Add TrimmedAppID to info service.

service/info/interface.go

 // Copyright 2015 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 info
 
 import (
         "time"
 
         "golang.org/x/net/context"
 )
 
-// Interface is the interface for all of the package methods which normally
+// RawInterface is the interface for all of the package methods which normally
 // would be in the 'appengine' package.
-type Interface interface {
+type RawInterface interface {
         AppID() string
         FullyQualifiedAppID() string
         GetNamespace() (string, bool)
 
         Datacenter() string
         DefaultVersionHostname() string
         InstanceID() string
         IsDevAppServer() bool
         IsOverQuota(err error) bool
         IsTimeoutError(err error) bool
         ModuleHostname(module, version, instance string) (string, error)
         ModuleName() string
         RequestID() string
         ServerSoftware() string
         ServiceAccount() (string, error)
         VersionID() string
 
         Namespace(namespace string) (context.Context, error)
-        MustNamespace(namespace string) context.Context
 
         AccessToken(scopes ...string) (token string, expiry time.Time, err error)
         PublicCertificates() ([]Certificate, error)
         SignBytes(bytes []byte) (keyName string, signature []byte, err error)
 
         // Testable returns this Interface's Testable interface. Testing will return
         // nil if testing is not supported in this implementation.
         Testable() Testable
 }
 
+// Interface is the interface for all of the package methods which normally
+// would be in the 'appengine' package. This version adds a couple helper
+// functions on top of the RawInterface.
+type Interface interface {
+        RawInterface
+
+        // TrimmedAppID gets the 'appid' portion of "foo.com:appid". This form can
+        // occur if you use
+        TrimmedAppID() string
+
+        // MustNamespace is the same as Namespace, but will panic if there's an error.
+        // Since an error can only occur if namespace doesn't match the a regex this
+        // is valid to use if the namespace you're using is statically known, or known
+        // to conform to the regex. The regex in question is:
+        //
+        //   ^[0-9A-Za-z._-]{0,100}$
+        MustNamespace(namespace string) context.Context
+}
+
 // Testable is an additional set of functions for testing instrumentation.
 type Testable interface {
         SetVersionID(string) context.Context
         SetRequestID(string) context.Context
 }