[SOLVED] Is it possible to use SSM parameters in environment variables for a lambda?

Is it possible to use SSM parameters in environment variables for a lambda?

I know in Cloudformation you can create Parameters using SSM, but I really want to know if you can use SSM in environment variables for a lambda. I know I can put the SSM paths and use the sdk in the code to get those values, but maybe there is a way to make that automatically without fetching values from code.

Thanks

Solution

You can directly fetch the values within CloudFormation from parameter store and pass it as an environment variable to the lambda using dynamic reference.

For example:

  ServerlessTestLambda:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: src
      Handler: test-env-var.handler
      Role: !GetAtt BasicLambdaRole.Arn
      Environment:
        Variables:
          ParamStoreVar: "{{resolve:ssm:/test/ssmparam:3}}"
      Events:
        LambdaSchedule:
          Type: Schedule
          Properties:
            Schedule: rate(3 minutes)

This is the lambda I created to test, and as you can see the value of the key would be replaced for the environment variable ParamStoreVar

Note - You cannot replace ssm securestring in the environment variable for obvious security reasons.

For more information: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/dynamic-references.html