Without conflicting over the name of the launch template that they create/delete.
Previously, the launch template name was just hard coded to `packer-fleet-launch-template`, but since AWS enforces unique template names within an account, this caused simultaneously running packer instances to hit template-already-exists errors when creating their templates and race-conditions around deleting the template. Now, the template name is randomly generated on each run, so there should be no conflicts.
* I had to contextualise Communicator.Start and RemoteCmd.StartWithUi
NOTE: Communicator.Start starts a RemoteCmd but RemoteCmd.StartWithUi will run the cmd and wait for a return, so I renamed StartWithUi to RunWithUi so that the intent is clearer.
Ideally in the future RunWithUi will be named back to StartWithUi and the exit status or wait funcs of the command will allow to wait for a return. If you do so please read carrefully https://golang.org/pkg/os/exec/#Cmd.Stdout to avoid a deadlock
* cmd.ExitStatus to cmd.ExitStatus() is now blocking to avoid race conditions
* also had to simplify StartWithUi
to accept a list of strings (for Amazon builders).
Per this change, `temporary_security_group_source_cidr` in the configuration:
1. Will be renamed to `temporary_security_group_source_cidrs`.
2. Will accept a list of CIDRs.
3. Will have its documentation updated to reflect this change.
4. Will have a fixer attached for newer templates to avail of.
* 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
Previously, when you built from an existing image, you were unable
to reconfigure block device mappings, as it just took them and
copied them over. This allows users to specify new, custom
block device mappings, even when building from an existing
image.