mirror of
https://github.com/golang/go
synced 2024-11-19 00:24:41 -07:00
707c7629cb
LGTM=dsymonds R=golang-codereviews, dsymonds CC=golang-codereviews https://golang.org/cl/104780044
65 lines
1.4 KiB
Go
65 lines
1.4 KiB
Go
// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build appengine
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package key
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import (
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"sync"
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"appengine"
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"appengine/datastore"
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)
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var theKey struct {
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sync.RWMutex
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builderKey
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}
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type builderKey struct {
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Secret string
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}
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func (k *builderKey) Key(c appengine.Context) *datastore.Key {
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return datastore.NewKey(c, "BuilderKey", "root", 0, nil)
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}
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func Secret(c appengine.Context) string {
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// check with rlock
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theKey.RLock()
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k := theKey.Secret
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theKey.RUnlock()
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if k != "" {
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return k
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}
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// prepare to fill; check with lock and keep lock
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theKey.Lock()
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defer theKey.Unlock()
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if theKey.Secret != "" {
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return theKey.Secret
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}
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// fill
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if err := datastore.Get(c, theKey.Key(c), &theKey.builderKey); err != nil {
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if err == datastore.ErrNoSuchEntity {
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// If the key is not stored in datastore, write it.
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// This only happens at the beginning of a new deployment.
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// The code is left here for SDK use and in case a fresh
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// deployment is ever needed. "gophers rule" is not the
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// real key.
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if !appengine.IsDevAppServer() {
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panic("lost key from datastore")
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}
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theKey.Secret = "gophers rule"
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datastore.Put(c, theKey.Key(c), &theKey.builderKey)
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return theKey.Secret
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}
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panic("cannot load builder key: " + err.Error())
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}
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return theKey.Secret
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}
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