从 S3 下载文件时 AWS Lambda 中出现“只读文件系统”错误

当我将 file.csv 放入 S3 存储桶时，我在 lambda 函数中看到以下错误。该文件并不大，我什至在打开文件进行读取之前添加了 60 秒的睡眠时间，但由于某种原因，该文件附加了额外的“.6CEdFe7C”。这是为什么？

[Errno 30] Read-only file system: u'/file.csv.6CEdFe7C': IOError
Traceback (most recent call last):
File "/var/task/lambda_function.py", line 75, in lambda_handler
s3.download_file(bucket, key, filepath)
File "/var/runtime/boto3/s3/inject.py", line 104, in download_file
extra_args=ExtraArgs, callback=Callback)
File "/var/runtime/boto3/s3/transfer.py", line 670, in download_file
extra_args, callback)
File "/var/runtime/boto3/s3/transfer.py", line 685, in _download_file
self._get_object(bucket, key, filename, extra_args, callback)
File "/var/runtime/boto3/s3/transfer.py", line 709, in _get_object
extra_args, callback)
File "/var/runtime/boto3/s3/transfer.py", line 723, in _do_get_object
with self._osutil.open(filename, 'wb') as f:
File "/var/runtime/boto3/s3/transfer.py", line 332, in open
return open(filename, mode)
IOError: [Errno 30] Read-only file system: u'/file.csv.6CEdFe7C'

Code:

def lambda_handler(event, context):

    s3_response = {}
    counter = 0
    event_records = event.get("Records", [])

    s3_items = []
    for event_record in event_records:
        if "s3" in event_record:
            bucket = event_record["s3"]["bucket"]["name"]
            key = event_record["s3"]["object"]["key"]
            filepath = '/' + key
            print(bucket)
            print(key)
            print(filepath)
            s3.download_file(bucket, key, filepath)

上面的结果是：

mytestbucket
file.csv
/file.csv
[Errno 30] Read-only file system: u'/file.csv.6CEdFe7C'

如果密钥/文件是“file.csv”，那么为什么 s3.download_file 方法会尝试下载“file.csv.6CEdFe7C”？我猜测当函数被触发时，文件是 file.csv.xxxxx 但当它到达第 75 行时，文件被重命名为 file.csv？

Only /tmp似乎在 AWS Lambda 中是可写的。

因此这会起作用：

filepath = '/tmp/' + key

参考：

• https://aws.amazon.com/blogs/compute/choosing- Between-aws-lambda-data-storage-options-in-web-apps https://aws.amazon.com/blogs/compute/choosing-between-aws-lambda-data-storage-options-in-web-apps
• https://docs.aws.amazon.com/lambda/latest/dg/gettingstarted-limits.html https://docs.aws.amazon.com/lambda/latest/dg/gettingstarted-limits.html