How could I use aws lambda to write file to s3 (python)?

Question

I have tried to use lambda function to write a file to S3, then test shows "succeeded" ,but nothing appeared in my S3 bucket. What happened? Does anyone can give me some advice or solutions? Thanks a lot. Here's my code.

import json
import boto3

def lambda_handler(event, context):

string = "dfghj"

file_name = "hello.txt"
lambda_path = "/tmp/" + file_name
s3_path = "/100001/20180223/" + file_name

with open(lambda_path, 'w+') as file:
    file.write(string)
    file.close()

s3 = boto3.resource('s3')
s3.meta.client.upload_file(lambda_path, 's3bucket', s3_path)

Answer 1

I've had success streaming data to S3, it has to be encoded to do this:

import boto3

def lambda_handler(event, context):
    string = "dfghj"
    encoded_string = string.encode("utf-8")

    bucket_name = "s3bucket"
    file_name = "hello.txt"
    lambda_path = "/tmp/" + file_name
    s3_path = "/100001/20180223/" + file_name

    s3 = boto3.resource("s3")
    s3.Bucket(bucket_name).put_object(Key=s3_path, Body=encoded_string)

If the data is in a file, you can read this file and send it up:

with open(filename) as f:
    string = f.read()

encoded_string = string.encode("utf-8")