager is the subset of *monitor.Manager the plugin depends on.
+// Defining it as an interface lets tests substitute a fake whose Reconcile
+// records the live set instead of performing filesystem rmdir, which on tmpfs
+// cannot delete a realistic mon_group the way the resctrl kernel does.
+type resctrlManager interface {
+	EnsureGroup(key, rdtClass string) (*monitor.Group, error)
+	AssignPID(key string, pid int) error
+	Remove(key string) error
+	List() []string
+	Reconcile(live []string) error
+	RegisterOTelInstruments(meter otelmetric.Meter, opts ...monitor.OTelOption) (*monitor.Registration, error)
+}
+
+// setupMetrics registers OTel instruments via the goresctrl adapter.
+func setupMetrics(mgr resctrlManager, cfg telemetryConfig, resctrlRoot string, meter otelmetric.Meter) (*monitor.Registration, error) {
+	return mgr.RegisterOTelInstruments(meter,
+		monitor.WithFilter(perfCounterFilter(cfg)),
+		monitor.WithAttributes(groupAttributesFor(resctrlRoot)),
+	)
+}
+
+// perfCounterFilter returns a FilterFunc that implements the perf counter gate.
+func perfCounterFilter(cfg telemetryConfig) monitor.FilterFunc {
+	return func(r monitor.Reading) bool {
+		// Core AET files (core_energy, activity) are always allowed regardless
+		// of which domain they appear under.
+		if coreAETFiles[r.Name] {
+			return true
+		}
+		// Non-PERF_PKG domains (mon_L3_*) are always allowed.
+		if !strings.HasPrefix(r.Domain, "mon_PERF_PKG_") {
+			return true
+		}
+		// This is a perf counter under mon_PERF_PKG_*. Check the gate.
+		if !cfg.PerfCounters.Enabled {
+			return false
+		}
+		// Apply include/exclude lists if configured.
+		if len(cfg.PerfCounters.Include) > 0 {
+			for _, pattern := range cfg.PerfCounters.Include {
+				if matchGlob(pattern, r.Name) {
+					return true
+				}
+			}
+			return false
+		}
+		if len(cfg.PerfCounters.Exclude) > 0 {
+			for _, pattern := range cfg.PerfCounters.Exclude {
+				if matchGlob(pattern, r.Name) {
+					return false
+				}
+			}
+		}
+		return true
+	}
+}
+
+// groupAttributesFor returns a per-group OTel attribute function bound to the
+// configured resctrl root, which is needed to recognize the root ctrl_group.
+func groupAttributesFor(resctrlRoot string) monitor.AttributeFunc {
+	root := filepath.Clean(resctrlRoot)
+	return func(key, path string) []attribute.KeyValue {
+		return []attribute.KeyValue{
+			attribute.String("k8s.pod.uid", key),
+			attribute.String("resctrl.control_group", controlGroupOf(root, path)),
+			// The manager validates and tracks pod UIDs only, so every exported
+			// group is pod-sourced.
+			attribute.String("resctrl.group.source", "pod"),
+		}
+	}
+}
+
+// matchGlob does simple glob matching (only * is supported as wildcard).
+func matchGlob(pattern, name string) bool {
+	if !strings.Contains(pattern, "*") {
+		return pattern == name
+	}
+	parts := strings.Split(pattern, "*")
+	// The name must start with the segment before the first '*' and end with
+	// the segment after the last '*'.
+	if !strings.HasPrefix(name, parts[0]) {
+		return false
+	}
+	name = name[len(parts[0]):]
+	last := parts[len(parts)-1]
+	if !strings.HasSuffix(name, last) {
+		return false
+	}
+	name = name[:len(name)-len(last)]
+	// Any interior segments must appear in order.
+	for _, seg := range parts[1 : len(parts)-1] {
+		i := strings.Index(name, seg)
+		if i < 0 {
+			return false
+		}
+		name = name[i+len(seg):]
+	}
+	return true
+}
+
+// controlGroupOf extracts the CTRL group name from a mon_group path, relative
+// to the configured resctrl root.
+// e.g. root=/sys/fs/resctrl, "/sys/fs/resctrl/COS1/mon_groups/abc-123" → "COS1"
+// e.g. root=/sys/fs/resctrl, "/sys/fs/resctrl/mon_groups/abc-123" → "" (root)
+func controlGroupOf(resctrlRoot, groupPath string) string {
+	ctrlDir := filepath.Dir(filepath.Dir(groupPath))
+	if filepath.Clean(ctrlDir) == filepath.Clean(resctrlRoot) {
+		return ""
+	}
+	return filepath.Base(ctrlDir)
+}