[Python] Get files from S3 with lambda

I'm trying to retrieve files from an AWS S3 bucket using a Lambda function, but my script keeps timing out, and I can't figure out why. "errorMessage": "2025-05-16T14:37:13.093Z fdb6***4165 Task timed out after 30.03 seconds"

The code I'm using is a basic script I got from the Doc:

import boto3

def lambda_handler(event, context):
bucket_name = "<myS3_bucket"
file_key = "<path_to/file.csv>"

s3 = boto3.resource('s3')
for bucket in s3.buckets.all():
print(bucket.name)


I create my Lambda with terraform, here is my Lambda policy:

resource "aws_iam_role" "lambda_role" {
name = "${var.lambda_name}_role"
assume_role_policy = jsonencode({
Statement = [
{
Action = "sts:AssumeRole"
Effect = "Allow"
Principal = {
Service = "lambda.amazonaws.com"
}
}]
})
}

resource "aws_iam_role_policy_attachment" "S3_read_only" {
role = aws_iam_role.lambda_role.name
policy_arn = "arn:aws:iam::awsolicy/AmazonS3FullAccess"
}
resource "aws_iam_role_policy_attachment" "lambda_logs" {
role = aws_iam_role.lambda_role.name
policy_arn = "arn:aws:iam::awsolicy/service-role/AWSLambdaBasicExecutionRole"
}
resource "aws_iam_role_policy_attachment" "lambda_vpc_access" {
role = aws_iam_role.lambda_role.name
policy_arn = "arn:aws:iam::awsolicy/service-role/AWSLambdaVPCAccessExecutionRole"
}


Security group:

data "aws_vpc" "default" {
default = true
}
resource "aws_security_group" "lambda_sg" {
name = "sg_${var.lambda_name}"
description = "Allow all the ports needed for lambda"
vpc_id = data.aws_vpc.default.id

# allow all inbound traffic
ingress {
from_port = 0
to_port = 0
protocol = "-1"
cidr_blocks = ["0.0.0.0/0"]
}

# allow all outbound traffic
egress {
from_port = 0
to_port = 0
protocol = "-1"
cidr_blocks = ["0.0.0.0/0"]
}
}
}


I also add bucket policy:

resource "aws_s3_bucket_policy" "lambda_s3_access_policy" {
bucket = "superset-dockerfiles"
policy = jsonencode({
Version = "2012-10-17",
Statement = [
{
Effect = "Allow",
Principal = {
AWS = aws_iam_role.lambda_role.arn
},
Action = [
"s3:GetObject",
"s3:ListBucket"
],
Resource = [
"arn:aws:s3:::superset-dockerfiles",
"arn:aws:s3:::superset-dockerfiles/*"
]
}
]
})
}


What am i missing ?

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