Validation using Pydantic

We provide Pydantic models which automatically handle the validation of input and output documents upon creation. Both the ActionRequest and ActionStatus classes from the data_types module will produce standardized, informative errors if instantiated with incorrect information. If these objects are created correctly when receiving requests and returning results, the ActionProvider complies with the run/ endpoint specification.

from pydantic import ValidationError

from globus_action_provider_tools.data_types import (

# This will fail since ActionRequest objects minimally require a request_id
# and body
    action_request = ActionRequest()
except ValidationError as ve:
    # prints: [{'loc': ('request_id',), 'msg': 'field required', 'type': 'value_error.missing'}, {'loc': ('body',), 'msg': 'field required', 'type': 'value_error.missing'}]

# This will fail since the ActionStatus document requires a creator_id in
# the form of a Globus ARN
    action_status = ActionStatus(creator_id="ME", details={},
except ValidationError as ve:
    # prints: [{'loc': ('creator_id',), 'msg': 'string does not match regex "^urn:globus:(auth:identity|groups:id):([a-fA-F0-9]{8}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{12})$"', 'type': 'value_error.str.regex', 'ctx': {'pattern': '^urn:globus:(auth:identity|groups:id):([a-fA-F0-9]{8}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{12})$'}}]

# This will succeed and contain fields that default to valid values
action_request = ActionRequest(request_id=1, body={})
assert action_request.monitor_by == []

# Display the ActionRequest JSONSchema


The pydantic validation only happens on instantiation. This means that accessing and modifying fields after instantiation is possible. There are no way to prevent a field from getting set to an incorrect value.

Custom Validation

There is an OpenAPI v3 specification for the Action Provider API available as described above. From this specification, we derive schemas that can be used to test incoming and outgoing messages. These schemas may be used to validate input documents and output documents within the service as follows.

from globus_action_provider_tools.validation import (

# Validating a request
request = ValidationRequest(provider_doc_type='ActionRequest',
result = request_validator.validate(request)

# Or a response:
response = ValidationRequest(provider_doc_type='ActionStatus',
result = response_validator.validate(response)

# get list of errors
errors = result.errors

# or get a single string summarizing all errors
err = result.error_msg

The request and response validation functions both take a ValidationRequest structure which has the name of the document type to be validated against and the data to be validated. At present, the document types supported are ActionRequest and ActionStatus documents as defined above.


There are additional validation helpers available for applications written using the Flask framework. Those are described below in the section describing the entire set of Flask helpers.