Mirantis/virtlet

/*
Copyright 2018 Mirantis

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 manager

import (
    "net"
    "os"
    "strings"
    "syscall"

    "github.com/ghodss/yaml"
    "github.com/golang/glog"
    "golang.org/x/net/context"
    "google.golang.org/grpc"
    kubeapi "k8s.io/kubernetes/pkg/kubelet/apis/cri/runtime/v1alpha2"
)

const (
    criErrorLogLevel   = 2
    criRequestLogLevel = 3
    criNoisyLogLevel   = 4
    criListLogLevel    = 5
)

// Server wraps a gRPC server and provides listener setup and request
// logging.
type Server struct {
    server *grpc.Server
}

// NewServer creates a new Server.
func NewServer() *Server {
    return &Server{
        server: grpc.NewServer(grpc.UnaryInterceptor(func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (resp interface{}, err error) {
            return intercept(ctx, req, info, handler)
        })),
    }
}

// Serve set up a listener on unix socket, than it passes that listener to
// main loop of grpc server which handles CRI calls.
func (s *Server) Serve(addr string) error {
    if err := syscall.Unlink(addr); err != nil && !os.IsNotExist(err) {
        return err
    }
    ln, err := net.Listen("unix", addr)
    if err != nil {
        return err
    }
    defer ln.Close()
    return s.server.Serve(ln)
}

// Stop halts the manager.
func (s *Server) Stop() {
    s.server.Stop()
}

// Register registers CRI Runtime and Image services
func (s *Server) Register(runtimeService kubeapi.RuntimeServiceServer, imageService kubeapi.ImageServiceServer) {
    kubeapi.RegisterRuntimeServiceServer(s.server, runtimeService)
    kubeapi.RegisterImageServiceServer(s.server, imageService)
}

func logLevelForMethod(fullMethod string) glog.Level {
    idx := strings.LastIndex(fullMethod, "/")
    if idx < 0 {
        return criNoisyLogLevel
    }
    methodName := fullMethod[idx+1:]
    switch {
    case strings.Contains(methodName, "Status"):
        return criNoisyLogLevel
    case strings.Contains(methodName, "Version"):
        return criNoisyLogLevel
    case strings.Contains(methodName, "List"):
        return criListLogLevel
    case methodName == "ImageFsInfo":
        return criListLogLevel
    default:
        return criRequestLogLevel
    }
}

func dump(v interface{}) string {
    out, err := yaml.Marshal(v)
    if err != nil {
        return "<marshalling error>"
    }
    return string(out)
}

func intercept(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
    logLevel := logLevelForMethod(info.FullMethod)
    if glog.V(logLevel) {
        glog.Infof("ENTER: %s():\n%s", info.FullMethod, dump(req))
    }
    resp, err := handler(ctx, req)
    switch {
    case err != nil && !bool(glog.V(criErrorLogLevel)):
        // do nothing
    case err != nil:
        glog.Errorf("FAIL: %s(): %v", info.FullMethod, err)
    case bool(glog.V(logLevel)):
        glog.Infof("LEAVE: %s()\n%s", info.FullMethod, dump(resp))
    }
    return resp, err
}