Basic AWS SAM template to run NodeJs Lambdas locally: sam local invoke -t sam_template.yml -e test/fixtures/s3-to-lambda-put-event.json

aws_sam_template.yml

AWSTemplateFormatVersion : '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Resources:
  LambdaFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: index.handler
      Runtime: nodejs8.10
      MemorySize: 128
      Timeout: 15
      Environment:
        Variables:
          LOG_LEVEL: "debug"

s3-to-lambda-put-event.json

{
    "Records": [
        {
            "eventVersion": "2.1",
            "eventSource": "aws:s3",
            "awsRegion": "ap-southeast-2",
            "eventTime": "2019-02-25T02:25:09.091Z",
            "eventName": "ObjectCreated:Put",
            "userIdentity": {
                "principalId": "AWS:NAH"
            },
            "requestParameters": {
                "sourceIPAddress": "666.84.43.666"
            },
            "responseElements": {
                "x-amz-request-id": "PUFT",
                "x-amz-id-2": "lalaland"
            },
            "s3": {
                "s3SchemaVersion": "1.0",
                "configurationId": "666-666",
                "bucket": {
                    "name": "company-dev-project-app",
                    "ownerIdentity": {
                        "principalId": "MEMYMINE"
                    },
                    "arn": "arn:aws:s3:::company-dev-project-app"
                },
                "object": {
                    "key": "my_folder/excellent_file.csv",
                    "size": 1310,
                    "eTag": "aabbcc",
                    "sequencer": "00112233"
                }
            }
        }
    ]
}