Fix go lint errors

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

plugin/context.go

@@ -22,11 +22,11 @@ type InitContext struct {
 
 	Meta *Meta // plugins can fill in metadata at init.
 
-	plugins *PluginSet
+	plugins *Set
 }
 
 // NewContext returns a new plugin InitContext
-func NewContext(ctx context.Context, r *Registration, plugins *PluginSet, root, state string) *InitContext {
+func NewContext(ctx context.Context, r *Registration, plugins *Set, root, state string) *InitContext {
 	return &InitContext{
 		Context: log.WithModule(ctx, r.URI()),
 		Root:    filepath.Join(root, r.URI()),
@@ -72,26 +72,26 @@ func (p *Plugin) Instance() (interface{}, error) {
 	return p.instance, p.err
 }
 
-// PluginSet defines a plugin collection, used with InitContext.
+// Set defines a plugin collection, used with InitContext.
 //
 // This maintains ordering and unique indexing over the set.
 //
 // After iteratively instantiating plugins, this set should represent, the
 // ordered, initialization set of plugins for a containerd instance.
-type PluginSet struct {
+type Set struct {
 	ordered     []*Plugin // order of initialization
 	byTypeAndID map[Type]map[string]*Plugin
 }
 
 // NewPluginSet returns an initialized plugin set
-func NewPluginSet() *PluginSet {
-	return &PluginSet{
+func NewPluginSet() *Set {
+	return &Set{
 		byTypeAndID: make(map[Type]map[string]*Plugin),
 	}
 }
 
 // Add a plugin to the set
-func (ps *PluginSet) Add(p *Plugin) error {
+func (ps *Set) Add(p *Plugin) error {
 	if byID, typeok := ps.byTypeAndID[p.Registration.Type]; !typeok {
 		ps.byTypeAndID[p.Registration.Type] = map[string]*Plugin{
 			p.Registration.ID: p,
@@ -107,7 +107,7 @@ func (ps *PluginSet) Add(p *Plugin) error {
 }
 
 // Get returns the first plugin by its type
-func (ps *PluginSet) Get(t Type) (interface{}, error) {
+func (ps *Set) Get(t Type) (interface{}, error) {
 	for _, v := range ps.byTypeAndID[t] {
 		return v.Instance()
 	}

plugin/plugin.go

@@ -58,9 +58,13 @@ const (
 
 // Registration contains information for registering a plugin
 type Registration struct {
-	Type     Type
-	ID       string
-	Config   interface{}
+	// Type of the plugin
+	Type Type
+	// ID of the plugin
+	ID string
+	// Config specific to the plugin
+	Config interface{}
+	// Requires is a list of plugins that the registered plugin requires to be avaliable
 	Requires []Type
 
 	// InitFn is called when initializing a plugin. The registration and
@@ -69,6 +73,7 @@ type Registration struct {
 	InitFn func(*InitContext) (interface{}, error)
 }
 
+// Init the registered plugin
 func (r *Registration) Init(ic *InitContext) *Plugin {
 	p, err := r.InitFn(ic)
 	return &Plugin{