How to read invalid JSON format amazon firehose - json

Question

I've got this most horrible scenario in where i want to read the files that kinesis firehose creates on our S3.
Kinesis firehose creates files that don't have every json object on a new line, but simply a json object concatenated file.
{"param1":"value1","param2":numericvalue2,"param3":"nested {bracket}"}{"param1":"value1","param2":numericvalue2,"param3":"nested {bracket}"}{"param1":"value1","param2":numericvalue2,"param3":"nested {bracket}"}
Now is this a scenario not supported by normal JSON.parse and i have tried working with following regex: .scan(/({((\".?\":.?)*?)})/)
But the scan only works in scenario's without nested brackets it seems.
Does anybody know an working/better/more elegant way to solve this problem?

Answer 1

The one in the initial anwser is for unquoted jsons which happens some times. this one:
({((\\?\".*?\\?\")*?)})
Works for quoted jsons and unquoted jsons
Besides this improved it a bit, to keep it simpler.. as you can have integer and normal values.. anything within string literals will be ignored due too the double capturing group.
https://regex101.com/r/kPSc0i/1

Answer 2

Modify the input to be one large JSON array, then parse that:
input = File.read("input.json")
json = "[#{input.rstrip.gsub(/\}\s*\{/, '},{')}]"
data = JSON.parse(json)
You might want to combine the first two to save some memory:
json = "[#{File.read('input.json').rstrip.gsub(/\}\s*\{/, '},{')}]"
data = JSON.parse(json)
This assumes that } followed by some whitespace followed by { never occurs inside a key or value in your JSON encoded data.

Answer 3

As you concluded in your most recent comment, the put_records_batch in firehose requires you to manually put delimiters in your records to be easily parsed by the consumers. You can add a new line or some special character that is solely used for parsing, % for example, which should never be used in your payload.
Other option would be sending record by record. This would be only viable if your use case does not require high throughput. For that you may loop on every record and load as a stringified data blob. If done in Python, we would have a dictionary "records" having all our json objects.
import json
def send_to_firehose(records):
firehose_client = boto3.client('firehose')
for record in records:
data = json.dumps(record)
firehose_client.put_record(DeliveryStreamName=<your stream>,
Record={
'Data': data
}
)
Firehose by default buffers the data before sending it to your bucket and it should end up with something like this. This will be easy to parse and load in memory in your preferred data structure.
[
{
"metadata": {
"schema_id": "4096"
},
"payload": {
"zaza": 12,
"price": 20,
"message": "Testing sendnig the data in message attribute",
"source": "coming routing to firehose"
}
},
{
"metadata": {
"schema_id": "4096"
},
"payload": {
"zaza": 12,
"price": 20,
"message": "Testing sendnig the data in message attribute",
"source": "coming routing to firehose"
}
}
]