Copying multiple files from one folder to another in the same S3 bucket - json

Question

I am trying to copy files from one folder to another. However source folder has multiple folders in it and then multiple files. My requirement is to move all the files from each of these folder into single folder. I have about millions of file and each of these files have hardly 1 or 2 records.
Example -
source_folder - dev-bucket/data/
Inside this source_folder, I have following -
folder a - inside this folder, 10000 json files
folder b - inside this folder, 10000 json files
My aim - Target_folder - dev-bucket/final/20000 json files.
I tried writing below code, however, the processing time is also huge. Is there any other way to approach this?
try:
for obj in bucket.objects.filter(Prefix=source_folder):
old_source = {'Bucket': obj.bucket_name,'Key': obj.key}
file_count = file_count+1
new_obj = bucket.Object(final_file)
new_obj.copy(old_source)
except Exception as e:
logger.print("The process has failed to copy files from sftp location to base location", e)
exit(1)
I was thinking of merging the data into 1 single json file before moving the file. However, I am new to Python and AWS and am struggling to understand how should I read and write the data. I was trying to do below but am kind of stuck.
paginator = s3_client.get_paginator('list_objects_v2')
pages = paginator.paginate(Bucket=s3_bucket, Prefix=FOLDER)
response = []
for page in pages:
for obj in page['Contents']:
read_files = obj["Key"]
result = s3_client.get_object(Bucket=s3_bucket, Key=read_files)
text = result["Body"].read().decode()
response = response.append(text)
Can you please guide me? Many thanks in advance.

Answer 1

If you need copy one time, I sugget to use aws cli
aws s3 cp source destination --recursive
https://docs.aws.amazon.com/cli/latest/reference/s3/cp.html

Answer 2

If possible, it is best to avoid having high numbers of objects. They are slow to list and to iterate through.
From your question is seems that they contain JSON data and you are happy to merge the contents of files. A good way to do this is:
Use an AWS Glue crawler to inspect the contents of a directory and create a virtual 'table' in the AWS Glue Catalog
Then use Amazon Athena to SELECT data from that virtual table (which reads all the files) and copy it into a new table using CREATE TABLE AS
Depending upon how you intend to use the data in future, Athena can even convert it into a different format, such as Snappy-compressed Parquet files that are very fast for querying
If you instead just wish to continue with your code for copying files, you might consider activating Amazon S3 Inventory, which can provide a daily or weekly CSV file listing all objects. Your Python program could then use that inventory file as the input list of files, rather than having to call ListObjects.
However, I would highly recommend a strategy that reduces the number of objects you are storing unless there is a compelling reason to keep them all separate.
If you receive more files every day, you might even consider sending the data to an Amazon Kinesis Data Firehose, which can buffer data by size or time and store it in fewer files.