Lint on pkg/* packages

- pkg/useragent
- pkg/units
- pkg/ulimit
- pkg/truncindex
- pkg/timeoutconn
- pkg/term
- pkg/tarsum
- pkg/tailfile
- pkg/systemd
- pkg/stringutils
- pkg/stringid
- pkg/streamformatter
- pkg/sockets
- pkg/signal
- pkg/proxy
- pkg/progressreader
- pkg/pools
- pkg/plugins
- pkg/pidfile
- pkg/parsers
- pkg/parsers/filters
- pkg/parsers/kernel
- pkg/parsers/operatingsystem

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

plugins/discovery.go

@@ -12,22 +12,28 @@ import (
 )
 
 var (
+	// ErrNotFound plugin not found
 	ErrNotFound = errors.New("Plugin not found")
 	socketsPath = "/run/docker/plugins"
 	specsPaths  = []string{"/etc/docker/plugins", "/usr/lib/docker/plugins"}
 )
 
+// Registry defines behavior of a registry of plugins.
 type Registry interface {
+	// Plugins lists all plugins.
 	Plugins() ([]*Plugin, error)
+	// Plugin returns the plugin registered with the given name (or returns an error).
 	Plugin(name string) (*Plugin, error)
 }
 
+// LocalRegistry defines a registry that is local (using unix socket).
 type LocalRegistry struct{}
 
 func newLocalRegistry() LocalRegistry {
 	return LocalRegistry{}
 }
 
+// Plugin returns the plugin registered with the given name (or returns an error).
 func (l *LocalRegistry) Plugin(name string) (*Plugin, error) {
 	socketpaths := pluginPaths(socketsPath, name, ".sock")