As part of making graphdrivers support pluginv2, a PluginGetter
interface was necessary for cleaner separation and avoiding import
cycles.
This commit creates a PluginGetter interface and makes pluginStore
implement it. Then the pluginStore object is created in the daemon
(rather than by the plugin manager) and passed to plugin init as
well as to the different subsystems (eg. graphdrivers, volumedrivers).
A side effect of this change was that some code was moved out of
experimental. This is good, since plugin support will be stable soon.
Signed-off-by: Anusha Ragunathan <anusha@docker.com>
Split plugin package into `store` and `v2/plugin`. Now the functionality
is clearly delineated:
- Manager: Manages the global state of the plugin sub-system.
- PluginStore: Manages a collection of plugins (in memory and on-disk)
- Plugin: Manages the single plugin unit.
This also facilitates splitting the global PluginManager lock into:
- PluginManager lock to protect global states.
- PluginStore lock to protect store states.
- Plugin lock to protect individual plugin states.
Importing "github.com/docker/docker/plugin/store" will provide access
to plugins and has lesser dependencies when compared to importing the
original monolithic `plugin package`.
Signed-off-by: Anusha Ragunathan <anusha@docker.com>
