Error when testing Python lambda in AWS console

Question

I'm trying to implment a lambda using python. I'm getting the error below when testing it in the aws console.

lambda_handler

from datetime import datetime
import json
# import os
import boto3

DATA_ENGINEERING_BUCKET = "kinesis-archive"
RATE_PATH = "archive/rates"
s3_client = boto3.client('s3')

def lambda_handler(event, context):
    for record in event["Records"]:
        print(f"Event: {record['eventName']}/{record['eventID']}")
        table_arn, _ = record["eventSourceARN"].split("/stream")
        if record["PK"].startswith('CLASS'):
            key = '#'.join([record['PK'], record['SK']])
            s3_client.put_object(
                Body = json.dumps(record),
                Bucket = DATA_ENGINEERING_BUCKET,
                Key= '/'.join([RATE_PATH, key])
            )
    return { "statusCode": 200, "body": "OK" }

test input

{
  "Records": [
    {
      "kinesis": {
        "partitionKey": "partitionKey-03",
        "kinesisSchemaVersion": "1.0",
        "data": "SGVsbG8sIHRoaXMgaXMgYSB0ZXN0IDEyMy4=",
        "sequenceNumber": "49545115243490985018280067714973144582180062593244200961",
        "approximateArrivalTimestamp": 1428537600
      },
      "eventSource": "aws:kinesis",
      "eventID": "shardId-000000000000:49545115243490985018280067714973144582180062593244200961",
      "invokeIdentityArn": "arn:aws:iam::EXAMPLE",
      "eventVersion": "1.0",
      "eventName": "aws:kinesis:record",
      "eventSourceARN": "arn:aws:kinesis:EXAMPLE",
      "awsRegion": "us-east-1",
      "PK": "CLASS#CA",
      "SK": "1"
    }
  ]
}

error

Response
{
  "errorMessage": "not enough values to unpack (expected 2, got 1)",
  "errorType": "ValueError",
  "requestId": "d998cbd1-d537-4f24-8e30-65f7c350cf07",
  "stackTrace": [
    "  File \"/var/task/lambda_function.py\", line 17, in lambda_handler\n    table_arn, _ = record[\"eventSourceARN\"].split(\"/stream\")\n"
  ]
}

Function Logs
START RequestId: d998cbd1-d537-4f24-8e30-65f7c350cf07 Version: $LATEST
Event: aws:kinesis:record/shardId-000000000000:49545115243490985018280067714973144582180062593244200961
[ERROR] ValueError: not enough values to unpack (expected 2, got 1)
Traceback (most recent call last):
  File "/var/task/lambda_function.py", line 17, in lambda_handler
    table_arn, _ = record["eventSourceARN"].split("/stream")END RequestId: d998cbd1-d537-4f24-8e30-65f7c350cf07
REPORT RequestId: d998cbd1-d537-4f24-8e30-65f7c350cf07  Duration: 1.41 ms   Billed Duration: 2 ms   Memory Size: 128 MB Max Memory Used: 67 MB  
XRAY TraceId: 1-614ccd64-284f0f0f425eb6004bb5e1d0   SegmentId: 1fbd881072d3ec61 Sampled: true

Request ID
d998cbd1-d537-4f24-8e30-65f7c350cf07

You left out the error message.

Mark B
– Mark B

2021-09-23 19:02:56 +00:00
Commented Sep 23, 2021 at 19:02 — Mark B
– Mark B, Commented Sep 23, 2021 at 19:02
@MarkB Thanks I added it

Antarr Byrd
– Antarr Byrd

2021-09-23 19:05:40 +00:00
Commented Sep 23, 2021 at 19:05 — Antarr Byrd
– Antarr Byrd, Commented Sep 23, 2021 at 19:05
@AntarrByrd - See my answer :-)

balderman
– balderman

2021-09-23 19:07:20 +00:00
Commented Sep 23, 2021 at 19:07 — balderman
– balderman, Commented Sep 23, 2021 at 19:07

balderman · Accepted Answer · 2021-09-23 19:06:53Z

2

The error is below

d = {"eventSourceARN": "arn:aws:kinesis:EXAMPLE"}
table_arn, _ = d["eventSourceARN"].split("/stream")

Error:

ValueError: not enough values to unpack (expected 2, got 1)

It looks like you assume that the split will return 2 elements. But it is not true.

the solution is not to assume how many elements to return - check in runtime how many elements you have in the list that is returned by split

answered Sep 23, 2021 at 19:06

balderman

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1 Comment

balderman Over a year ago

it means that you did not change the lambda code ... Start by testing in on your local env. (laptop,etc) and pass the payload you are expected. Once it is stable - upload it to AWS.

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