使用AWS Lambda将存储在S3 Bucket中的JSON文件转换为CSV

Question

我是Lambda和Python的新手，我遇到了Lambda函数的问题。我有几个JSON文件存储在S3桶中，我希望将所有JSON文件转换为CSV格式。因为我指的是本教程中发布的Lambda函数:https://sysadmins.co.za/convert-csv-to-json-files-with-aws-lambda-and-s3-events/

Lambda函数:

import json
import csv
import boto3
import os
import datetime as dt
s3 = boto3.client('s3')
def lambda_handler(event, context):

datestamp = dt.datetime.now().strftime("%Y/%m/%d")
timestamp = dt.datetime.now().strftime("%s")

filename_json = "/tmp/file_{ts}.json".format(ts=timestamp)
filename_csv = "/tmp/file_{ts}.csv".format(ts=timestamp)
keyname_s3 = "uploads/output/{ds}/{ts}.json".format(ds=datestamp, ts=timestamp)

json_data = []
for record in event['Records']:
bucket_name = record['s3']['bucket']['name']
key_name = record['s3']['object']['key']

s3_object = s3.get_object(Bucket=bucket_name, Key=key_name)
data = s3_object['Body'].read()
contents = data.decode('utf-8')

with open(filename_csv, 'a') as csv_data:
csv_data.write(contents)

with open(filename_csv) as csv_data:
csv_reader = csv.DictReader(csv_data)
for csv_row in csv_reader:
json_data.append(csv_row)

with open(filename_json, 'w') as json_file:
json_file.write(json.dumps(json_data))

with open(filename_json, 'r') as json_file_contents:
response = s3.put_object(Bucket=bucket_name, Key=keyname_s3, Body=json_file_contents.read())
os.remove(filename_csv)
os.remove(filename_json)
return {
'statusCode': 200,
'body': json.dumps('CSV converted to JSON and available at: {bucket}/{key}'.format(bucket=bucket_name,key=keyname_s3))
}

我想使用Lambda实现类似的结果，但从JSON到CSV。我该怎么做呢?

Answer 1

我建议你看看convtools库:

from convtools import conversion as c
from convtools.contrib.tables import Table
import json
# input.json
"""
{
"records": [
{"a": 1, "b": "c"},
{"a": 2, "b": "d"},
{"a": 3, "b": "e"}
]
}
"""
with open("input.json") as f:
input_data = json.load(f)

Table.from_rows(input_data["records"]).into_csv("output.csv")
# output.csv
"""
a,b
1,c
2,d
3,e
"""