Stack error AttributeError: 'collections.OrderedDict' object has no attribute 'startswith' for cdk generated template

[stmfcgcg]

Description:

I have large project made up of 50 lambas in nested stacks. I have generated the template.yml from a cdk project (see attached template.yml). When I run 'sam local start-api' the application does not run and displays a stack trace (see attachment)

Steps to reproduce:

run 'sam local start-api' with the attached template.yml

Observed result:

Traceback (most recent call last):
File "/usr/local/bin/sam", line 8, in
sys.exit(cli())
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/click/core.py", line 829, in call
return self.main(*args, **kwargs)
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/click/core.py", line 782, in main
rv = self.invoke(ctx)
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/click/core.py", line 1259, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/click/core.py", line 1259, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/click/core.py", line 1066, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/click/core.py", line 610, in invoke
return callback(*args, **kwargs)
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/click/decorators.py", line 73, in new_func
return ctx.invoke(f, obj, *args, **kwargs)
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/click/core.py", line 610, in invoke
return callback(*args, **kwargs)
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/samcli/lib/telemetry/metric.py", line 153, in wrapped
raise exception # pylint: disable=raising-bad-type
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/samcli/lib/telemetry/metric.py", line 122, in wrapped
return_value = func(*args, **kwargs)
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/samcli/lib/utils/version_checker.py", line 42, in wrapped
actual_result = func(*args, **kwargs)
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/samcli/cli/main.py", line 90, in wrapper
return func(*args, **kwargs)
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/samcli/commands/local/start_api/cli.py", line 92, in cli
do_cli(
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/samcli/commands/local/start_api/cli.py", line 161, in do_cli
with InvokeContext(
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/samcli/commands/local/cli_common/invoke_context.py", line 190, in enter
self._stacks = self._get_stacks()
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/samcli/commands/local/cli_common/invoke_context.py", line 403, in _get_stacks
stacks, _ = SamLocalStackProvider.get_stacks(
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/samcli/lib/providers/sam_stack_provider.py", line 230, in get_stacks
current = SamLocalStackProvider(
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/samcli/lib/providers/sam_stack_provider.py", line 64, in init
self._extract_stacks()
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/samcli/lib/providers/sam_stack_provider.py", line 116, in _extract_stacks
stack = SamLocalStackProvider._convert_cfn_stack_resource(
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/samcli/lib/providers/sam_stack_provider.py", line 168, in _convert_cfn_stack_resource
if SamLocalStackProvider.is_remote_url(template_url):
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/samcli/lib/providers/sam_stack_provider.py", line 250, in is_remote_url
return any([url.startswith(prefix) for prefix in ["s3://", "http://", "https://"]])
File "/usr/local/Cellar/aws-sam-cli/1.23.0/libexec/lib/python3.8/site-packages/samcli/lib/providers/sam_stack_provider.py", line 250, in
return any([url.startswith(prefix) for prefix in ["s3://", "http://", "https://"]])
AttributeError: 'collections.OrderedDict' object has no attribute 'startswith'

see attachment for full output with --debug enabled

Expected result:

The API gateway to be running locally

Additional environment details (Ex: Windows, Mac, Amazon Linux etc)

1. OS: Mac Catalina 10.15.7
2. sam --version: 1.23.0
3. AWS region: US-west-2

error.txt
template.yml.txt

[awood45]

We have a new release that may help with this - give it a try: https://aws.amazon.com/blogs/compute/better-together-aws-sam-and-aws-cdk/

[stmfcgcg]

Thanks for the response @awood45
This does get me further, I no longer have that error. Unfortunately I now have a different one

Error: Template does not have any APIs connected to Lambda functions

According to this stackoverflow Q there should be an Events section in template.yml and mine does not have one:

https://stackoverflow.com/questions/50680191/aws-sam-template-does-not-have-any-apis-connected-to-lambda-functions

I do have 40+ lambdas hooked upto the API gateway but none of them are in the root stack, they are all in the nested stacks (the root stack does not inherit for NestedStack, but all the children do)

errors1.txt

[awood45]

Can you possibly share more of the relevant parts of your CDK app definition? It's somewhat difficult to debug from the generated YAML.

[aahung]

From the error message, it looks like a bug in SAM CLI where _convert_cfn_stack_resource() assumes "AWS::CloudFormation::Stack" always have a string TemplateURL`, which is not the case in CDK generated files (caused by unsolvable intrinsic functions):

    Type: AWS::CloudFormation::Stack
    Properties:
      TemplateURL:
        Fn::Join:
          - ""
          - - https://s3.us-west-2.
            - Ref: AWS::URLSuffix
            - /
            - Ref: AssetParameters9877facd27675b5eb22145b6ec47a667610d0acab3d0996baac2b7106d7581ecS3Bucket4DCB2A62
            - /
            - Fn::Select:
                - 0
                - Fn::Split:
                    - "||"
                    - Ref: AssetParameters9877facd27675b5eb22145b6ec47a667610d0acab3d0996baac2b7106d7581ecS3VersionKey51E61DF0
            - Fn::Select:
                - 1
                - Fn::Split:
                    - "||"
                    - Ref: AssetParameters9877facd27675b5eb22145b6ec47a667610d0acab3d0996baac2b7106d7581ecS3VersionKey51E61DF0
                    - 

[aahung]

If the templates is generated from CDK, you can use sam-beta-cdk to run sam-beta-cdk build and sam-beta-cdk local invoke/start-api/start-lambda directly on the CDK app.