Add initial sandbox management implementation

Signed-off-by: Random-Liu <lantaol@google.com>

pkg/server/helpers.go

@@ -0,0 +1,125 @@
+/*
+Copyright 2017 The Kubernetes 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 server
+
+import (
+	"fmt"
+	"path/filepath"
+	"strings"
+
+	"github.com/docker/docker/pkg/stringid"
+	"github.com/docker/docker/pkg/truncindex"
+	"google.golang.org/grpc"
+
+	"github.com/containerd/containerd"
+
+	"github.com/kubernetes-incubator/cri-containerd/pkg/metadata"
+
+	"k8s.io/kubernetes/pkg/kubelet/api/v1alpha1/runtime"
+)
+
+const (
+	// relativeRootfsPath is the rootfs path relative to bundle path.
+	relativeRootfsPath = "rootfs"
+	// defaultRuntime is the runtime to use in containerd. We may support
+	// other runtime in the future.
+	defaultRuntime = "linux"
+	// sandboxesDir contains all sandbox root. A sandbox root is the running
+	// directory of the sandbox, all files created for the sandbox will be
+	// placed under this directory.
+	sandboxesDir = "sandboxes"
+	// stdinNamedPipe is the name of stdin named pipe.
+	stdinNamedPipe = "stdin"
+	// stdoutNamedPipe is the name of stdout named pipe.
+	stdoutNamedPipe = "stdout"
+	// stderrNamedPipe is the name of stderr named pipe.
+	stderrNamedPipe = "stderr"
+	// Delimiter used to construct container/sandbox names.
+	nameDelimiter = "_"
+	// netNSFormat is the format of network namespace of a process.
+	netNSFormat = "/proc/%v/ns/net"
+)
+
+// generateID generates a random unique id.
+func generateID() string {
+	return stringid.GenerateNonCryptoID()
+}
+
+// makeSandboxName generates sandbox name from sandbox metadata. The name
+// generated is unique as long as sandbox metadata is unique.
+func makeSandboxName(s *runtime.PodSandboxMetadata) string {
+	return strings.Join([]string{
+		s.Name,      // 0
+		s.Namespace, // 1
+		s.Uid,       // 2
+		fmt.Sprintf("%d", s.Attempt), // 3
+	}, nameDelimiter)
+}
+
+// getCgroupsPath generates container cgroups path.
+func getCgroupsPath(cgroupsParent string, id string) string {
+	// TODO(random-liu): [P0] Handle systemd.
+	return filepath.Join(cgroupsParent, id)
+}
+
+// getSandboxRootDir returns the root directory for managing sandbox files,
+// e.g. named pipes.
+func getSandboxRootDir(rootDir, id string) string {
+	return filepath.Join(rootDir, sandboxesDir, id)
+}
+
+// getStreamingPipes returns the stdin/stdout/stderr pipes path in the root.
+func getStreamingPipes(rootDir string) (string, string, string) {
+	stdin := filepath.Join(rootDir, stdinNamedPipe)
+	stdout := filepath.Join(rootDir, stdoutNamedPipe)
+	stderr := filepath.Join(rootDir, stderrNamedPipe)
+	return stdin, stdout, stderr
+}
+
+// getNetworkNamespace returns the network namespace of a process.
+func getNetworkNamespace(pid uint32) string {
+	return fmt.Sprintf(netNSFormat, pid)
+}
+
+// isContainerdContainerNotExistError checks whether a grpc error is containerd
+// ErrContainerNotExist error.
+// TODO(random-liu): Containerd should expose error better through api.
+func isContainerdContainerNotExistError(grpcError error) bool {
+	return grpc.ErrorDesc(grpcError) == containerd.ErrContainerNotExist.Error()
+}
+
+// getSandbox gets the sandbox metadata from the sandbox store. It returns nil without
+// error if the sandbox metadata is not found. It also tries to get full sandbox id and
+// retry if the sandbox metadata is not found with the initial id.
+func (c *criContainerdService) getSandbox(id string) (*metadata.SandboxMetadata, error) {
+	sandbox, err := c.sandboxStore.Get(id)
+	if err != nil {
+		return nil, fmt.Errorf("sandbox metadata not found: %v", err)
+	}
+	if sandbox != nil {
+		return sandbox, nil
+	}
+	// sandbox is not found in metadata store, try to extract full id.
+	id, err = c.sandboxIDIndex.Get(id)
+	if err != nil {
+		if err == truncindex.ErrNotExist {
+			return nil, nil
+		}
+		return nil, fmt.Errorf("sandbox id not found: %v", err)
+	}
+	return c.sandboxStore.Get(id)
+}