CODEWITHSUNDEEP
pythonaws-lambdaaws-api-gateway
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Reputation: 598

Malformed Lambda proxy response - Python

I know this is a duplicate of multiple questions, but for some reason I've not been able to figure out how to apply those solutions to my problem. The function works fine in Lambda tests, but fails when testing it via API Gateway.

import boto3
import json
import decimal
from boto3.dynamodb.conditions import Key, Attr

def lambda_handler(event, context):
    dynamodb = boto3.resource('dynamodb')

    table = dynamodb.Table('some_table')

    result = table.scan()

    response = {
        "status code": 200,
        "body": result["Items"]
    }

    return response

Here's the error log

Execution log for request 
Tue Dec 31 22:47:10 UTC 2019 : Starting execution for request: 
Tue Dec 31 22:47:10 UTC 2019 : HTTP Method: GET, Resource Path: /notes
Tue Dec 31 22:47:10 UTC 2019 : Method request path: {}
Tue Dec 31 22:47:10 UTC 2019 : Method request query string: {}
Tue Dec 31 22:47:10 UTC 2019 : Method request headers: {}
Tue Dec 31 22:47:10 UTC 2019 : Method request body before transformations: 
Tue Dec 31 22:47:10 UTC 2019 : Endpoint request URI: 
Tue Dec 31 22:47:10 UTC 2019 : Endpoint request headers: {x-amzn-lambda-integration-tag=1c231f4e-97e9-405a-aadf-ce37b34ccccd, Authorization=*****************************************************************************************************************************************************************************************************************************************************************************************************************************25519d, X-Amz-Date=20191231T224710Z, x-amzn-apigateway-api-id=4tjnqn8083, X-Amz-Source-Arn=arn:aws:execute-api:561581028295:4tjnqn8083/test-invoke-stage/GET/notes, Accept=application/json, User-Agent=AmazonAPIGateway_4tjnqn8083, X-Amz-Security-Token=IQoJb3JpZ2luX2VjEI7//////////wEaDmFwLXNvdXRoZWFzdC0yIkcwRQIgWl5Cw0aOXcxA4tBC8730wNLqnDVeo98T4+nu23F0CH8CIQCfqC5gJ6U4/UaXtHMOc1riROnwTj7AbYIKs/PCGam00irHAwj3//////////8BEAIaDDc5ODM3NjExMzg1MyIM3wb8dOuNeahpJ6o1KpsDbq4XLSkUYzoiplWuxXWlXvC3sTNceGepB4Gzgwzq8Aw4KO4tcI0GXDBjaNDCTDUpI3HMfxboA6r4v2H84VJ6YiSyIfpqRrv/2DiBortTr4iTARMBIVQb+Nc1v [TRUNCATED]
Tue Dec 31 22:47:10 UTC 2019 : Endpoint request body after transformations: {"resource":"/notes","path":"/notes","httpMethod":"GET","headers":null,"multiValueHeaders":null,"queryStringParameters":null,"multiValueQueryStringParameters":null,"pathParameters":null,"stageVariables":null,"requestContext":{"resourceId":"wb2eow","resourcePath":"/notes","httpMethod":"GET","extendedRequestId":"Fl1tQG5sywMF1tg=","requestTime":"31/Dec/2019:22:47:10 +0000","path":"/notes","accountId":"34523452346","protocol":"HTTP/1.1","stage":"test-invoke-stage","domainPrefix":"testPrefix","requestTimeEpoch":1577832430388,"requestId":"1c231f4e-97e9-405a-aadf-ce37b34ccccd","identity":{"cognitoIdentityPoolId":null,"cognitoIdentityId":null,"apiKey":"test-invoke-api-key","principalOrgId":null,"cognitoAuthenticationType":null,"userArn":"arn:aws:iam::561581028295:user/sanjay","apiKeyId":"test-invoke-api-key-id","userAgent":"aws-internal/3 aws-sdk-java/1.11.690 Linux/4.9.184-0.1.ac.235.83.329.metal1.x86_64 OpenJDK_64-Bit_Server_VM/25.232-b09 java/1.8.0_232 vendor/Oracle_Co [TRUNCATED]
Tue Dec 31 22:47:10 UTC 2019 : Sending request to https://lambda.amazonaws.com/2015-03-31/functions/arn:aws:lambda:2:562534523452345:function:listMyNote/invocations
Tue Dec 31 22:47:11 UTC 2019 : Received response. Status: 200, Integration latency: 1393 ms
Tue Dec 31 22:47:11 UTC 2019 : Endpoint response headers: {Date=Tue, 31 Dec 2019 22:47:11 GMT, Content-Type=application/json, Content-Length=118, Connection=keep-alive, x-amzn-RequestId=ac66aba1-d4c3-45ec-add3-f436cf177da9, x-amzn-Remapped-Content-Length=0, X-Amz-Executed-Version=$LATEST, X-Amzn-Trace-Id=root=1-5e0bcfee-7c8dc2fff64742d811635106;sampled=0}
Tue Dec 31 22:47:11 UTC 2019 : Endpoint response body before transformations: {"status code": 200, "body": "[{'id': '00f5fe2a-2c17-11ea-b5d9-dda84499b43e', 'text': 'Hello from the other side!'}]"}
Tue Dec 31 22:47:11 UTC 2019 : Execution failed due to configuration error: Malformed Lambda proxy response
Tue Dec 31 22:47:11 UTC 2019 : Method completed with status: 502

I've read multiple posts talking about the response body needing to be a string and to follow some kind of predefined format, but I'm not sure what I'm missing. Any help would be greatly appreciated.

Upvotes: 4

Views: 1815

Answers (1)

Arun Kamalanathan
Arun Kamalanathan

Reputation: 8603

It's statusCode. And you should return a string for body.

Here you go:

import json
response = {
  "statusCode": 200,
  "body": json.dumps(result["Items"])
}

Upvotes: 5

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