S3 Object: Difference between 'expires' and 'expiration date'

Question

I am attempting to follow AWS documentation for aws s3 cp, which documents the --expires flag as:

--expires (string) The date and time at which the object is no longer cacheable.

...

Copying a local file to S3 with an expiration date

The following cp command copies a single file to a specified bucket and key that expires at the specified ISO 8601 timestamp:

aws s3 cp test.txt s3://mybucket/test2.txt --expires 2014-10-01T20:30:00Z

So, when I run a command just like the example above, I wind up with a file in S3 which has an "Overview" pane on the right side which looks like this:

The overview pane claims there is no "Expiration date". OK. But if I click through to the file, under Properties -> Metadata, I do see this:

So which one is right? Do the 'Expires' and 'Expiration date' timestamps mean different things somehow? Or are they the same thing, and the display is just buggy?

I have searched StackOverflow for several similar questions (here, here, and here ) but didn't find this question answered.

Answer 1

So, this is extremely poorly documented, but I think I found an answer here:

To add a Cache-Control or Expires header field to Amazon S3 objects using the Amazon S3 console ...

Choose Add Metadata, and then in the Key menu, choose Cache-Control or Expires. ...

For an Expires field, type a date and time in HTML format.

In other words, the Expires field that one sets via aws s3 cp ... --expires=... is intended to be an HTTP header which influences downstream caches (apparently CloudFront will honor this expires value). The S3 object is not deleted after this time.

Confusingly, this Expires value is completely different from the Expiration of an S3 object, which I gather can only be set by a Lifecycle Policy on the S3 bucket, not per-file at upload time (i.e. not using aws s3 cp ... ).