Extend checkpoint e2e test to check for results

When the e2e_node/checkpoint_container.go test was introduced no CRI
implementation supported the new CheckpointContainer RPC yet.

With the release of CRI-O 1.25 the CheckpointContainer is implemented
and the test has been extended to see if the content of the checkpoint
is as expected.

The test is skipped if the ContainerCheckpoint feature gate is disabled
or if the CRI implementation does not support the CheckpointContainer
RPC.

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

test/e2e_node/checkpoint_container.go

@@ -17,9 +17,13 @@ limitations under the License.
 package e2enode
 
 import (
+	"archive/tar"
 	"context"
+	"encoding/json"
 	"fmt"
+	"io"
 	"net/http"
+	"os"
 	"strings"
 	"time"
 
@@ -41,6 +45,10 @@ const (
 	proxyTimeout = 2 * time.Minute
 )
 
+type checkpointResult struct {
+	Items []string `json:"items"`
+}
+
 // proxyPostRequest performs a post on a node proxy endpoint given the nodename and rest client.
 func proxyPostRequest(ctx context.Context, c clientset.Interface, node, endpoint string, port int) (restclient.Result, error) {
 	// proxy tends to hang in some cases when Node is not ready. Add an artificial timeout for this call. #22165
@@ -150,10 +158,51 @@ var _ = SIGDescribe("Checkpoint Container [NodeFeature:CheckpointContainer]", fu
 		}
 
 		framework.ExpectNoError(err)
-		// TODO: once a container engine implements the Checkpoint CRI API this needs
-		// to be extended to handle it.
-		//
+
 		// Checkpointing actually worked. Verify that the checkpoint exists and that
 		// it is a checkpoint.
+
+		raw, err := result.Raw()
+		framework.ExpectNoError(err)
+		answer := checkpointResult{}
+		err = json.Unmarshal(raw, &answer)
+		framework.ExpectNoError(err)
+
+		for _, item := range answer.Items {
+			// Check that the file exists
+			_, err := os.Stat(item)
+			framework.ExpectNoError(err)
+			// Check the content of the tar file
+			// At least looking for the following files
+			//  * spec.dump
+			//  * config.dump
+			//  * checkpoint/inventory.img
+			// If these files exist in the checkpoint archive it is
+			// probably a complete checkpoint.
+			checkForFiles := map[string]bool{
+				"spec.dump":                false,
+				"config.dump":              false,
+				"checkpoint/inventory.img": false,
+			}
+			fileReader, err := os.Open(item)
+			framework.ExpectNoError(err)
+			tr := tar.NewReader(fileReader)
+			for {
+				hdr, err := tr.Next()
+				if err == io.EOF {
+					// End of archive
+					break
+				}
+				framework.ExpectNoError(err)
+				if _, key := checkForFiles[hdr.Name]; key {
+					checkForFiles[hdr.Name] = true
+				}
+			}
+			for fileName := range checkForFiles {
+				framework.ExpectEqual(checkForFiles[fileName], true)
+			}
+			// cleanup checkpoint archive
+			os.RemoveAll(item)
+		}
 	})
 })