How to filter for objects in a given S3 directory using boto3

Using boto3, you can filter for objects in a given bucket by directory by applying a prefix filter.

Instead of iterating all objects using

for obj in my_bucket.objects.all():
    pass # ...

(see How to use boto3 to iterate ALL objects in a Wasabi / S3 bucket in Python for a full example)

you can apply a prefix filter using

for obj in my_bucket.objects.filter(Prefix="MyDirectory/"):
    print(obj)

Don’t forget the trailing / for the prefix argument ! Just using filter(Prefix="MyDirectory") without a trailing slash will also match e.g. MyDirectoryFileList.txt.

This complete example prints the object description for every object in the 10k-Test-Objects directory (from our post on How to use boto3 to create a lot of test files in Wasabi / S3 in Python).

import boto3

# Create connection to Wasabi / S3
s3 = boto3.resource('s3',
    endpoint_url = 'https://s3.eu-central-1.wasabisys.com',
    aws_access_key_id = 'MY_ACCESS_KEY',
    aws_secret_access_key = 'MY_SECRET_KEY'
)

# Get bucket object
my_bucket = s3.Bucket('boto-test')

# Iterate over objects in bucket
for obj in my_bucket.objects.filter(Prefix="MyDirectory"):
    print(obj)

Don’t forget to fill in MY_ACCESS_KEY and MY_SECRET_KEY. Depending on what region and what S3-compatible service you use, you might need to use another endpoint URL instead of https://s3.eu-central-1.wasabisys.com.

Example output:

s3.ObjectSummary(bucket_name='boto-test', key='10k-Test-Objects/1.txt')
s3.ObjectSummary(bucket_name='boto-test', key='10k-Test-Objects/10.txt')
s3.ObjectSummary(bucket_name='boto-test', key='10k-Test-Objects/100.txt')
s3.ObjectSummary(bucket_name='boto-test', key='10k-Test-Objects/1000.txt')
s3.ObjectSummary(bucket_name='boto-test', key='10k-Test-Objects/10000.txt')
s3.ObjectSummary(bucket_name='boto-test', key='10k-Test-Objects/1001.txt')
s3.ObjectSummary(bucket_name='boto-test', key='10k-Test-Objects/1002.txt')
s3.ObjectSummary(bucket_name='boto-test', key='10k-Test-Objects/1003.txt')
s3.ObjectSummary(bucket_name='boto-test', key='10k-Test-Objects/1004.txt')
s3.ObjectSummary(bucket_name='boto-test', key='10k-Test-Objects/1005.txt')
s3.ObjectSummary(bucket_name='boto-test', key='10k-Test-Objects/1006.txt')
s3.ObjectSummary(bucket_name='boto-test', key='10k-Test-Objects/1007.txt')
s3.ObjectSummary(bucket_name='boto-test', key='10k-Test-Objects/1008.txt')
s3.ObjectSummary(bucket_name='boto-test', key='10k-Test-Objects/1009.txt')
s3.ObjectSummary(bucket_name='boto-test', key='10k-Test-Objects/101.txt')
[...]