Method execInContainer

internal/cri/server/container_execsync.go:271–288

execInContainer executes a command inside the container synchronously, and redirects stdio stream properly. This function only returns when the exec process exits, this means that: 1) As long as the exec process is running, the goroutine in the cri plugin will be running and wait for the exit code;

(ctx context.Context, id string, opts execOptions)

// this case, the CRI plugin will still have a goroutine waiting for the exec process
// to exit and log the exit code, but dockershim won't.
func (c *criService) execInContainer(ctx context.Context, id string, opts execOptions) (*uint32, error) {
	span := tracing.SpanFromContext(ctx)
	// Get container from our container store.
	cntr, err := c.containerStore.Get(id)

	if err != nil {
		return nil, fmt.Errorf("failed to find container %q in store: %w", id, err)
	}
	id = cntr.ID
	span.SetAttributes(tracing.Attribute("container.id", id))

	state := cntr.Status.Get().State()
	if state != runtime.ContainerState_CONTAINER_RUNNING {
		return nil, fmt.Errorf("container is in %s state", criContainerStateToString(state))
	}

	return c.execInternal(ctx, cntr.Container, id, opts)
}

// drainExecSyncIO drains process IO with timeout after exec init process exits.
//