Simple GAE/goon Context wrapper

go/src/infra/gae/libs/context/context.go

+// Copyright 2015 The Chromium Authors. All rights reserved.

[Vadim Sh., 2015/03/06 02:54:27]

I assume all the permutations are actually used down the road somewhere?

Perhaps you can define only "atomic" interfaces here and define all needed
combinations closer to where they are used?

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// +build appengine
+
+package context
+
+import (
+        "appengine"
+        "appengine/datastore"
+
+        "github.com/mjibson/goon"
+
+        "infra/libs/logging"
+)
+
+/// Kinds + Keys
+
+type Kinder interface {
+        Kind(src interface{}) string
+}
+
+type KindSetter interface {
+        KindNameResolver() goon.KindNameResolver
+        SetKindNameResolver(goon.KindNameResolver)
+}
+
+type NewKeyer interface {
+        NewKey(kind, stringID string, intID int64, parent *datastore.Key) *datastore.Key
+        NewKeyObj(src interface{}) *datastore.Key
+        NewKeyObjError(src interface{}) (*datastore.Key, error)
+}
+
+type KindKeyer interface {
+        Kinder
+        NewKeyer
+}
+
+/// Read + Write
+
+type SingleReadWriter interface {
+        Put(src interface{}) (*datastore.Key, error)
+        Get(dst interface{}) error
+        Delete(key *datastore.Key) error
+}
+
+type MultiReadWriter interface {
+        SingleReadWriter
+        DeleteMulti(keys []*datastore.Key) error
+        GetMulti(dst interface{}) error
+        PutMulti(src interface{}) ([]*datastore.Key, error)
+}
+
+/// Queries
+
+type Queryer interface {
+        Run(q *datastore.Query) Iterator
+        GetAll(q *datastore.Query, dst interface{}) ([]*datastore.Key, error)
+        Count(q *datastore.Query) (int, error)
+}
+
+type Iterator interface {
+        Cursor() (datastore.Cursor, error)
+        Next(dst interface{}) (*datastore.Key, error)
+}
+
+/// Transactions
+
+type Transactioner interface {
+        RunInTransaction(f func(c Context) error, opts *datastore.TransactionOptions) error
+}
+
+/// Abstraction breaking!
+
+type DangerousContexter interface {
+        Context() appengine.Context
+}
+
+type SingleContext interface {
+        logging.Logger
+        Kinder
+        NewKeyer
+        SingleReadWriter
+}
+
+type Context interface {
+        logging.Logger
+        Kinder
+        NewKeyer
+        MultiReadWriter
+        Queryer
+        KindSetter
+}
+
+type TransactionerContext interface {
+        Context
+        Transactioner
+}
+
+type DangerousContext interface {
+        DangerousContexter
+        Context
+}
+
+type DangerousTransactionerContext interface {

[Vadim Sh., 2015/03/06 02:54:27]

nit: maybe "FullContext" or "CompleteContext" or "MaxContext"?..
DangerousTransactionerContext is too long to type. And what if you suddenly need
some new trait similar to "Transactioner" DangerousTransactionerFunnierContext?

+        DangerousContexter
+        TransactionerContext
+}