Download file from AWS S3 using Python

Question

I am trying to download a file from Amazon S3 bucket to my local using the below code but I get an error saying "Unable to locate credentials"

Given below is the code I have written:

from boto3.session import Session import boto3  ACCESS_KEY = 'ABC' SECRET_KEY = 'XYZ'  session = Session(aws_access_key_id=ACCESS_KEY,               aws_secret_access_key=SECRET_KEY) s3 = session.resource('s3') your_bucket = s3.Bucket('bucket_name')  for s3_file in your_bucket.objects.all():     print(s3_file.key) # prints the contents of bucket  s3 = boto3.client ('s3')  s3.download_file('your_bucket','k.png','/Users/username/Desktop/k.png') 

Could anyone help me on this. Thanks.

Answer 1

You are not using the session you created to download the file, you're using s3 client you created. If you want to use the client you need to specify credentials.

your_bucket.download_file('k.png', '/Users/username/Desktop/k.png') 

or

s3 = boto3.client('s3', aws_access_key_id=... , aws_secret_access_key=...) s3.download_file('your_bucket','k.png','/Users/username/Desktop/k.png') 

Answer 2

From an example in the official documentation, the correct format is:

import boto3  s3 = boto3.client('s3', aws_access_key_id=... , aws_secret_access_key=...) s3.download_file('BUCKET_NAME', 'OBJECT_NAME', 'FILE_NAME') 

You can also use a file-like object opened in binary mode.

s3 = boto3.client('s3', aws_access_key_id=... , aws_secret_access_key=...) with open('FILE_NAME', 'wb') as f:     s3.download_fileobj('BUCKET_NAME', 'OBJECT_NAME', f)     f.seek(0) 

---

The code in question uses s3 = boto3.client ('s3'), which does not provide any credentials.

The format for authenticating a client is shown here:

import boto3 client = boto3.client(     's3',     aws_access_key_id=ACCESS_KEY,     aws_secret_access_key=SECRET_KEY,     aws_session_token=SESSION_TOKEN, )  # Or via the Session session = boto3.Session(     aws_access_key_id=ACCESS_KEY,     aws_secret_access_key=SECRET_KEY,     aws_session_token=SESSION_TOKEN, ) 

---

And lastly you can also re-use the authenticated session you created to get the bucket, and then download then file from the bucket.

from boto3.session import Session import boto3  ACCESS_KEY = 'ABC' SECRET_KEY = 'XYZ'  session = Session(aws_access_key_id=ACCESS_KEY,               aws_secret_access_key=SECRET_KEY)  # session is authenticated and can access the resource in question  session.resource('s3')     .Bucket('bucket_name')     .download_file('k.png','/Users/username/Desktop/k.png')