AWS SAM local start-api cannot resolve Fn::ImportValue

Question

I have SAM template (post here partially):

AWSTemplateFormatVersion: "2010-09-09"
Transform: "AWS::Serverless-2016-10-31"

Parameters:

  StorageStackName:
    Type: String
    Description: Name of the stack which provisions DynamoDB table and S3 bucket.

Globals:

  Function:
      Runtime: nodejs12.x
      MemorySize: 128
      Timeout: 8
      CodeUri: .
      AutoPublishAlias: latest
      Environment:
        Variables:
          SOURCE_TABLE_NAME:
            Fn::ImportValue:
              Fn::Sub: "${StorageStackName}-SourceTableName"

Command gives me a notification

sam local start-api --debug --parameter-overrides='StorageStackName=storage-dev'

Unable to resolve property SOURCE_TABLE_NAME: OrderedDict([('Fn::ImportValue', OrderedDict([('Fn::Sub', '${StorageStackName}-SourceTableName')]))]). Leaving as is.

I tried to remove Sub (no luck):

SOURCE_TABLE_NAME:
  Fn::ImportValue: "storage-dev-SourceTableName"

The template works on the server, so Fn::ImportValue supported. So my question is Fn::ImportValue supported in local invocation at all?

I am made sure I use same credentials (profile) for local SAM as the one where I have storage-dev stack. Any way I can recheck it again to make sure even more?

score 2 · Answer 1 · answered Feb 17 '22 at 19:34

It is a SAM bug that I hope gets fixed soon also. For now, I created a workaround. It is a bash file that gets the exported output value from another stack and passes it as an env variable during invocation, so it will be overwritten.

Just substitute the EXPORTED_VARIABLE_NAME and S3_BUCKET_NAME for your actual names and you are good to go.

Run it like so: ./sam_local_invoke.sh

#!/bin/bash

# The exported variable name from another stack (change it with your variable name)
EXPORTED_VARIABLE_NAME=BotsDataBucketSAM

# Get it as the name of the parameter that we want to overwrite
S3_BUCKET_NAME=$(aws cloudformation list-exports --query "Exports[?Name=='$EXPORTED_VARIABLE_NAME'].Value" --output text | cat)

ENV_OVERWRITES=$(cat <<EOT
{
  "Parameters": {
    "S3_BUCKET_NAME": "$S3_BUCKET_NAME"
  }
}
EOT
)

echo ${ENV_OVERWRITES} > env.json

sam local invoke --env-vars env.json

score 0 · Answer 2 · answered Apr 09 '20 at 20:33

0

It looks like as of this post it is not supported. The last PR I could find only included !Sub and !If. Looks like they will have to be passed in as parameters or env variables while the sam cli matures.

answered Apr 09 '20 at 20:33

wattry

936
10
22

AWS SAM local start-api cannot resolve Fn::ImportValue

2 Answers2