Add initial code framework

pkg/server/server.go

@@ -0,0 +1,89 @@
+/*
+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"
+	"net"
+	"os"
+	"syscall"
+	"time"
+
+	"github.com/golang/glog"
+	"google.golang.org/grpc"
+
+	"k8s.io/kubernetes/pkg/kubelet/api/v1alpha1/runtime"
+	"k8s.io/kubernetes/pkg/util/interrupt"
+)
+
+// unixProtocol is the network protocol of unix socket.
+const unixProtocol = "unix"
+
+// CRIContainerdServer is the grpc server of cri-containerd.
+type CRIContainerdServer struct {
+	// addr is the address to serve on.
+	addr string
+	// runtimeService is the cri-containerd runtime service.
+	runtimeService runtime.RuntimeServiceServer
+	// imageService is the cri-containerd image service.
+	imageService runtime.ImageServiceServer
+	// server is the grpc server.
+	server *grpc.Server
+}
+
+// NewCRIContainerdServer creates the cri-containerd grpc server.
+func NewCRIContainerdServer(addr string, r runtime.RuntimeServiceServer, i runtime.ImageServiceServer) *CRIContainerdServer {
+	return &CRIContainerdServer{
+		addr:           addr,
+		runtimeService: r,
+		imageService:   i,
+	}
+}
+
+// Run runs the cri-containerd grpc server.
+func (s *CRIContainerdServer) Run() error {
+	glog.V(2).Infof("Start cri-containerd grpc server")
+	// Unlink to cleanup the previous socket file.
+	err := syscall.Unlink(s.addr)
+	if err != nil && !os.IsNotExist(err) {
+		return fmt.Errorf("failed to unlink socket file %q: %v", s.addr, err)
+	}
+	l, err := net.Listen(unixProtocol, s.addr)
+	if err != nil {
+		return fmt.Errorf("failed to listen on %q: %v", s.addr, err)
+	}
+	// Create the grpc server and register runtime and image services.
+	s.server = grpc.NewServer()
+	runtime.RegisterRuntimeServiceServer(s.server, s.runtimeService)
+	runtime.RegisterImageServiceServer(s.server, s.imageService)
+	// Use interrupt handler to make sure the server to be stopped properly.
+	h := interrupt.New(nil, s.server.Stop)
+	return h.Run(func() error { return s.server.Serve(l) })
+}
+
+// ConnectToContainerd returns a grpc client for containerd.
+func ConnectToContainerd(path string, connectionTimeout time.Duration) (*grpc.ClientConn, error) {
+	// get the containerd client
+	dialOpts := []grpc.DialOption{
+		grpc.WithInsecure(),
+		grpc.WithTimeout(connectionTimeout),
+		grpc.WithDialer(func(addr string, timeout time.Duration) (net.Conn, error) {
+			return net.DialTimeout(unixProtocol, path, timeout)
+		}),
+	}
+	return grpc.Dial(fmt.Sprintf("%s://%s", unixProtocol, path), dialOpts...)
+}