`plugins.GetAll()` was not locking the plugin map when checking if a
plugin exists, this can cause a race and potentially a panic if another
goroutine is trying to load a plugin into the map at the same time.
Also fixes a race during activation where a plugin inserts itself into
the plugin map but does not check if something else is already there.
This is already checked before trying to activate the plugin, however
the map lock is not held for this entire period, so other plugins may be
loaded during this time.
To fix, before inserting the plugin into the map, check if one with the
same name already exists and use that instead.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
pkg/ is a collection of utility packages used by the Docker project without being specific to its internals.
Utility packages are kept separate from the docker core codebase to keep it as small and concise as possible.
If some utilities grow larger and their APIs stabilize, they may be moved to their own repository under the
Docker organization, to facilitate re-use by other projects. However that is not the priority.
The directory pkg is named after the same directory in the camlistore project. Since Brad is a core
Go maintainer, we thought it made sense to copy his methods for organizing Go code :) Thanks Brad!
Because utility packages are small and neatly separated from the rest of the codebase, they are a good
place to start for aspiring maintainers and contributors. Get in touch if you want to help maintain them!
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