Unable to trigger AWS Lambda by upload to AWS S3

Question

I am trying to build a Kibana dashboard fed with twitter data collected via AWS Kinesis firehose where data passes into an S3 bucket which triggers a Lambda function which passes the data to AWS Elastic Search and then to Kibana. I am following this blog https://aws.amazon.com/blogs/big-data/building-a-near-real-time-discovery-platform-with-aws/

The data is loading into the S3 bucket correctly but it never arrives in Kibana, I believe this is because the Lambda function is not being triggered by events in S3 as I would have hoped (there are no invocations or logs). I think this is because I have not set permissions properly. The Lambda function can be invoked manually by the test event.

On the Lambda function page I chose an existing role which I called lambda_s3_exec_role which has the AWSLambdaExecute policy attached to it but I feel I'm missing something else more specific to S3. I have been unable to follow this line in the blog in the create lambda function section because I do not recognise those options:

"10. Choose lambda_s3_exec_role (if this value does not exist, choose Create new role S3 execution role)."

Can anyone help me create the appropriate role/policy for the Lambda function, or spot what the problem may be?

From view permissions on the Lambda function I currently have:

FUNCTION POLICY

{
  "Version": "2012-10-17",
  "Id": "default",
  "Statement": [
    {
      "Sid": "****",
      "Effect": "Allow",
      "Principal": {
        "Service": "s3.amazonaws.com"
      },
      "Action": "lambda:InvokeFunction",
      "Resource": "****",
      "Condition": {
        "ArnLike": {
          "AWS:SourceArn": "arn:aws:s3:::****"
        }
      }
    }
  ]
}

EXECUTION ROLE

{
  "roleName": "lambda_s3_exec_role",
  "policies": [
    {
      "document": {
        "Version": "2012-10-17",
        "Statement": [
          {
            "Effect": "Allow",
            "Action": [
              "logs:*"
            ],
            "Resource": "arn:aws:logs:*:*:*"
          },
          {
            "Effect": "Allow",
            "Action": [
              "s3:GetObject",
              "s3:PutObject"
            ],
            "Resource": "arn:aws:s3:::*"
          }
        ]
      },
      "name": "AWSLambdaExecute",
      "id": "****",
      "type": "managed",
      "arn": "arn:aws:iam::aws:policy/AWSLambdaExecute"
    }
  ]
}

Answer 1

The permissions you have listed look OK so I am going to try provide some steps that might help find the issue as it is difficult to understand specifically where your issue might be.

1. Does the execution role have the trust relationship with a trusted entity of lambda.amazonaws.com
2. Does your event prefix match the prefix in firehose. In the tutorial they are both twitter/raw-data/ . If firehose is writing to a path that isn't the event prefix then the event won't be invoked.
3. Does the lambda trigger any errors when you manually invoke it
4. Does the lambda write to the logs when you manually invoke it
5. Test the lambda using dummy data (example data below)

CLI

aws lambda invoke \
--invocation-type RequestResponse \
--function-name helloworld \
--region region \
--log-type Tail \
--payload file://dummy_event.json \
--profile adminuser \
outputfile.txt 

Example data

source

dummy_event.json

{
   "Records":[  
      {  
         "eventVersion":"2.0",
         "eventSource":"aws:s3",
         "awsRegion":"us-west-2",
         "eventTime":"1970-01-01T00:00:00.000Z",
         "eventName":"ObjectCreated:Put",
         "userIdentity":{  
            "principalId":"AIDAJDPLRKLG7UEXAMPLE"
         },
         "requestParameters":{  
            "sourceIPAddress":"127.0.0.1"
         },
         "responseElements":{  
            "x-amz-request-id":"C3D13FE58DE4C810",
            "x-amz-id-2":"FMyUVURIY8/IgAtTv8xRjskZQpcIZ9KG4V5Wp6S7S/JRWeUWerMUE5JgHvANOjpD"
         },
         "s3":{  
            "s3SchemaVersion":"1.0",
            "configurationId":"testConfigRule",
            "bucket":{  
               "name":"sourcebucket",
               "ownerIdentity":{  
                  "principalId":"A3NL1KOZZKExample"
               },
               "arn":"arn:aws:s3:::sourcebucket"
            },
            "object":{  
               "key":"HappyFace.jpg",
               "size":1024,
               "eTag":"d41d8cd98f00b204e9800998ecf8427e",
               "versionId":"096fKKXTRTtl3on89fVO.nfljtsv6qko"
            }
         }
      }
   ]
}