---
alias: user-guide-business-workflow-task-container-dock-pre
render_macros: false
description: "Starts a workflow before a container is docked."
---

# Before Container Docking

Starts a workflow before a **Container** is docked.

![Screenshot of a Business Workflow using If and Throw error to check a Container before docking.](images/business-workflow-task-container-dock-pre.png)

## Event Context

The event provides `Container`, `Resource`, `Location`, `ContainerStateModel`, `ContainerStateModelTransition`, `ResourceStateModel`, `ResourceStateModelTransition`, `Reason`, `ResourceStateModelTransitionReason` to tasks in its branch. Select these values in the value editor when configuring child tasks.

??? example "Before Container Docking"

    Check `Container`, `Resource`, and optional `Location`; reject an incompatible carrier before docking.

## Behavior

The handler runs inside the operation's transaction. An error in the handler can cancel or roll back the operation. An After event runs after the operation boundary, while the transaction is still active.