Step Function Key Error?

Question

Hello

I am pulling  values from a dictionary provided as a payload to a Lambda Function and it runs successfully. These are known keys and I printed out the dictionary and checked that it's type is a dictionary. When I execute using the Step Function I am receiving the below key error. If I remove that key then the function throws an error on the next key I am using. 
{
  "errorMessage": "'PROC'",
  "errorType": "KeyError",
  "requestId": "bec5fb2a-5892-4b62-94be-d01a5b7cfa24",
  "stackTrace": [
    "  File "/var/task/lambda_function.py", line 63, in lambda_handler
    PROCNAME = output['PROC']
"
  ]
}

Here is the payload from the first function that is then used by the function that is erroring.
"Payload": {
    "AWSDT": "2024-03-07 06:21:00",
    "DATALOADCONFIGID": 1,
    "PROC": "Info.usp_Load_F7",
    "TABLENAME": "Info.F7",
    "FILENAME": "F7_202403070621.csv"
  }

Here is my python code section that pulls from the dict and loads into variables.
output = json.loads(dump_info)
    print(output)
    jdata_type = type(output)
    print(jdata_type)
    BATCHTIME = output['AWSDT']
    CONFIGID = output['DATALOADCONFIGID']
    PROCNAME = output['PROC']
    TABLENAME = output['TABLENAME']
    KEYNAME = output['FILENAME']
    
    logger.info('Variables loaded')
    logger.info('Values used {},{},{},{},{},'.format(PROCNAME,CONFIGID,TABLENAME,KEYNAME,BATCHTIME))

Can anyone tell me why this is happening and how to fix it?

Answer

It looks like the error you're encountering is a `KeyError`, which means the key you're trying to access in the dictionary doesn't exist. Based on the error message, it seems that `PROC` is missing from the dictionary output. This could happen if the dictionary doesn't contain the key `PROC` for some reason.

To troubleshoot, you can add some additional logging to check the keys present in the output dictionary before trying to access them. For example:
```python
output = json.loads(dump_info)
print(output)
jdata_type = type(output)
print(jdata_type)

# Check if the keys exist in the dictionary
if 'AWSDT' in output:
    BATCHTIME = output['AWSDT']
else:
    logger.error('Key AWSDT not found in dictionary')

if 'DATALOADCONFIGID' in output:
    CONFIGID = output['DATALOADCONFIGID']
else:
    logger.error('Key DATALOADCONFIGID not found in dictionary')

if 'PROC' in output:
    PROCNAME = output['PROC']
else:
    logger.error('Key PROC not found in dictionary')

if 'TABLENAME' in output:
    TABLENAME = output['TABLENAME']
else:
    logger.error('Key TABLENAME not found in dictionary')

if 'FILENAME' in output:
    KEYNAME = output['FILENAME']
else:
    logger.error('Key FILENAME not found in dictionary')

logger.info('Variables loaded')
logger.info('Values used {},{},{},{},{},'.format(PROCNAME, CONFIGID, TABLENAME, KEYNAME, BATCHTIME))
```

Step Function Key Error?

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