CODEWITHSUNDEEP
python-2.7amazon-web-servicesamazon-s3boto
ylun
ylun

Reputation: 2534

boto - What exactly is a key?

AS the title says, what is a key in boto?

I was not able to find this information on their official documentation or on any other third party website. Could anybody provide this info?

Here are some examples of the usage of the key object:

def download_file(key_name, storage):
    key = bucket.get_key(key_name)
    try:
        storage.append(key.get_contents_as_string())
    except:
        print "Some error message."

and:

for key in keys_to_process:
    pool.spawn_n(download_file, key.key, file_contents)
pool.waitall()

Upvotes: 1

Views: 3133

Answers (2)

cgseller
cgseller

Reputation: 4043

In your code example - key is the object reference to the unique identifier within a bucket.

Think of buckets as a table in a database think of keys as the rows in the table you reference the key (better known as an object) in the bucket.

often in boto (not boto3) works like this

from boto.s3.connection import S3Connection
connection = S3Connection()  # assumes you have a .boto or boto.cfg setup
bucket = connection.get_bucket('my_bucket_name_here') # this is like the table name in SQL, select OBJECT form TABLENAME
key = bucket.get_key('my_key_name_here') this is the OBJECT in the above SQL example.  key names are a string, and there is a convention that says if you put a '/' in the name, a viewer/tool should treat it like a path/folder for the user, e.g.  my/object_name/is_this is really just a key inside the bucket, but most viewers will show a my folder, and an object_name folder, and then what looks like a file called is_this simply by UI convention

Upvotes: 3

Michael - sqlbot
Michael - sqlbot

Reputation: 179114

Since you appear to be talking about Simple Storage Service (S3), you'll find that information on Page 1 of the S3 documentation.

Each object is stored and retrieved using a unique developer-assigned key.

A key is the unique identifier for an object within a bucket. Every object in a bucket has exactly one key. Because the combination of a bucket, key, and version ID uniquely identify each object, Amazon S3 can be thought of as a basic data map between "bucket + key + version" and the object itself. Every object in Amazon S3 can be uniquely addressed through the combination of the web service endpoint, bucket name, key, and optionally, a version. For example, in the URL http://doc.s3.amazonaws.com/2006-03-01/AmazonS3.wsdl, "doc" is the name of the bucket and "2006-03-01/AmazonS3.wsdl" is the key.

http://docs.aws.amazon.com/AmazonS3/latest/dev/Introduction.html

The key is just a string -- the "path and filename" of the object in the bucket, without a leading /.

Upvotes: 2

Related Questions