how can i retrieve value in JSON string in lambda python3

Question

I'm developing an AWS lambda function that is triggered from an event bridge and then putting another event using python but struggling to retrieve a value from a variable in the Json string

below is the code

import json, boto3

client = boto3.client('events')

def lambda_handler(event, context):

testV2_dict={  
 "K1" : event['e1'] ,
"K2" : event['e2'] 
}

#converting python to json as (put_event - Details) section is expecting json
testV2=json.dumps(testV2_dict)

response = client.put_events(
         Entries=
          [
            {
             "DetailType": "test",
             "Source": "test",
             "Detail": "{ \"testK\": \"testV\",\"testK2\": \""+ testV2 +"\" }"
           }
          ]
        )

tried to add Details on different ways, "Detail": "{ \"testK\": \"testV\",\"testK2\": \""+ testV2 +"\" }" and still getting error as Malformated Details and if i deleted the ++, I'm getting word testV2 itself not the value from the above

How can I retrieve the value of testV2 in the Details inside the event?

Tim Roberts · Accepted Answer · 2022-07-05 18:36:21Z

2

You don't have enough escaping in there. If testV2 is supposed to be a JSON string emebedded in a JSON string embedded in as JSON string, then you need more string escapes. I would let json.dumps handle that:

import json
event = {'e1': 99, 'e2': 101}

testV2_dict={  
 "K1" : event['e1'] ,
 "K2" : event['e2'] 
}

testV2=json.dumps(testV2_dict)

detail = {
    "testK": "testV",
    "testK2": testV2
}

Entries= [
    {
     "DetailType": "test",
     "Source": "test",
     "Detail": json.dumps(detail),
   }
]

print(Entries)

Output:

[{'DetailType': 'test', 'Source': 'test', 'Detail': '{"testK": "testV", "testK2": "{\\"K1\\": 99, \\"K2\\": 101}"}'}]

answered Jul 5, 2022 at 18:36

Tim Roberts

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Comments

saikat sadhukha · Accepted Answer · 2022-07-06 05:58:05Z

-1

I don't think you need to do any thing the output of boto3 client has always been in JSON string.

edited Jul 6, 2022 at 5:58

answered Jul 6, 2022 at 5:56

saikat sadhukha

11 bronze badge

1 Comment

Tim Roberts Over a year ago

You missed the point. The nested content is also an embedded JSON string, and it was not formatted correctly.

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