This assumes you are familar with the basic configurations needed to connect to Amazon Web Services (AWS) using Python boto3. If not, check out my article Python (Scripting) - Getting Started with Amazon Web Services (AWS) boto3.

Here is the minimal boilerplate code without any error handling to list your S3 Buckets

#!/usr/bin/python3
import boto3
import os

client = boto3.client('s3')
s3_buckets = client.list_buckets()
print(f"s3_buckets = {s3_buckets}")

Or, os.environ['AWS_PROFILE'] can be used to specify the profile in /home/john.doe/.aws/config and /home/john.doe/.aws/credentials to use.

import boto3
import os

os.environ['AWS_PROFILE'] = 'johndoe'

client = boto3.client('s3')
s3_buckets = client.list_buckets()
print(f"s3_buckets = {s3_buckets}")

Which should return something  that contains something like this.

'Buckets': [
    {'Name': 'my-bucket-foo', 
     'CreationDate': datetime.datetime(2023, 7, 21, 23, 17, 2, tzinfo=tzutc())
    }, 
    {'Name': 'my-bucket-bar', 
     'CreationDate': datetime.datetime(2023, 8, 21, 11, 9, 20, tzinfo=tzutc())
    }
  ], 
}

And here is how you can list the objects in a bucket.

client = boto3.client('s3')
s3_buckets = client.list_buckets()

for s3_bucket in s3_buckets['Buckets']:
  print(f"s3_bucket name = {s3_bucket['Name']}")

  if s3_bucket['Name'] == 'my-bucket-bar':
    objects = client.list_objects(Bucket='my-bucket-bar')
    for object in objects['Contents']:
      print(f"object = {object['Key']}")

Something like this should returned.

s3_bucket name = my-bucket-foo
s3_bucket name = my-bucket-bar
object = hello.html
object = index.html
object = main.js

Or, get_object can be used to determine if a specific object exists in an S3 Bucket.

#!/usr/bin/python3
import boto3
from botocore.exceptions import ClientError
import os

client = boto3.client('s3')
s3_buckets = client.list_buckets()

objects = ['foo.txt', 'bar.txt']

for s3_bucket in s3_buckets['Buckets']:
  print(f"s3_bucket name = {s3_bucket['Name']}")

  if s3_bucket['Name'] == 'my-bucket-abc123':
    for object in objects:
      try:
        response = client.get_object(Bucket='my-bucket-abc123', Key=object)
      except Exception as exception:
        if exception.response['Error']['Code'] == "NoSuchKey":
          print(f"object {object} does NOT exist in S3 Bucket my-bucket-abc123")
      else:
          print(f"object {object} exists in S3 Bucket my-bucket-abc123")

Something like this should returned.

foo.txt does NOT exist in my-bucket-abc123
bar.txt does exists in my-bucket-abc123