Revert "Revert "feat: backup revolution""

This reverts commit 2c515ce70a.

pkg/upstream/container/exec.go

@@ -13,7 +13,10 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
-func RunExec(dockerCli command.Cli, client *apiclient.Client, containerID string, execConfig *types.ExecConfig) error {
+// RunExec runs a command on a remote container. io.Writer corresponds to the
+// command output.
+func RunExec(dockerCli command.Cli, client *apiclient.Client, containerID string,
+	execConfig *types.ExecConfig) (io.Writer, error) {
 	ctx := context.Background()
 
 	// We need to check the tty _before_ we do the ContainerExecCreate, because
@@ -21,22 +24,22 @@ func RunExec(dockerCli command.Cli, client *apiclient.Client, containerID string
 	// there's no easy way to clean those up). But also in order to make "not
 	// exist" errors take precedence we do a dummy inspect first.
 	if _, err := client.ContainerInspect(ctx, containerID); err != nil {
-		return err
+		return nil, err
 	}
 	if !execConfig.Detach {
 		if err := dockerCli.In().CheckTty(execConfig.AttachStdin, execConfig.Tty); err != nil {
-			return err
+			return nil, err
 		}
 	}
 
 	response, err := client.ContainerExecCreate(ctx, containerID, *execConfig)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
 	execID := response.ID
 	if execID == "" {
-		return errors.New("exec ID empty")
+		return nil, errors.New("exec ID empty")
 	}
 
 	if execConfig.Detach {
@@ -44,13 +47,13 @@ func RunExec(dockerCli command.Cli, client *apiclient.Client, containerID string
 			Detach: execConfig.Detach,
 			Tty:    execConfig.Tty,
 		}
-		return client.ContainerExecStart(ctx, execID, execStartCheck)
+		return nil, client.ContainerExecStart(ctx, execID, execStartCheck)
 	}
 	return interactiveExec(ctx, dockerCli, client, execConfig, execID)
 }
 
 func interactiveExec(ctx context.Context, dockerCli command.Cli, client *apiclient.Client,
-	execConfig *types.ExecConfig, execID string) error {
+	execConfig *types.ExecConfig, execID string) (io.Writer, error) {
 	// Interactive exec requested.
 	var (
 		out, stderr io.Writer
@@ -76,7 +79,7 @@ func interactiveExec(ctx context.Context, dockerCli command.Cli, client *apiclie
 	}
 	resp, err := client.ContainerExecAttach(ctx, execID, execStartCheck)
 	if err != nil {
-		return err
+		return out, err
 	}
 	defer resp.Close()
 
@@ -107,10 +110,10 @@ func interactiveExec(ctx context.Context, dockerCli command.Cli, client *apiclie
 
 	if err := <-errCh; err != nil {
 		logrus.Debugf("Error hijack: %s", err)
-		return err
+		return out, err
 	}
 
-	return getExecExitStatus(ctx, client, execID)
+	return out, getExecExitStatus(ctx, client, execID)
 }
 
 func getExecExitStatus(ctx context.Context, client apiclient.ContainerAPIClient, execID string) error {