* removed packer.Cache and references since packer.Cache is never used except in the download step. The download step now uses the new func packer.CachePath(targetPath) for this, the behavior is the same.
* removed download code from packer that was reimplemented into the go-getter library: progress bar, http download restart, checksuming from file, skip already downloaded files, symlinking, make a download cancellable by context.
* on windows if packer is running without symlinking rights and we are getting a local file, the file will be copied instead to avoid errors.
* added unit tests for step_download that are now CI tested on windows, mac & linux.
* files are now downloaded under cache dir `sha1(filename + "?checksum=" + checksum) + file_extension`
* since the output dir is based on the source url and the checksum, when the checksum fails, the file is auto deleted.
* a download file is protected and locked by a file lock,
* updated docs
* updated go modules and vendors
* simplified the downloader interface, and removed the total/current values from them
* downloaders use a proxy reader that will add all read bytes to progress
* removed unused const mtu
* DownloadClient doesn't need a downloader, so I removed it too
The previous version used fmt.Fscanln which sounds like it should scan
for a whole line, but it actually errors if there is more than a single
word/token given. You can see this here https://play.golang.org/p/1RYXdtPSbk
And looking at the only usage of this function in core it won't break
anything to change it to actually return whole lines instead.
line, err := ui.Ask("[c] Clean up and exit, [a] abort without cleanup, or [r] retry step (build may fail even if retry succeeds)?")
Closes#4474
Adrien Delorme
Megan Marsh
Adrien Delorme
xinau
Ashley Lowde
Matthew Hooker
Ash Berlin
Mitchell Hashimoto