Add task(s) to the Actions collection.

Input to add one or more Task items to the Actions collection (in other words, enqueue).

Condition

• requires all items in the list to be valid Task items with all required attributes; otherwise rejects whole list and returns 422 Conflict.
• requires the Actions collection to have free memory slots to enqueue the new items; completed, stopped, or failed items in the collection may be removed (oldest first); otherwise,
  • if number of items send by client exceeds maximum number of items in collection, rejects whole list and returns 409 Conflict
  • else if not enough items can be freed, rejects whole list and returns 503 Service Unavailable

On Success

• enqueues the tasks given in the data array
• each Task item is given a unique id
• each Task item is given a status attribute that is initialized with pending
• returns 200 OK listing all items enqueued with ID and status

On Failure

Returns one of the following:

• 409 Conflict, when the request contains more items than the maximum total number of items for the collection
• 415 Unsupported Media Type, when the request content type is not application/vnd.api+json, TODO: allow application/json or empty (tolerant server)
• 422 Unprocessable Content, when invalid items are included or required task-specific attributes are missing
• 503 Service Unavailable, when no more items can be enqueued (but the number of items in the request does not exceed the maximum)

General Background Logic (amended by task-specific background logic)

• when a Task item is executed, its status attribute changes to active
• when a Task item completes successfully, its status attribute changes to completed
• when a Task item completes unsuccessfully, its status attribute changes to stopped
• when a Task item fails, its status attribute changes to failed