Ian Campbell 3af168c7df Ensure plugins can use PersistentPreRunE again. ...

I got a bit carried away in d4ced2ef77 ("allow plugins to have argument
which match a top-level flag.") and broke the ability of a plugin to use the
`PersistentPreRun(E)` hook on its top-level command (by unconditionally
overwriting it) and also broke the plugin framework if a plugin's subcommand
used those hooks (because they would shadow the root one). This could result in
either `dockerCli.Client()` returning `nil` or whatever initialisation the
plugin hoped to do not occuring.

This change revert the relevant bits and reinstates the requirement that a
plugin calls `plugin.PersistentPreRunE` if it uses that hook itself.

It is at least a bit nicer now since we avoid the need for the global struct
since the interesting state is now encapsulated in `tcmd` (and the closure).

In principal this could be done even more simply (by calling `tcmd.Initialize`
statically between `tcmd.HandleGlobalFlags` and `cmd.Execute`) however this has
the downside of _always_ initialising the cli (and therefore dialing the
daemon) even for the `docker-cli-plugin-metadata` command but also for the
`help foo` and `foo --help` commands (Cobra short-circuits the hooks in this
case).

Signed-off-by: Ian Campbell <ijc@docker.com>

2019-03-14 14:29:09 +00:00

..

main.go

Ensure plugins can use PersistentPreRunE again.

2019-03-14 14:29:09 +00:00