如何附加到 AWS S3 上的 json 文件

Question

I need to append to a json file on aws S3, python code is running on an EC2 instance.

In a local setting I can easily do this as follows:

import json

#example data
json_data = {"id": "123", "name": "XYZ", "transaction": [20.0, 30.0]}
# path
local_path = '/home/ubuntu/test.json'

with open(local_path, 'a', encoding='utf-8-sig') as file:
    json.dump(json_data, file)
    file.write('\n')
    file.close()

On EC2 I can connect to S3 as follows:

import boto
s3_open = boto.connect_s3(host='s3.eu-central-1.amazonaws.com')

I define the path to S3:

s3_path = 's3://my-bucket/test.json'

How can I append to this file using the logic described above?

Answer 1

S3 does not have an append action what you can do is download the file, append it yourself then upload it as a new version of the same object.

Something along these lines.

import json
import boto3

s3_path = '/some/s3/path'
bucket = 'somebucket'
local_data = {"id": "123", "name": "XYZ", "transaction": [20.0, 30.0]}

s3 = boto3.client('s3')
resp=s3.get_object(Bucket=bucket, Key=s3_path)
data=resp.get('Body')

json_data = json.loads(data)
json_data.append(local_data)
s3.put_object(Bucket=bucket, Key=s3_path, Body=json.dumps(json_data).encode())