Move metrics to core/metrics

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

core/metrics/cgroups/cgroups.go

@@ -0,0 +1,81 @@
+//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 cgroups
+
+import (
+	"github.com/containerd/cgroups/v3"
+	v1 "github.com/containerd/containerd/v2/core/metrics/cgroups/v1"
+	v2 "github.com/containerd/containerd/v2/core/metrics/cgroups/v2"
+	"github.com/containerd/containerd/v2/pkg/events"
+	"github.com/containerd/containerd/v2/platforms"
+	"github.com/containerd/containerd/v2/plugins"
+	"github.com/containerd/containerd/v2/runtime"
+	"github.com/containerd/plugin"
+	"github.com/containerd/plugin/registry"
+	metrics "github.com/docker/go-metrics"
+)
+
+// Config for the cgroups monitor
+type Config struct {
+	NoPrometheus bool `toml:"no_prometheus"`
+}
+
+func init() {
+	registry.Register(&plugin.Registration{
+		Type:   plugins.TaskMonitorPlugin,
+		ID:     "cgroups",
+		InitFn: New,
+		Requires: []plugin.Type{
+			plugins.EventPlugin,
+		},
+		Config: &Config{},
+	})
+}
+
+// New returns a new cgroups monitor
+func New(ic *plugin.InitContext) (interface{}, error) {
+	var ns *metrics.Namespace
+	config := ic.Config.(*Config)
+	if !config.NoPrometheus {
+		ns = metrics.NewNamespace("container", "", nil)
+	}
+	var (
+		tm  runtime.TaskMonitor
+		err error
+	)
+
+	ep, err := ic.GetSingle(plugins.EventPlugin)
+	if err != nil {
+		return nil, err
+	}
+
+	if cgroups.Mode() == cgroups.Unified {
+		tm, err = v2.NewTaskMonitor(ic.Context, ep.(events.Publisher), ns)
+	} else {
+		tm, err = v1.NewTaskMonitor(ic.Context, ep.(events.Publisher), ns)
+	}
+	if err != nil {
+		return nil, err
+	}
+	if ns != nil {
+		metrics.Register(ns)
+	}
+	ic.Meta.Platforms = append(ic.Meta.Platforms, platforms.DefaultSpec())
+	return tm, nil
+}