Baldowl

my nest somewhere in GitHub's forest

Multipart Uploads With Fog

A couple of days ago I spent the lunch playing, again, with fog; this time I was interested in S3’s multipart upload feature, so fired up fog’s cli and started typing away to test it.

Fog still does not have any model for this recently added feature, so I had to resort to use the lower level mechanism of requests. Here’s a (bad, procedural, defective of any error checking) script I wrote afterward by collecting and cleaning up the cli session:

So, roughly speaking, I started asking AWS the list of pending multipart uploads (and so discovered a couple of them initiated by another tool and dating back from an earlier upload gone south twice), set up a new one and uploaded the previously split parts, ending that section showing the parts’ identifiers assigned by AWS, just to be sure they were really there, and, again, the list of pending multipart uploads to confirm that somehow I did something right; then I asked AWS to reassemble the file, check that there were no more pending uploads and get the new file metadata.

Some notes:

  • I think it’s better to pass File objects to fog instead of reading files into memory and passing their contents to fog (a File object will be read and transfered in chunks by excon);
  • I prefer to wrap file operation (even the upload of single files) in a block passed to File::open, so that the file is automatically closed when done.

Inspired by the experience (or disgusted by the amount of low level operations?), I jotted down what I’d like to see as higher level interface… perhaps I should try to find some time to fork fog :-)

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