Used by workers to get an ActivityTask from the specified activity taskList . This initiates a long poll, where the service holds the HTTP connection open and responds as soon as a task becomes available. The maximum time the service holds on to the request before responding is 60 seconds. If no task is available within 60 seconds, the poll will return an empty result. An empty result, in this context, means that an ActivityTask is returned, but that the value of taskToken is an empty string. If a task is returned, the worker should use its type to identify and process it correctly.

IMPORTANT: Workers should set their client side socket timeout to at least 70 seconds (10 seconds higher than the maximum time service may hold the poll request).

Access Control

You can use IAM policies to control this action's access to Amazon SWF resources as follows:

• Use a Resource element with the domain name to limit the action to only specified domains.
• Use an Action element to allow or deny permission to call this action.
• Constrain the taskList.name parameter by using a Condition element with the swf:taskList.name key to allow the action to access only certain task lists.

If the caller does not have sufficient permissions to invoke the action, or the parameter values fall outside the specified constraints, the action fails by throwing OperationNotPermitted . For details and example IAM policies, see Using IAM to Manage Access to Amazon SWF Workflows.