[BUG] Image import exec failure logs are hidden

[rhbuf]

What did you do

• How was the cluster created?

k3d cluster create local

• What did you do afterwards?
  Import a non-image tar into k3d to deliberately cause ctr to error

tar -cf test.tar README.md
k3d image import -c local -m direct test.tar

What did you expect to happen

I expected to see the error message from the exec appear in the logs from k3d, but it is shadowed by the err from reading the logs

k3d/pkg/runtimes/docker/node.go

Lines 348 to 363 in 516fe7c

	func execInNode(ctx context.Context, node *k3d.Node, cmd []string, stdin io.ReadCloser) error {
	execConnection, err := executeInNode(ctx, node, cmd, stdin)
	if execConnection != nil {
	defer execConnection.Close()
	}
	if err != nil {
	if execConnection != nil && execConnection.Reader != nil {
	logs, err := io.ReadAll(execConnection.Reader)
	if err != nil {
	return fmt.Errorf("failed to get logs from errored exec process in node '%s': %w", node.Name, err)
	}
	err = fmt.Errorf("%w: Logs from failed access process:\n%s", err, string(logs))
	}
	}
	return err
	}

Screenshots or terminal output

$ k3d image import -c local -m direct out.tar
INFO[0000] Importing image(s) into cluster 'local'      
INFO[0000] Importing images from 1 tarball(s)...        
INFO[0000] Importing images '[out.tar]' into node 'k3d-local-server-0'... 
ERRO[0008] Failed to import image(s) into cluster 'local': could not load image to cluster from stream out.tar: error loading image to cluster, first error: failed to import images in node 'k3d-local-server-0': Exec process in node 'k3d-local-server-0' failed with exit code '1' 
WARN[0008] At least one error occured while trying to import the image(s) into the selected cluster(s) 

Which OS & Architecture

arch: aarch64
cgroupdriver: cgroupfs
cgroupversion: "2"
endpoint: /var/run/docker.sock
filesystem: extfs
name: docker
os: Docker Desktop
ostype: linux
version: 20.10.17

Which version of k3d

k3d version v5.4.4
k3s version v1.23.8-k3s1 (default)

Which version of docker

$ docker version
Client: Docker Engine - Community
 Version:           20.10.18
 API version:       1.41
 Go version:        go1.19.1
 Git commit:        b40c2f6b5d
 Built:             Thu Sep  8 08:19:02 2022
 OS/Arch:           darwin/arm64
 Context:           default
 Experimental:      true

Server: Docker Desktop 4.12.0 (85629)
 Engine:
  Version:          20.10.17
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.17.11
  Git commit:       a89b842
  Built:            Mon Jun  6 23:01:01 2022
  OS/Arch:          linux/arm64
  Experimental:     false
 containerd:
  Version:          1.6.8
  GitCommit:        9cd3357b7fd7218e4aec3eae239db1f68a5a6ec6
 runc:
  Version:          1.1.4
  GitCommit:        v1.1.4-0-g5fd4c4d
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

[rhbuf]

The fix for this is to assign the error from reading the logs to its own variable:

diff --git a/pkg/runtimes/docker/node.go b/pkg/runtimes/docker/node.go
index 5ea6d05d..c73efca2 100644
--- a/pkg/runtimes/docker/node.go
+++ b/pkg/runtimes/docker/node.go
@@ -352,8 +352,8 @@ func execInNode(ctx context.Context, node *k3d.Node, cmd []string, stdin io.Read
 	}
 	if err != nil {
 		if execConnection != nil && execConnection.Reader != nil {
-			logs, err := io.ReadAll(execConnection.Reader)
-			if err != nil {
+			logs, logsErr := io.ReadAll(execConnection.Reader)
+			if logsErr != nil {
 				return fmt.Errorf("failed to get logs from errored exec process in node '%s': %w", node.Name, err)
 			}
 			err = fmt.Errorf("%w: Logs from failed access process:\n%s", err, string(logs))

then the output can be logged successfully:

$ ../k3d/bin/k3d image import -c local -m direct test.tar
INFO[0000] Importing image(s) into cluster 'local'      
INFO[0000] Importing images from 1 tarball(s)...        
INFO[0000] Importing images '[test.tar]' into node 'k3d-local-server-0'... 
ERRO[0001] Failed to import image(s) into cluster 'local': could not load image to cluster from stream test.tar: error loading image to cluster, first error: failed to import images in node 'k3d-local-server-0': Exec process in node 'k3d-local-server-0' failed with exit code '1': Logs from failed access process:
ctr: unrecognized image format 
WARN[0001] At least one error occured while trying to import the image(s) into the selected cluster(s)

I'll put up a PR to fix