Aws-cli: AttributeError: 'NoneType' object has no attribute 'items' on malformed CloudFormation

[jghaines]

On malformed CloudFormation, the CLI gives some pretty undecipherable output.

$ aws --version
aws-cli/1.11.24 Python/2.7.10 Darwin/16.1.0 botocore/1.4.81

In a directory containing:

ServerlessTest.zip (zip of this lambda source)
and
example.yaml

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Resources:
TestFunction:
  Type: AWS::Serverless::Function
  Properties:
    Handler: index.handler
    Runtime: nodejs4.3
    Environment:
      Variables: 
        S3_BUCKET: _my-bucket_

Note that "TestFunction" should be indented, but isn't.

I ran the following command

$ aws cloudformation package --template-file example.yaml --output-template-file serverless-output.yaml --s3-bucket _my-bucket_

This gives the unfriendly output:
'NoneType' object has no attribute 'items'

With --debug added, this is narrowed down to:

Traceback (most recent call last):
  File "/Library/Python/2.7/site-packages/awscli/clidriver.py", line 197, in main
    return command_table[parsed_args.command](remaining, parsed_args)
  File "/Library/Python/2.7/site-packages/awscli/clidriver.py", line 333, in __call__
    return command_table[parsed_args.operation](remaining, parsed_globals)
  File "/Library/Python/2.7/site-packages/awscli/customizations/commands.py", line 187, in __call__
    return self._run_main(parsed_args, parsed_globals)
  File "/Library/Python/2.7/site-packages/awscli/customizations/cloudformation/package.py", line 125, in _run_main
    exported_str = self._export(template_path)
  File "/Library/Python/2.7/site-packages/awscli/customizations/cloudformation/package.py", line 141, in _export
    exported_template = template.export()
  File "/Library/Python/2.7/site-packages/awscli/customizations/cloudformation/artifact_exporter.py", line 399, in export
    for resource_id, resource in self.template_dict["Resources"].items():
AttributeError: 'NoneType' object has no attribute 'items'
2016-12-04 16:03:57,035 - MainThread - awscli.clidriver - DEBUG - Exiting with rc 255

'NoneType' object has no attribute 'items'

[kyleknap]

Makes sense. We will look into improving the error message on malformed cloudformation templates.

[Nalha]

Had a similar error message when I left a resource without anything in it.

'NoneType' object has no attribute 'get'

[concon121]

Had the same problem:

'NoneType' object has no attribute 'items'

Resolution was to fix indentation on a resource. Thanks for the help!

[ciryon]

Same here, it would be nice with a better error message.

[suhaibchishti]

Please fix the error, its very misleading