IOError in Boto3 download_file

Question

Background

I am using the following Boto3 code to download file from S3.

for record in event['Records']:
    bucket = record['s3']['bucket']['name']
    key = record['s3']['object']['key']
    print (key)
    if key.find('/') < 0 :
    if len(key) > 4 and key[-5:].lower() == '.json': //File is uploaded outside any folder

        download_path = '/tmp/{}{}'.format(uuid.uuid4(), key)
    else:
        download_path = '/tmp/{}/{}'.format(uuid.uuid4(), key)//File is uploaded inside a folder

If a new file is uploaded in S3 bucket, this code is triggered and that newly uploaded file is downloaded by this code.

This code works fine when uploaded outside any folder.

However, when I upload a file inside a directory, IO error happens. Here is a dump of the IO error I am encountering.

[Errno 2] No such file or directory: /tmp/316bbe85-fa21-463b-b965-9c12b0327f5d/test1/customer1.json.586ea9b8: IOError

test1 is the directory inside my S3 bucket where customer1.json is uploaded.

Query

Any thoughts on how to resolve this error?

Answer 1

Error raised because you attempted to download and save file into directory which not exists. Use os.mkdir prior downloading file to create an directory.

# ...
else:
    item_uuid = str(uuid.uuid4())
    os.mkdir('/tmp/{}'.format(item_uuid))
    download_path = '/tmp/{}/{}'.format(item_uuid, key)  # File is uploaded inside a folder

Note: It's better to use os.path.join() while operating with systems paths. So code above could be rewritten to:

# ...
else:
    item_uuid = str(uuid.uuid4())
    os.mkdir(os.path.join(['tmp', item_uuid]))
    download_path = os.path.join(['tmp', item_uuid, key]))

Also error may be raises because you including '/tmp/' in download path for s3 bucket file, do not include tmp folder as likely it's not exists on s3. Ensure you are on the right way by using that articles:

• Amazon S3 upload and download using Python/Django

• Python s3 examples

Answer 2

I faced the same issue, and the error message caused a lot of confusion, (the random string extension after the file name). In my case it was caused by the missing directory path, which didn't exist.