I have the following lambda function code for simply printing out the Author and metadata of an uploaded event of an S3 bucket:
from __future__ import print_function
import json
import urllib
import boto3
print('Loading function')
s3 = boto3.client('s3')
def lambda_handler(event, context):
#print("Received event: " + json.dumps(event, indent=2))
# bucket = event['Records'][0]['s3']['bucket']['name']
for record in event['Records']:
bucket = record[0]['s3']['bucket']['name']
key = record[0]['s3']['object']['key']
response = s3.head_object(Bucket=bucket, Key=key)
logger.info('Response: {}'.format(response))
print("Author : " + response['Metadata']['author'])
print("Description : " + response['Metadata']['description'])
However, I am getting the following error while testing:
{
"stackTrace": [
[
"/var/task/lambda_function.py",
17,
"lambda_handler",
"for record in event['Records']:"
]
],
"errorType": "KeyError",
"errorMessage": "'Records'"
}
Am I doing anything wrong while accessing the bucket name and key name of the S3 object? If not, then what am I doing wrong here?
bit late to the party. But here is my first post!
EXPLANATION:
When you test in lambda panel -> def lambda_handler(event, context) <- event is injected directly.
However in AWS API its neccessary to add Mapping Template or otherwise -> event <- is empty, thus resulting in quizzing:
this is null pointer. Records doesnt exist, since -> event <- doesnt exist.
SOLUTION:
You need to configure Integration Request inside AWS API. Click on Body Mapping Templates. Then add Mapping Template Set content type to application/json Then edit generated mapping template:
And edit Lambda function:
replace:
with:
don't know whether stack will ping you with this answer - so i call you @Dawny33 @KevinOelen @franklinsijo
As for explanation i figured it on my own. However "mapping template" comes from https://medium.com/simple-thoughts-amplified/passing-variables-from-aws-api-gateway-to-lambda-3c5d8602081b