Translator Wrapper defaults to `us-east-1` for SAR applications

Description

sam build does not replace the region properly when transforming the template. The region is defined as us-east-1 and that is the region used on transform in SamTranslatorWrapper regardless of AWS_DEFAULT_REGION, .aws/config, or region flag values

Steps to reproduce

Reproduction repo: https://github.com/NathanYocum/sam-sar-bug (requires changing account id’s and an s3 bucket in us-east-1 and us-east-2).

1. pip install aws-sam-cli==0.53.0
2. Publish a SAR application to us-east-1 and us-east-2
3. Build or deploy a template that uses the SAR application with the following for example:

# template.yml
AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Mappings:
  SAMBuildTest:
    us-east-1:
      # Replace AccountId
      ApplicationId: arn:aws:serverlessrepo:us-east-1:854484851566:applications/sam-build-test
      SemanticVersion: 0.0.2
    us-east-2:
      # Replace AccountId
      ApplicationId: arn:aws:serverlessrepo:us-east-2:854484851566:applications/sam-build-test
      SemanticVersion: 0.0.2
Resources:
  SAMBuildSAR:
    Type: AWS::Serverless::Application
    Properties:
      Location:
        ApplicationId: !FindInMap [ SAMBuildTest, !Ref AWS::Region, ApplicationId ]
        SemanticVersion: !FindInMap [ SAMBuildTest, !Ref AWS::Region, SemanticVersion ]

AWS_DEFAULT_REGION=us-east-1 sam build # passes
AWS_DEFAULT_REGION=us-east-2 sam build # fails
sam build --region us-east-2 # fails

Observed result

Command: AWS_DEFAULT_REGION=us-east-2 sam build --debug

samcli.commands.validate.lib.exceptions.InvalidSamDocumentException: [InvalidResourceException('SAMBuildSAR', 'Application with id arn:aws:serverlessrepo:us-east-1:854484851566:applications/sam-build-test could not be found.')] ('SAMBuildSAR', 'Application with id arn:aws:serverlessrepo:us-east-1:854484851566:applications/sam-build-test could not be found.')

Full output:

Telemetry endpoint configured to be https://aws-serverless-tools-telemetry.us-west-2.amazonaws.com/metrics
'build' command is called
No Parameters detected in the template
Sending Telemetry: {'metrics': [{'commandRun': {'awsProfileProvided': False, 'debugFlagProvided': True, 'region': '', 'commandName': 'sam build', 'duration': 556, 'exitReason': 'InvalidSamDocumentException', 'exitCode': 255, 'requestId': '35a8bf9d-ccd4-4e22-8f8c-79b6a1987a79', 'installationId': 'e7ea7dd6-88c2-49c8-80b5-45f7634ac522', 'sessionId': '31e76f7b-98d6-4bf0-90d8-74962e5c565d', 'executionEnvironment': 'CLI', 'pyversion': '3.7.7', 'samcliVersion': '0.53.0'}}]}
Telemetry response: 200
Traceback (most recent call last):
  File "/usr/local/Cellar/aws-sam-cli/0.53.0/libexec/lib/python3.7/site-packages/samcli/lib/samlib/wrapper.py", line 77, in run_plugins
    parser.parse(template_copy, all_plugins)  # parse() will run all configured plugins
  File "/usr/local/Cellar/aws-sam-cli/0.53.0/libexec/lib/python3.7/site-packages/samcli/lib/samlib/wrapper.py", line 146, in parse
    raise InvalidDocumentException(document_errors)
samtranslator.model.exceptions.InvalidDocumentException: [InvalidResourceException('SAMBuildSAR', 'Application with id arn:aws:serverlessrepo:us-east-1:854484851566:applications/sam-build-test could not be found.')]

