s3cmd failed too many times

Question

I used to be a happy s3cmd user. However recently when I try to transfer a large zip file (~7Gig) to Amazon S3, I am getting this error:

$> s3cmd put thef         


        

Answer 1

This error occurs when Amazon returns an error: they seem to then disconnect the socket to keep you from uploading gigabytes of request to get back "no, that failed" in response. This is why for some people are getting it due to clock skew, some people are getting it due to policy errors, and others are running into size limitations requiring the use of the multi-part upload API. It isn't that everyone is wrong, or are even looking at different problems: these are all different symptoms of the same underlying behavior in s3cmd.

As most error conditions are going to be deterministic, s3cmd's behavior of throwing away the error message and retrying slower is kind of crazy unfortunate :(. Itthen To get the actual error message, you can go into /usr/share/s3cmd/S3/S3.py (remembering to delete the corresponding .pyc so the changes are used) and add a print e in the send_file function's except Exception, e: block.

In my case, I was trying to set the Content-Type of the uploaded file to "application/x-debian-package". Apparently, s3cmd's S3.object_put 1) does not honor a Content-Type passed via --add-header and yet 2) fails to overwrite the Content-Type added via --add-header as it stores headers in a dictionary with case-sensitive keys. The result is that it does a signature calculation using its value of "content-type" and then ends up (at least with many requests; this might be based on some kind of hash ordering somewhere) sending "Content-Type" to Amazon, leading to the signature error.

In my specific case today, it seems like -M would cause s3cmd to guess the right Content-Type, but it seems to do that based on filename alone... I would have hoped that it would use the mimemagic database based on the contents of the file. Honestly, though: s3cmd doesn't even manage to return a failed shell exit status when it fails to upload the file, so combined with all of these other issues it is probably better to just write your own one-off tool to do the one thing you need... it is almost certain that in the end it will save you time when you get bitten by some corner-case of this tool :(.