Move metrics to core/metrics

Signed-off-by: Derek McGowan <derek@mcg.dev>

core/metrics/cgroups/v1/pids.go

@@ -0,0 +1,60 @@
+//go:build linux
+
+/*
+   Copyright The containerd Authors.
+
+   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 v1
+
+import (
+	v1 "github.com/containerd/containerd/v2/core/metrics/types/v1"
+	metrics "github.com/docker/go-metrics"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var pidMetrics = []*metric{
+	{
+		name: "pids",
+		help: "The limit to the number of pids allowed",
+		unit: metrics.Unit("limit"),
+		vt:   prometheus.GaugeValue,
+		getValues: func(stats *v1.Metrics) []value {
+			if stats.Pids == nil {
+				return nil
+			}
+			return []value{
+				{
+					v: float64(stats.Pids.Limit),
+				},
+			}
+		},
+	},
+	{
+		name: "pids",
+		help: "The current number of pids",
+		unit: metrics.Unit("current"),
+		vt:   prometheus.GaugeValue,
+		getValues: func(stats *v1.Metrics) []value {
+			if stats.Pids == nil {
+				return nil
+			}
+			return []value{
+				{
+					v: float64(stats.Pids.Current),
+				},
+			}
+		},
+	},
+}