Added optional container restore statistics

This adds the parameter '--print-stats' to 'podman container restore'.
With '--print-stats' Podman will measure how long Podman itself, the OCI
runtime and CRIU requires to restore a checkpoint and print out these
information. CRIU already creates process restore statistics which are
just read in addition to the added measurements. In contrast to just
printing out the ID of the restored container, Podman will now print
out JSON:

 # podman container restore --latest --print-stats
 {
     "podman_restore_duration": 305871,
     "container_statistics": [
         {
             "Id": "47b02e1d474b5d5fe917825e91ac653efa757c91e5a81a368d771a78f6b5ed20",
             "runtime_restore_duration": 140614,
             "criu_statistics": {
                 "forking_time": 5,
                 "restore_time": 67672,
                 "pages_restored": 14
             }
         }
     ]
 }

The output contains 'podman_restore_duration' which contains the
number of microseconds Podman required to restore the checkpoint. The
output also includes 'runtime_restore_duration' which is the time
the runtime needed to restore that specific container. Each container
also includes 'criu_statistics' which displays the timing information
collected by CRIU.

Signed-off-by: Adrian Reber <areber@redhat.com>

1 files changed, 33 insertions, 1 deletions

diff --git a/cmd/podman/containers/restore.go b/cmd/podman/containers/restore.go
index 05214f32c..217adc887 100644
--- a/cmd/podman/containers/restore.go
+++ b/cmd/podman/containers/restore.go
@@ -3,6 +3,7 @@ package containers
 import (
 	"context"
 	"fmt"
+	"time"
 
 	"github.com/containers/common/pkg/completion"
 	"github.com/containers/podman/v3/cmd/podman/common"
@@ -39,6 +40,11 @@ var (
 
 var restoreOptions entities.RestoreOptions
 
+type restoreStatistics struct {
+	PodmanDuration      int64                     `json:"podman_restore_duration"`
+	ContainerStatistics []*entities.RestoreReport `json:"container_statistics"`
+}
+
 func init() {
 	registry.Commands = append(registry.Commands, registry.CliCommand{
 		Command: restoreCommand,
@@ -75,11 +81,19 @@ func init() {
 	flags.StringVar(&restoreOptions.Pod, "pod", "", "Restore container into existing Pod (only works with --import)")
 	_ = restoreCommand.RegisterFlagCompletionFunc("pod", common.AutocompletePodsRunning)
 
+	flags.BoolVar(
+		&restoreOptions.PrintStats,
+		"print-stats",
+		false,
+		"Display restore statistics",
+	)
+
 	validate.AddLatestFlag(restoreCommand, &restoreOptions.Latest)
 }
 
 func restore(cmd *cobra.Command, args []string) error {
 	var errs utils.OutputErrors
+	podmanStart := time.Now()
 	if rootless.IsRootless() {
 		return errors.New("restoring a container requires root")
 	}
@@ -132,12 +146,30 @@ func restore(cmd *cobra.Command, args []string) error {
 	if err != nil {
 		return err
 	}
+	podmanFinished := time.Now()
+
+	var statistics restoreStatistics
+
 	for _, r := range responses {
 		if r.Err == nil {
-			fmt.Println(r.Id)
+			if restoreOptions.PrintStats {
+				statistics.ContainerStatistics = append(statistics.ContainerStatistics, r)
+			} else {
+				fmt.Println(r.Id)
+			}
 		} else {
 			errs = append(errs, r.Err)
 		}
 	}
+
+	if restoreOptions.PrintStats {
+		statistics.PodmanDuration = podmanFinished.Sub(podmanStart).Microseconds()
+		j, err := json.MarshalIndent(statistics, "", "    ")
+		if err != nil {
+			return err
+		}
+		fmt.Println(string(j))
+	}
+
 	return errs.PrintErrors()
 }