AWS SAM Multiple Functions with same Inline Policy

Question

In the AWS SAM .yaml template I can declare an inline policy for each lambda function like so:

AWSTemplateFormatVersion: '2010-09-09'
Transform: 'AWS::Serverless-2016-10-31'
Resources:
  MyFunction:
    Type: 'AWS::Serverless::Function'
    Properties:
      Handler: index.handler
      Runtime: nodejs8.10
      CodeUri: 's3://my-bucket/function.zip'
      Policies:
      - Statement:
        - Sid: SSMDescribeParametersPolicy
          Effect: Allow
          Action:
          - ssm:DescribeParameters
          Resource: '*'
        - Sid: SSMGetParameterPolicy
          Effect: Allow
          Action:
          - ssm:GetParameters
          - ssm:GetParameter
          Resource: '*'

However if I want multiple functions to share the same inline policy document, do we declare it in the 'Globals' section of the template?

So far the documentation leads me to believe that the cleanest way to do this would be creating a role with the attached policies and simply declaring the role to each function instead like so:

AWSTemplateFormatVersion: '2010-09-09'
Transform: 'AWS::Serverless-2016-10-31'
Resources: 
  MyFunction:
    Type: 'AWS::Serverless::Function' 
    Properties:
      Handler: index.handler
      Runtime: nodejs8.10
      CodeUri: 's3://my-bucket/function.zip' 
      Role: arn:aws:iam::111111111111:role/SAMPolicy

Is there a way to declare an inline policy within the template and simply reference it on each function instead?

Answer 1

An inline policy can’t be referenced and reused. However, you can create and reference an AWS Managed Policy or a SAM policy template instead of an inline policy.

If you want to use a reusable custom policy, you will have to create a Customer Managed Policy and attach to the Lambda functions via the Role property.

Answer 2

If I want multiple functions to share the same inline policy document, do we declare it in the 'Globals' section of the template? Yes. Here is an example:

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

Globals:
  Function:
    Policies:
      - Statement:
          - Sid: SSMDescribeParametersPolicy
            Effect: Allow
            Action:
              - ssm:DescribeParameters
            Resource: '*'
          - Sid: SSMGetParameterPolicy
            Effect: Allow
            Action:
              - ssm:GetParameters
              - ssm:GetParameter
            Resource: '*'

Resources:
  MyFunction:
    Type: 'AWS::Serverless::Function'
    Properties:
      Handler: index.handler
      Runtime: nodejs8.10
      CodeUri: 's3://my-bucket/function.zip'
  MyOtherFunction:
    Type: 'AWS::Serverless::Function'
    Properties:
      Handler: index.handler
      Runtime: nodejs8.10
      CodeUri: 's3://my-bucket/other-function.zip'