Confusing errors from client.describe_images - what type is Filters?

from boto3.session import Session
session = Session()
client = session.client(service_name='ec2', region_name='us-west-1')
images = client.describe_images(Filters={'virtualization-type':'hvm'})

Traceback (most recent call last):
  File "C:/Users/Adam/Documents/Git/junkcode/Python/spotprices/gimme.py", line 8, in <module>
    images = client.describe_images(Filters={'virtualization-type':'hvm'})
  File "C:\Users\Adam\Documents\PyEnvs\ec2-venv\lib\site-packages\botocore\client.py", line 269, in _api_call
    return self._make_api_call(operation_name, kwargs)
  File "C:\Users\Adam\Documents\PyEnvs\ec2-venv\lib\site-packages\botocore\client.py", line 310, in _make_api_call
    api_params, operation_model)
  File "C:\Users\Adam\Documents\PyEnvs\ec2-venv\lib\site-packages\botocore\client.py", line 351, in _convert_to_request_dict
    api_params, operation_model)
  File "C:\Users\Adam\Documents\PyEnvs\ec2-venv\lib\site-packages\botocore\validate.py", line 273, in serialize_to_request
    raise ParamValidationError(report=report.generate_report())
botocore.exceptions.ParamValidationError: Parameter validation failed:
Invalid type for parameter Filters, value: {'virtualization-type': 'hvm'}, type: <class 'dict'>, valid types: <class 'list'>, <class 'tuple'>

session = Session()
client = session.client(service_name='ec2', region_name='us-west-1')
images = client.describe_images(Filters=['virtualization-type:hvm',])

Traceback (most recent call last):
  File "C:/Users/Adam/Documents/Git/junkcode/Python/spotprices/gimme.py", line 8, in <module>
    images = client.describe_images(Filters=['virtualization-type:hvm',])
  File "C:\Users\Adam\Documents\PyEnvs\ec2-venv\lib\site-packages\botocore\client.py", line 269, in _api_call
    return self._make_api_call(operation_name, kwargs)
  File "C:\Users\Adam\Documents\PyEnvs\ec2-venv\lib\site-packages\botocore\client.py", line 310, in _make_api_call
    api_params, operation_model)
  File "C:\Users\Adam\Documents\PyEnvs\ec2-venv\lib\site-packages\botocore\client.py", line 351, in _convert_to_request_dict
    api_params, operation_model)
  File "C:\Users\Adam\Documents\PyEnvs\ec2-venv\lib\site-packages\botocore\validate.py", line 273, in serialize_to_request
    raise ParamValidationError(report=report.generate_report())
botocore.exceptions.ParamValidationError: Parameter validation failed:
Invalid type for parameter Filters[0], value: virtualization-type:hvm, type: <class 'str'>, valid types: <class 'dict'>

[JordonPhillips]

The docs here seem to be sufficient to show what should be in the request: http://boto3.readthedocs.io/en/latest/reference/services/ec2.html#EC2.Client.describe_images

I’m not sure how we can improve the error message, which tells you the index of the type that had the issue.

If you still are having issues please feel free to open up another issue and we’ll get back to you.

[mbarrien]

Really, you can’t improve the error message here? You have to know ahead of time to go look at a webpage that isn’t mentioned anywhere, and can’t get it from the error message or the source? All you’re told by the error message above is that it’s expecting a list or tuple, and doesn’t say ANYTHING about what that list is supposed to contain (which also requires an extreme amount of structure). There is a LOT of improvement that can be done to the error message, and saying “We’re not sure how” is disappointing.