Sad example of how verbose and messy Amplify and Cloudformation template files are. This 300 lines long piece of code is just an example of a descriptor for a tiny Lambda function listening to messages in SQS queue. Also keep in mind source code of the lambda itself on top of this as well as several other small config files.

amplify-lambda-sqs-handler-sample.json

{
  "AWSTemplateFormatVersion": "2010-09-09",
  "Description": "Lambda Function resource stack creation using Amplify CLI",
  "Parameters": {
    "CloudWatchRule": {
      "Type": "String",
      "Default": "NONE",
      "Description": " Schedule Expression"
    },
    "env": {
      "Type": "String"
    },
    "someparam": {
      "Type": "String",
      "Default": "someparamdefault"
    },
    "myqueueName": {
      "Type": "String",
      "Default": "myqueueName"
    },
    "deploymentBucketName": {
      "Type": "String"
    },
    "s3Key": {
      "Type": "String"
    },
    "myqueueArn": {
      "Type": "String",
      "Default": "myqueueArn"
    }
  },
  "Conditions": {
    "ShouldNotCreateEnvResources": {
      "Fn::Equals": [
        {
          "Ref": "env"
        },
        "NONE"
      ]
    }
  },
  "Resources": {
    "LambdaFunction": {
      "Type": "AWS::Lambda::Function",
      "Metadata": {
        "aws:asset:path": "./src",
        "aws:asset:property": "Code"
      },
      "Properties": {
        "Handler": "myLambdaModule.handler",
        "FunctionName": {
          "Fn::If": [
            "ShouldNotCreateEnvResources",
            "myqueueName",
            {
              "Fn::Join": [
                "",
                [
                  "myqueueName",
                  "-",
                  {
                    "Ref": "env"
                  }
                ]
              ]
            }
          ]
        },
        "Environment": {
          "Variables": {
            "ENV": {
              "Ref": "env"
            },
            "REGION": {
              "Ref": "AWS::Region"
            },
            "MY_LAMBDA_PARAM_ENV_VARIABLE": {
              "Ref": "someparam"
            }
          }
        },
        "Role": {
          "Fn::GetAtt": [
            "LambdaExecutionRole",
            "Arn"
          ]
        },
        "Runtime": "nodejs14.x",
        "MemorySize": 256,
        "Layers": [],
        "Code": {
          "S3Bucket": {
            "Ref": "deploymentBucketName"
          },
          "S3Key": {
            "Ref": "s3Key"
          }
        },
        "Timeout": "240"
      }
    },
    "LambdaExecutionRole": {
      "Type": "AWS::IAM::Role",
      "Properties": {
        "RoleName": {
          "Fn::If": [
            "ShouldNotCreateEnvResources",
            "lambadSqsHandlerRoleName2c24c2",
            {
              "Fn::Join": [
                "",
                [
                  "lambadSqsHandlerRoleName2c24c2",
                  "-",
                  {
                    "Ref": "env"
                  }
                ]
              ]
            }
          ]
        },
        "AssumeRolePolicyDocument": {
          "Version": "2012-10-17",
          "Statement": [
            {
              "Effect": "Allow",
              "Principal": {
                "Service": [
                  "lambda.amazonaws.com"
                ]
              },
              "Action": [
                "sts:AssumeRole"
              ]
            }
          ]
        }
      }
    },
    "LambdaFunctionEventSourceMapping": {
      "DependsOn": [
        "lambdaexecutionpolicy"
      ],
      "Type": "AWS::Lambda::EventSourceMapping",
      "Properties": {
        "EventSourceArn": {
          "Ref": "myqueueArn"
        },
        "FunctionName": {
          "Ref": "LambdaFunction"
        },
        "BatchSize": 1
      }
    },
    "lambdaexecutionpolicy": {
      "DependsOn": [
        "LambdaExecutionRole"
      ],
      "Type": "AWS::IAM::Policy",
      "Properties": {
        "PolicyName": "lambda-execution-policy",
        "Roles": [
          {
            "Ref": "LambdaExecutionRole"
          }
        ],
        "PolicyDocument": {
          "Version": "2012-10-17",
          "Statement": [
            {
              "Effect": "Allow",
              "Action": [
                "logs:CreateLogGroup",
                "logs:CreateLogStream",
                "logs:PutLogEvents"
              ],
              "Resource": {
                "Fn::Sub": [
                  "arn:aws:logs:${region}:${account}:log-group:/aws/lambda/${lambda}:log-stream:*",
                  {
                    "region": {
                      "Ref": "AWS::Region"
                    },
                    "account": {
                      "Ref": "AWS::AccountId"
                    },
                    "lambda": {
                      "Ref": "LambdaFunction"
                    }
                  }
                ]
              }
            },
            {
              "Effect": "Allow",
              "Action": [
                "sqs:ReceiveMessage",
                "sqs:DeleteMessage",
                "sqs:GetQueueAttributes"
              ],
              "Resource": "*"
            },
            {
              "Effect": "Allow",
              "Action": [
                "secretsmanager:CreateSecret",
                "secretsmanager:Describe*",
                "secretsmanager:Get*",
                "secretsmanager:List*"
              ],
              "Resource": {
                "Fn::Sub": [
                  "arn:aws:secretsmanager:${region}:${account}:secret:*",
                  {
                    "region": {
                      "Ref": "AWS::Region"
                    },
                    "account": {
                      "Ref": "AWS::AccountId"
                    },
                    "lambda": {
                      "Ref": "LambdaFunction"
                    }
                  }
                ]
              }
            }
          ]
        }
      }
    },
    "AmplifyResourcesPolicy": {
      "DependsOn": [
        "LambdaExecutionRole"
      ],
      "Type": "AWS::IAM::Policy",
      "Properties": {
        "PolicyName": "amplify-lambda-execution-policy",
        "Roles": [
          {
            "Ref": "LambdaExecutionRole"
          }
        ],
        "PolicyDocument": {
          "Version": "2012-10-17",
          "Statement": [
            {
              "Effect": "Allow",
              "Action": [
                "dynamodb:Put*",
                "dynamodb:Create*",
                "dynamodb:BatchWriteItem",
                "dynamodb:Get*",
                "dynamodb:BatchGetItem",
                "dynamodb:List*",
                "dynamodb:Describe*",
                "dynamodb:Scan",
                "dynamodb:Query",
                "dynamodb:Update*",
                "dynamodb:RestoreTable*",
                "dynamodb:Delete*"
              ],
              "Resource": [
                {
                  "Ref": "storagemyprojectdbArn"
                },
                {
                  "Fn::Join": [
                    "/",
                    [
                      {
                        "Ref": "storagemyprojectdbArn"
                      },
                      "index/*"
                    ]
                  ]
                }
              ]
            }
          ]
        }
      }
    }
  },
  "Outputs": {
    "Name": {
      "Value": {
        "Ref": "LambdaFunction"
      }
    },
    "Arn": {
      "Value": {
        "Fn::GetAtt": [
          "LambdaFunction",
          "Arn"
        ]
      }
    },
    "Region": {
      "Value": {
        "Ref": "AWS::Region"
      }
    },
    "LambdaExecutionRole": {
      "Value": {
        "Ref": "LambdaExecutionRole"
      }
    }
  }
}