How to update metadata of an existing object in AWS S3 using python boto3?

Question

boto3 documentation does not clearly specify how to update the user metadata of an already existing S3 Object.

Answer 1

It can be done using the copy_from() method -

import boto3

s3 = boto3.resource('s3')
s3_object = s3.Object('bucket-name', 'key')
s3_object.metadata.update({'id':'value'})
s3_object.copy_from(CopySource={'Bucket':'bucket-name', 'Key':'key'}, Metadata=s3_object.metadata, MetadataDirective='REPLACE')