Boto3 to download all files from a S3 Bucket
When working with buckets that have 1000+ objects its necessary to implement a solution that uses the NextContinuationToken
on sequential sets of, at most, 1000 keys. This solution first compiles a list of objects then iteratively creates the specified directories and downloads the existing objects.
import boto3
import os
s3_client = boto3.client('s3')
def download_dir(prefix, local, bucket, client=s3_client):
"""
params:
- prefix: pattern to match in s3
- local: local path to folder in which to place files
- bucket: s3 bucket with target contents
- client: initialized s3 client object
"""
keys = []
dirs = []
next_token = ''
base_kwargs = {
'Bucket':bucket,
'Prefix':prefix,
}
while next_token is not None:
kwargs = base_kwargs.copy()
if next_token != '':
kwargs.update({'ContinuationToken': next_token})
results = client.list_objects_v2(**kwargs)
contents = results.get('Contents')
for i in contents:
k = i.get('Key')
if k[-1] != '/':
keys.append(k)
else:
dirs.append(k)
next_token = results.get('NextContinuationToken')
for d in dirs:
dest_pathname = os.path.join(local, d)
if not os.path.exists(os.path.dirname(dest_pathname)):
os.makedirs(os.path.dirname(dest_pathname))
for k in keys:
dest_pathname = os.path.join(local, k)
if not os.path.exists(os.path.dirname(dest_pathname)):
os.makedirs(os.path.dirname(dest_pathname))
client.download_file(bucket, k, dest_pathname)
I have the same needs and created the following function that download recursively the files.
The directories are created locally only if they contain files.
import boto3
import os
def download_dir(client, resource, dist, local='/tmp', bucket='your_bucket'):
paginator = client.get_paginator('list_objects')
for result in paginator.paginate(Bucket=bucket, Delimiter='/', Prefix=dist):
if result.get('CommonPrefixes') is not None:
for subdir in result.get('CommonPrefixes'):
download_dir(client, resource, subdir.get('Prefix'), local, bucket)
for file in result.get('Contents', []):
dest_pathname = os.path.join(local, file.get('Key'))
if not os.path.exists(os.path.dirname(dest_pathname)):
os.makedirs(os.path.dirname(dest_pathname))
if not file.get('Key').endswith('/'):
resource.meta.client.download_file(bucket, file.get('Key'), dest_pathname)
The function is called that way:
def _start():
client = boto3.client('s3')
resource = boto3.resource('s3')
download_dir(client, resource, 'clientconf/', '/tmp', bucket='my-bucket')
import os
import boto3
#initiate s3 resource
s3 = boto3.resource('s3')
# select bucket
my_bucket = s3.Bucket('my_bucket_name')
# download file into current directory
for s3_object in my_bucket.objects.all():
# Need to split s3_object.key into path and file name, else it will give error file not found.
path, filename = os.path.split(s3_object.key)
my_bucket.download_file(s3_object.key, filename)