Tencent Cloud key pair cannot be removed if it is in a image, so
when user doesn't specify any log in method, such as ssh_password,
temporary key pair will be created and used, which eventually will
always fail.
This patch detach temporary key pair before creating image, so in
cleanup step, it can be deleted correctly.
Note that if user specifies a private key pair, we do not detach it,
because user might want to use it when creating new instances from this
image.
Spinnaker uses packer to create images, but tencentcloud builder
has name check to forbidden special characters such as dot(.) while
it is absolutely valid in API side.
This patch simply removes this limitation.
* 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
