[RFC] cgroup2: the first cut (yet another version)

Protobuild.toml

@@ -37,3 +37,10 @@ ignore_files = [
 	"google/protobuf/descriptor.proto",
 	"gogoproto/gogo.proto"
 ]
+[[descriptors]]
+prefix = "github.com/containerd/cgroups/v2/stats"
+target = "v2/stats/metrics.pb.txt"
+ignore_files = [
+	"google/protobuf/descriptor.proto",
+	"gogoproto/gogo.proto"
+]

cmd/cgroups-playground/main.go

@@ -0,0 +1,58 @@
+/*
+   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 main
+
+import (
+	"os"
+
+	"github.com/containerd/cgroups/v2"
+	"github.com/sirupsen/logrus"
+)
+
+func main() {
+	if err := xmain(); err != nil {
+		logrus.Fatalf("%+v", err)
+	}
+}
+
+func xmain() error {
+	pid := os.Getpid()
+	g, err := v2.PidGroupPath(pid)
+	if err != nil {
+		return err
+	}
+	unifiedMountpoint := "/sys/fs/cgroup"
+	logrus.Infof("Loading V2 for %q (PID %d), mountpoint=%q", g, pid, unifiedMountpoint)
+	cg, err := v2.Load(unifiedMountpoint, g)
+	if err != nil {
+		return err
+	}
+	processes, err := cg.Processes(true)
+	if err != nil {
+		return err
+	}
+	logrus.Infof("Has %d processes (recursively)", len(processes))
+	for i, s := range processes {
+		logrus.Infof("Process %d: %d", i, s.Pid)
+	}
+	subsystems := cg.Subsystems()
+	logrus.Infof("Has %d subsystems", len(subsystems))
+	for i, s := range subsystems {
+		logrus.Infof("Subsystem %d: %q", i, s.Name())
+	}
+	return nil
+}

go.mod

@@ -9,5 +9,6 @@ require (
 	github.com/gogo/protobuf v1.2.1
 	github.com/opencontainers/runtime-spec v0.1.2-0.20190507144316-5b71a03e2700
 	github.com/pkg/errors v0.8.1
+	github.com/sirupsen/logrus v1.4.2
 	golang.org/x/sys v0.0.0-20190514135907-3a4b5fb9f71f
 )

go.sum

@@ -2,6 +2,7 @@ github.com/coreos/go-systemd v0.0.0-20181030182848-ad9ff7f9a9ff h1:bI9r9ZUi2/EmS
 github.com/coreos/go-systemd v0.0.0-20181030182848-ad9ff7f9a9ff/go.mod h1:F5haX7vjVVG0kc13fIWeqUViNPyEJxv/OmvnBo0Yme4=
 github.com/coreos/go-systemd v0.0.0-20190321100706-95778dfbb74e h1:Wf6HqHfScWJN9/ZjdUKyjop4mf3Qdd+1TvvltAvM3m8=
 github.com/coreos/go-systemd v0.0.0-20190321100706-95778dfbb74e/go.mod h1:F5haX7vjVVG0kc13fIWeqUViNPyEJxv/OmvnBo0Yme4=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/docker/go-units v0.4.0 h1:3uh0PgVws3nIA0Q+MwDC8yjEPf9zjRfZZWXZYDct3Tw=
 github.com/docker/go-units v0.4.0/go.mod h1:fgPhTUdO+D/Jk86RDLlptpiXQzgHJF7gydDDbaIK4Dk=
 github.com/godbus/dbus v0.0.0-20190422162347-ade71ed3457e h1:BWhy2j3IXJhjCbC68FptL43tDKIq8FladmaTs3Xs7Z8=
@@ -12,10 +13,17 @@ github.com/gogo/protobuf v1.2.1 h1:/s5zKNz0uPFCZ5hddgPdo2TK2TVrUNMn0OOX8/aZMTE=
 github.com/gogo/protobuf v1.2.1/go.mod h1:hp+jE20tsWTFYpLwKvXlhS1hjn+gTNwPg2I6zVXpSg4=
 github.com/kisielk/errcheck v1.1.0/go.mod h1:EZBBE59ingxPouuu3KfxchcWSUPOHkagtvWXihfKN4Q=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
+github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/opencontainers/runtime-spec v0.1.2-0.20190507144316-5b71a03e2700 h1:eNUVfm/RFLIi1G7flU5/ZRTHvd4kcVuzfRnL6OFlzCI=
 github.com/opencontainers/runtime-spec v0.1.2-0.20190507144316-5b71a03e2700/go.mod h1:jwyrGlmzljRJv/Fgzds9SsS/C5hL+LL3ko9hs6T5lQ0=
 github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/sirupsen/logrus v1.4.2 h1:SPIRibHv4MatM3XXNO2BJeFLZwZ2LvZgfQ5+UNI2im4=
+github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=
+github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+golang.org/x/sys v0.0.0-20190422165155-953cdadca894/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190514135907-3a4b5fb9f71f h1:Xab8gg26GrI/x3RNdVhVkHHM1XLyGeRBEvz4Q5x4YW8=
 golang.org/x/sys v0.0.0-20190514135907-3a4b5fb9f71f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/tools v0.0.0-20180221164845-07fd8470d635/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=