Interface update, per-method Contexts.

service/module/interface.go

 // Copyright 2016 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 package module
 
-// Interface is the interface for all of the package methods which normally
+import (
+        "golang.org/x/net/context"
+)
+
+// RawInterface is the interface for all of the package methods which normally
 // would be in the 'module' package.
-type Interface interface {
+type RawInterface interface {
         List() ([]string, error)
         NumInstances(module, version string) (int, error)
         SetNumInstances(module, version string, instances int) error
         Versions(module string) ([]string, error)
         DefaultVersion(module string) (string, error)
         Start(module, version string) error
         Stop(module, version string) error
 }
+
+// List lists the names of modules belonging to this application.
+func List(c context.Context) ([]string, error) {
+        return Raw(c).List()
+}
+
+// NumInstances returns the number of instances servicing the specified
+// module/version.
+//
+// If module or version is the empty string, it means the default.
+func NumInstances(c context.Context, module, version string) (int, error) {
+        return Raw(c).NumInstances(module, version)
+}
+
+// SetNumInstances sets the number of instances of a given module/version.
+//
+// If module or version is the empty string, it means the default.
+func SetNumInstances(c context.Context, module, version string, instances int) error {
+        return Raw(c).SetNumInstances(module, version, instances)
+}
+
+// Versions returns the names of versions for the specified module.
+//
+// If module is the empty string, it means the default.
+func Versions(c context.Context, module string) ([]string, error) {
+        return Raw(c).Versions(module)
+}
+
+// DefaultVersion returns the name of the default version for the specified
+// module.
+//
+// If module is the empty string, it means the default.
+func DefaultVersion(c context.Context, module string) (string, error) {
+        return Raw(c).DefaultVersion(module)
+}
+
+// Start starts the specified module/version.
+//
+// If module or version is the empty string, it means the default.
+func Start(c context.Context, module, version string) error {
+        return Raw(c).Start(module, version)
+}
+
+// Stop stops the specified module/version.
+//
+// If module or version is the empty string, it means the default.
+func Stop(c context.Context, module, version string) error {
+        return Raw(c).Stop(module, version)
+}