Globus Flows Action Provider

Globus Compute exposes an asynchronous Action Provider interface to allow functions to be used in a Globus Flow.

The Globus Compute Action Provider interface uses:

• ActionUrl – ‘https://compute.actions.globus.org’ Updated Apr 2023 [1]

[1]

The previous version of the Action Provider, deprecated April 2023, had an ActionUrl of https://dev.funcx.org/automate along with a required ActionScope. The current Action Provider is backwards compatible, provided the ActionUrl is updated to the new URL and the ActionScope removed. (The ActionScope is now populated from the Action Provider’s metadata URL)

Action Input Schema

The Action Provider input schema accepts input for a single task, plus, optionally, a list of task objects each with a similar schema.

Each run input consists of the required 'endpoint' and 'function' fields which are uuid string identifiers of the endpoint and function to be executed, and two optional arguments 'args' and 'kwargs' which are a list and an object respectively representing inputs to the function.

Notes

• The 'tasks' field can be empty, if only a single invocation is desired. The single invocation uses 'endpoint' and 'function' in the main input body, in addition to 'args' and 'kwargs'.

• 'args' can be a single item or a list of items.

• 'payload' can be used in place of 'kwargs' to specify kwargs to the function. This is for backwards compatibility with a prior implementation of the Action Provider which only recognized 'payload'.

'endpoint': '<COMPUTE_ENDPOINT_UUID>',
'function': '<COMPUTE_FUNCTION_UUID>',
'args':  [ 'Argument 1', 2, 'Third Argument' ],
'kwargs': { "kwarg_one": "abc", "kwarg_two": 234 },
'tasks': [
           {
             'endpoint': '<COMPUTE_ENDPOINT_UUID>',
             'function': '<COMPUTE_FUNCTION_UUID>',
             'args':  [LIST OF ARGS],
             'payload': {DICT OF INPUT ARGS}
           },
           { ...},
           { ...},
         ]

When defining a Globus Compute function to use within a flow it is recommended to define the specific args and kwargs that will be passed in as payload. If the arguments are not known, a function can be defined to accept arbitrary args and kwargs using the * and ** operators, e.g.:

'Parameters': {'tasks': [{'endpoint': '$.input.fx_ep',
                          'function': '$.input.fx_fn',
                          'args': '$.input.fx_args',
                          'kwargs': '$.input.fx_kwargs'}]},

def my_function(*args, **kwargs):
    ...

Action Output

The output of the Action from Globus Compute will reside in the ‘details’ field of the output. The details section has two lists, 'result' and 'results'.

The 'result' field contains a list of task results from the submitted functions. This field is meant to be backwards compatible with an earlier implementation of the Globus Compute Action Provider.

The 'results' field contains a list of objects, each containing a 'task_id' field and an 'output' field. The 'task_id' field identifies the task submitted, and the 'output' field contains the result from that run. In the future, more information about the task execution will be added to this object as additional fields. (A list of all the ‘output’ fields from the 'results' dict is the same as what is in the 'result' field)

Example output:

...
"RunResult": {
  "action_id": "tg_44f09e3d-c920-abcd-969a-301b019af1b1",
  "completion_time": "2023-04-14T19:26:33.981517+00:00",
  "creator_id": "urn:globus:auth:identity:12345678-9323-4fe6-93ef-abc6f9ff05d2",
  "details": {
    "result": [
      "Result of task 1",
      "Result of task 2",
    ],
    "results": [
      {
        "output": "Result of task 1",
        "task_id": "c971987e-643b-48ab-af6f-47411234abcd"
      },
      {
        "output": "Result of task 2",
        "task_id": "abc12345-643b-48ab-af6f-12345beabcde"
      }
    ]
  },
...

Gladier

The Gladier toolkit provides useful tools to simplify and accelerate the development of flows that use Globus Compute. For example, Gladier validates inputs prior to starting a flow and will re-register functions when they are modified. Additionally, it includes capabilities to automatically generate flow definitions.