Re: [Duplicity-talk] S3 ECONNRESET during restore results in SHA1 hash mismatch

[Aphyr]

On 05/04/2016 04:07 PM, address@hidden wrote:
> probably should, but nobody contributed that so far ;).. ede/duply.net

To follow up: I was never able to figure out why the backend returns 
successfully after ECONNRESET (alas, my understanding of python error handling 
is still tentative), but I *was* able to complete my restore by patching 
restore_get_enc_fileobj to retry downloads when signature verification failed. 
Here's my (probably terrible) solution, in case anyone else runs into a similar 
problem.

def restore_get_enc_fileobj(backend, filename, volume_info):
    """
    Return plaintext fileobj from encrypted filename on backend

    If volume_info is set, the hash of the file will be checked,
    assuming some hash is available.  Also, if globals.sign_key is
    set, a fatal error will be raised if file not signed by sign_key.

    """
    parseresults = file_naming.parse(filename)
    for n in range(100):
        tdp = dup_temp.new_tempduppath(parseresults)
        backend.get(filename, tdp)

        """ verify hash of the remote file """
        verified, hash_pair, calculated_hash = restore_check_hash(volume_info, 
tdp)
        if verified:
            break

        """ verification failed """
        log.Warn("%s\n %s\n %s\n %s\n" %
                        (_("Invalid data - %s hash mismatch for file:") % 
hash_pair[0],
                         util.ufn(filename),
                         _("Calculated hash: %s") % calculated_hash,
                         _("Manifest hash: %s") % hash_pair[1]),
                        log.ErrorCode.mismatched_hash)
        """ abandon file and retry """
        tdp.delete()
        time.sleep(10)

    fileobj = tdp.filtered_open_with_delete("rb")
    if parseresults.encrypted and globals.gpg_profile.sign_key:
        restore_add_sig_check(fileobj)
    return fileobj

--Kyle