Loop through compressed gzip files throws "ERROR [Errno 2] No such file or directory: 'part-r-00001.gz'" at second iteration - Python

Question

I am looping through multiple files within an s3 bucket. The first iteration works perfectly fine, but once jumping to the next I receive an "ERROR [Errno 2] No such file or directory: 'part-r-00001.gz'". (part-r-00000.gz was accessed correctly)

I am not sure why the file is not found as it is available in the bucket.

This is the code:

BUCKET = 'bucket'
PREFIX = 'path'

now = datetime.utcnow()
today = (now - timedelta(days=2)).strftime('%Y-%m-%d')
folder_of_the_day = PREFIX + today + '/'
logger.info("map folder: %s", folder_of_the_day)

client = boto3.client('s3')
response = client.list_objects_v2(Bucket=BUCKET, Prefix=folder_of_the_day)
for content in response.get('Contents', []):
    bucket_file = os.path.split(content["Key"])[-1]
    if bucket_file.endswith('.gz'):
        logger.info("----- starting with file: %s -----", bucket_file)
        try:
            with gzip.open(bucket_file, mode="rt") as file:
                for line in file:
                    //do something

        except Exception as e:
            logger.error(e)
            logger.critical("Failed to open file!")
            sys.exit(4)

Once executed for the second round, this is the output:

2022-06-18 12:14:48,027 [root] INFO ----- starting with file: part-r-00001.gz ----- 2022-06-18 12:14:48,028 [root] ERROR [Errno 2] No such file or directory: 'part-r-00001.gz'

Update Based on the comment I updated my code to a proper gzip method, but still the error remains. Once the first iteration is done, the second file is not being found.

This is the updated code:

try:
    with gzip.GzipFile(bucket_file) as gzipfile:
        decompressed_content = gzipfile.read()
        for line in decompressed_content.splitlines():
            //do something
            break

Answer 1

I think you can not use gzip.open on the S3 path directly.

You may need a proper gzip method to read files in S3 bucket.

Reading contents of a gzip file from a AWS S3 in Python