podman support: Create Podman handler.

Signed-off-by: Paweł Szulik <paul.szulik@gmail.com>

container/container.go

@@ -35,6 +35,7 @@ const (
 	ContainerTypeCrio
 	ContainerTypeContainerd
 	ContainerTypeMesos
+	ContainerTypePodman
 )
 
 // Interface for container operation handlers.

container/podman/client.go

@@ -0,0 +1,58 @@
+// Copyright 2021 Google Inc. 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 podman
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"net/http"
+	urllib "net/url"
+)
+
+type clientKey struct{}
+
+func (c clientKey) String() string {
+	return "client"
+}
+
+type Connection struct {
+	URI    *urllib.URL
+	Client *http.Client
+}
+
+func client(ctx *context.Context) (*Connection, error) {
+	url, err := urllib.Parse(*endpointFlag)
+	if err != nil {
+		return nil, err
+	}
+
+	switch url.Scheme {
+	case "unix":
+		connection := Connection{URI: url}
+		connection.Client = &http.Client{
+			Transport: &http.Transport{
+				DialContext: func(ctx context.Context, _, _ string) (net.Conn, error) {
+					return (&net.Dialer{}).DialContext(ctx, "unix", url.Path)
+				},
+				DisableCompression: true,
+			},
+		}
+		*ctx = context.WithValue(*ctx, clientKey{}, &connection)
+		return &connection, nil
+	}
+
+	return nil, fmt.Errorf("couldn't get podman client")
+}

container/podman/factory.go

@@ -0,0 +1,113 @@
+// Copyright 2021 Google Inc. 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 podman
+
+import (
+	"flag"
+	"fmt"
+	"path"
+	"sync"
+	"time"
+
+	"github.com/google/cadvisor/container"
+	"github.com/google/cadvisor/container/docker"
+	dockerutil "github.com/google/cadvisor/container/docker/utils"
+	"github.com/google/cadvisor/devicemapper"
+	"github.com/google/cadvisor/fs"
+	info "github.com/google/cadvisor/info/v1"
+	"github.com/google/cadvisor/zfs"
+)
+
+const (
+	rootDirRetries     = 5
+	rootDirRetryPeriod = time.Second
+	containerBaseName  = "container"
+)
+
+var (
+	endpointFlag = flag.String("podman", "unix:///var/run/podman/podman.sock", "podman endpoint")
+)
+
+var (
+	rootDir     string
+	rootDirOnce sync.Once
+)
+
+func RootDir() string {
+	rootDirOnce.Do(func() {
+		for i := 0; i < rootDirRetries; i++ {
+			status, err := Status()
+			if err == nil && status.RootDir != "" {
+				rootDir = status.RootDir
+				break
+			} else {
+				time.Sleep(rootDirRetryPeriod)
+			}
+		}
+	})
+	return rootDir
+}
+
+type podmanFactory struct {
+	// Information about the mounted cgroup subsystems.
+	machineInfoFactory info.MachineInfoFactory
+
+	storageDriver docker.StorageDriver
+	storageDir    string
+
+	cgroupSubsystem map[string]string
+
+	fsInfo fs.FsInfo
+
+	metrics container.MetricSet
+
+	thinPoolName    string
+	thinPoolWatcher *devicemapper.ThinPoolWatcher
+
+	zfsWatcher *zfs.ZfsWatcher
+}
+
+func (f *podmanFactory) CanHandleAndAccept(name string) (handle bool, accept bool, err error) {
+	// Rootless
+	if path.Base(name) == containerBaseName {
+		name, _ = path.Split(name)
+	}
+	if !dockerutil.IsContainerName(name) {
+		return false, false, nil
+	}
+
+	id := dockerutil.ContainerNameToId(name)
+
+	ctnr, err := InspectContainer(id)
+	if err != nil || !ctnr.State.Running {
+		return false, true, fmt.Errorf("error inspecting container: %v", err)
+	}
+
+	return true, true, nil
+}
+
+func (f *podmanFactory) DebugInfo() map[string][]string {
+	return map[string][]string{}
+}
+
+func (f *podmanFactory) String() string {
+	return "podman"
+}
+
+func (f *podmanFactory) NewContainerHandler(name string, metadataEnvAllowList []string, inHostNamespace bool) (handler container.ContainerHandler, err error) {
+	return newPodmanContainerHandler(name, f.machineInfoFactory, f.fsInfo,
+		f.storageDriver, f.storageDir, f.cgroupSubsystem, inHostNamespace,
+		metadataEnvAllowList, f.metrics, f.thinPoolName, f.thinPoolWatcher, f.zfsWatcher)
+}

container/podman/fs.go

@@ -0,0 +1,54 @@
+// Copyright 2022 Google Inc. 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 podman
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/google/cadvisor/container/docker"
+)
+
+const (
+	containersJSONFilename = "containers.json"
+)
+
+type containersJSON struct {
+	ID    string `json:"id"`
+	Layer string `json:"layer"`
+	// rest in unnecessary
+}
+
+func rwLayerID(storageDriver docker.StorageDriver, storageDir string, containerID string) (string, error) {
+	data, err := os.ReadFile(filepath.Join(storageDir, string(storageDriver)+"-containers", containersJSONFilename))
+	if err != nil {
+		return "", err
+	}
+	var containers []containersJSON
+	err = json.Unmarshal(data, &containers)
+	if err != nil {
+		return "", err
+	}
+
+	for _, c := range containers {
+		if c.ID == containerID {
+			return c.Layer, nil
+		}
+	}
+
+	return "", fmt.Errorf("unable to determine %v rw layer id", containerID)
+}