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/bin/sam", line 33, in <module>
    sys.exit(load_entry_point('aws-sam-cli==0.53.0', 'console_scripts', 'sam')())
  File "/usr/local/Cellar/aws-sam-cli/0.53.0/libexec/lib/python3.7/site-packages/click/core.py", line 829, in __call__
    return self.main(*args, **kwargs)
  File "/usr/local/Cellar/aws-sam-cli/0.53.0/libexec/lib/python3.7/site-packages/click/core.py", line 782, in main
    rv = self.invoke(ctx)
  File "/usr/local/Cellar/aws-sam-cli/0.53.0/libexec/lib/python3.7/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/0.53.0/libexec/lib/python3.7/site-packages/click/core.py", line 1066, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/local/Cellar/aws-sam-cli/0.53.0/libexec/lib/python3.7/site-packages/click/core.py", line 610, in invoke
    return callback(*args, **kwargs)
  File "/usr/local/Cellar/aws-sam-cli/0.53.0/libexec/lib/python3.7/site-packages/click/decorators.py", line 73, in new_func
    return ctx.invoke(f, obj, *args, **kwargs)
  File "/usr/local/Cellar/aws-sam-cli/0.53.0/libexec/lib/python3.7/site-packages/click/core.py", line 610, in invoke
    return callback(*args, **kwargs)
  File "/usr/local/Cellar/aws-sam-cli/0.53.0/libexec/lib/python3.7/site-packages/samcli/lib/telemetry/metrics.py", line 96, in wrapped
    raise exception  # pylint: disable=raising-bad-type
  File "/usr/local/Cellar/aws-sam-cli/0.53.0/libexec/lib/python3.7/site-packages/samcli/lib/telemetry/metrics.py", line 62, in wrapped
    return_value = func(*args, **kwargs)
  File "/usr/local/Cellar/aws-sam-cli/0.53.0/libexec/lib/python3.7/site-packages/samcli/commands/build/command.py", line 129, in cli
    mode,
  File "/usr/local/Cellar/aws-sam-cli/0.53.0/libexec/lib/python3.7/site-packages/samcli/commands/build/command.py", line 179, in do_cli
    mode=mode,
  File "/usr/local/Cellar/aws-sam-cli/0.53.0/libexec/lib/python3.7/site-packages/samcli/commands/build/build_context.py", line 62, in __enter__
    self._function_provider = SamFunctionProvider(self._template_dict, self._parameter_overrides)
  File "/usr/local/Cellar/aws-sam-cli/0.53.0/libexec/lib/python3.7/site-packages/samcli/lib/providers/sam_function_provider.py", line 40, in __init__
    self.template_dict = SamFunctionProvider.get_template(template_dict, parameter_overrides)
  File "/usr/local/Cellar/aws-sam-cli/0.53.0/libexec/lib/python3.7/site-packages/samcli/lib/providers/sam_base_provider.py", line 126, in get_template
    template_dict = SamTranslatorWrapper(template_dict, parameter_values=parameters_values).run_plugins()
  File "/usr/local/Cellar/aws-sam-cli/0.53.0/libexec/lib/python3.7/site-packages/samcli/lib/samlib/wrapper.py", line 80, in run_plugins
    functools.reduce(lambda message, error: message + " " + str(error), e.causes, str(e))
samcli.commands.validate.lib.exceptions.InvalidSamDocumentException: [InvalidResourceException('SAMBuildSAR', 'Application with id arn:aws:serverlessrepo:us-east-1:854484851566:applications/sam-build-test could not be found.')] ('SAMBuildSAR', 'Application with id arn:aws:serverlessrepo:us-east-1:854484851566:applications/sam-build-test could not be found.')

I was able to fix this by adding

        self.parameter_values["AWS::Region"] = boto3.session.Session().region_name

to https://github.com/awslabs/aws-sam-cli/blob/develop/samcli/lib/samlib/wrapper.py#L40 but I’m sure the region in context is encapsulated somewhere else better for a solution.

Expected result

Build/Deploy succeeds in us-east-2 and other regions aside from us-east-1

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

1. OS: macOS 10.15.5
2. sam --version: 0.53.0 (tried both the pip and brew versions to no success)

[natasha-audrey]

https://github.com/awslabs/serverless-application-model/blob/develop/samtranslator/plugins/application/serverless_app_plugin.py#L129 seems to be where the ApplicationId transformed to us-east-1 is occurring in the on_before_transform.

The dict of params passed into the translator transforms ['SAMBuildTest', {'Ref': 'AWS::Region'}, 'ApplicationId'], ['SAMBuildTest', {'Ref': 'AWS::Region'}, 'SemanticVersion'] into ['SAMBuildTest', 'us-east-1', 'ApplicationId'], ['SAMBuildTest', 'us-east-1', 'SemanticVersion'].

This works fine if I just do aws cloudformation deploy, since I think CF leaves the pseudo params unresolved until deployed, but this currently runs into issues with sam build and sam deploy. It would be ideal to just let CF do the resolution of the pseudo params but if not possible at least using the values from config/flags.

[github-actions[bot]]

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