Listing installed plugins is a sequential operation that iterates on
each potential plugin binary under PACKER_PLUGIN_PATH.
Each potential candidate may be executed in order to get its
description, and to match that what is reported by the plugin binary
matches what is effectively installed on the filesystem.
This operation may be causing lots of I/O syncs, and if done
sequentially on a rather large number of installed plugins will take
time.
In order to make this faster, we paralellise listing installations, so
we run those commands in parallel in order to minimise idle waiting time
on the main process.
Since we'll only look in the plugin directory, and not from multiple
sources now, for installing/listing plugins, we can simplify the
structures which used to accept multiple directories so they only accept
one.
Since we're removing the alternative plugin installation directories in
favour of only supporting installing them in the PACKER_PLUGIN_PATH
directory, we only return one directory when getting the known plugin
directories.
The enumeration for FlagSetFlags, which presumably was added when the
Meta structure was introduced, aims to pre-populate the flagset for a
subcommand with a series of arguments.
However, despite it being documented, it is actually not used, and
therefore can safely be removed from the codebase.
* Updating the license from MPL to Business Source License
Going forward, this project will be licensed under the Business Source License v1.1. Please see our blog post for more details at https://hashi.co/bsl-blog, FAQ at https://hashi.co/license-faq, and details of the license at www.hashicorp.com/bsl.
* Update copyright file headers to BUSL-1.1
---------
Co-authored-by: hashicorp-copywrite[bot] <110428419+hashicorp-copywrite[bot]@users.noreply.github.com>
Lucas Bajolet
hashicorp-copywrite[bot]
