Send error message to docker/kubectl exec on failure

Containerd uses the last error message sent to the log to
print as failure cause for create/exec. This required a
few changes in the logging logic for runsc:
  - cmd.Errorf/Fatalf: now writes a message with 'error'
    level to containerd log, in addition to stderr and
    debug logs, like before.
  - log.Infof/Warningf/Fatalf: are not sent to containerd
    log anymore. They are mostly used for debugging and not
    useful to containerd. In most cases, --debug-log is
    enabled and this avoids the logs messages from being
    duplicated.
  - stderr is not used as default log destination anymore.
    Some commands assume stdio is for the container/process
    running inside the sandbox and it's better to never use
    it for logging. By default, logs are supressed now.

PiperOrigin-RevId: 251881815

1 files changed, 23 insertions, 0 deletions

diff --git a/runsc/test/integration/exec_test.go b/runsc/test/integration/exec_test.go
index 7af064d79..7c0e61ac3 100644
--- a/runsc/test/integration/exec_test.go
+++ b/runsc/test/integration/exec_test.go
@@ -29,6 +29,7 @@ package integration
 import (
 	"fmt"
 	"strconv"
+	"strings"
 	"syscall"
 	"testing"
 	"time"
@@ -136,3 +137,25 @@ func TestExecJobControl(t *testing.T) {
 		t.Errorf("ws.ExitedStatus got %d, want %d", got, want)
 	}
 }
+
+// Test that failure to exec returns proper error message.
+func TestExecError(t *testing.T) {
+	if err := testutil.Pull("alpine"); err != nil {
+		t.Fatalf("docker pull failed: %v", err)
+	}
+	d := testutil.MakeDocker("exec-error-test")
+
+	// Start the container.
+	if err := d.Run("alpine", "sleep", "1000"); err != nil {
+		t.Fatalf("docker run failed: %v", err)
+	}
+	defer d.CleanUp()
+
+	_, err := d.Exec("no_can_find")
+	if err == nil {
+		t.Fatalf("docker exec didn't fail")
+	}
+	if want := `error finding executable "no_can_find" in PATH`; !strings.Contains(err.Error(), want) {
+		t.Fatalf("docker exec wrong error, got: %s, want: .*%s.*", err.Error(), want)
+	}
+}