server: store containers state on disk

Signed-off-by: Antonio Murdaca <runcom@redhat.com>

oci/container.go

@@ -2,6 +2,7 @@ package oci
 
 import (
 	"fmt"
+	"path/filepath"
 	"sync"
 	"time"
 
@@ -64,6 +65,11 @@ func NewContainer(id string, name string, bundlePath string, logPath string, net
 	return c, nil
 }
 
+// StatePath returns the containers state.json path
+func (c *Container) StatePath() string {
+	return filepath.Join(c.dir, "state.json")
+}
+
 // CreatedAt returns the container creation time
 func (c *Container) CreatedAt() time.Time {
 	return c.state.Created

server/container_create.go

@@ -310,6 +310,8 @@ func (s *Server) CreateContainer(ctx context.Context, req *pb.CreateContainerReq
 		return nil, err
 	}
 
+	s.containerStateToDisk(container)
+
 	resp := &pb.CreateContainerResponse{
 		ContainerId: containerID,
 	}

server/container_start.go

@@ -20,6 +20,8 @@ func (s *Server) StartContainer(ctx context.Context, req *pb.StartContainerReque
 		return nil, fmt.Errorf("failed to start container %s: %v", c.ID(), err)
 	}
 
+	s.containerStateToDisk(c)
+
 	resp := &pb.StartContainerResponse{}
 	logrus.Debugf("StartContainerResponse %+v", resp)
 	return resp, nil

server/container_stop.go

@@ -27,6 +27,8 @@ func (s *Server) StopContainer(ctx context.Context, req *pb.StopContainerRequest
 		}
 	}
 
+	s.containerStateToDisk(c)
+
 	resp := &pb.StopContainerResponse{}
 	logrus.Debugf("StopContainerResponse: %+v", resp)
 	return resp, nil

server/sandbox_run.go

@@ -425,6 +425,8 @@ func (s *Server) RunPodSandbox(ctx context.Context, req *pb.RunPodSandboxRequest
 		return nil, err
 	}
 
+	s.containerStateToDisk(container)
+
 	resp = &pb.RunPodSandboxResponse{PodSandboxId: id}
 	logrus.Debugf("RunPodSandboxResponse: %+v", resp)
 	return resp, nil

server/sandbox_stop.go

@@ -52,6 +52,7 @@ func (s *Server) StopPodSandbox(ctx context.Context, req *pb.StopPodSandboxReque
 				return nil, fmt.Errorf("failed to stop container %s in pod sandbox %s: %v", c.Name(), sb.id, err)
 			}
 		}
+		s.containerStateToDisk(c)
 	}
 
 	resp := &pb.StopPodSandboxResponse{}

server/server.go

@@ -19,6 +19,7 @@ import (
 	"github.com/kubernetes-incubator/cri-o/pkg/storage"
 	"github.com/kubernetes-incubator/cri-o/server/apparmor"
 	"github.com/kubernetes-incubator/cri-o/server/seccomp"
+	"github.com/moby/moby/pkg/ioutils"
 	rspec "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/opencontainers/selinux/go-selinux/label"
 	pb "k8s.io/kubernetes/pkg/kubelet/api/v1alpha1/runtime"
@@ -155,6 +156,20 @@ func (s *Server) loadContainer(id string) error {
 	return s.ctrIDIndex.Add(id)
 }
 
+func (s *Server) containerStateToDisk(c *oci.Container) error {
+	// ignore errors, this is a best effort to have up-to-date info about
+	// a given container before its state gets stored
+	s.runtime.UpdateStatus(c)
+
+	jsonSource, err := ioutils.NewAtomicFileWriter(c.StatePath(), 0644)
+	if err != nil {
+		return err
+	}
+	defer jsonSource.Close()
+	enc := json.NewEncoder(jsonSource)
+	return enc.Encode(s.runtime.ContainerStatus(c))
+}
+
 func configNetNsPath(spec rspec.Spec) (string, error) {
 	for _, ns := range spec.Linux.Namespaces {
 		if ns.Type != rspec.NetworkNamespace {