immutant/overlay — pull request #3 by jballanc (2013-01-23 18:26:27+00:00)
Title: Improve error handling and reporting for installs

This is a sizeable refactor of the way that the Overlay project handles
downloading and installing artifacts. Highlights include:

* Adds a protocol for BinaryArtifacts and adds two implementations for
Incremental and Release builds. The protocol includes functions to
retrieve the remote URL and the download file size.

* Utilizes a HEAD request to determine file size when a metadata file is
not available.

* Checks for 404s before attempting a download. Fails more gracefully
when something goes wrong during download.

In order to support all these changes, one additional dependency was added:
clj-http-lite.