open-nomad/vendor/google.golang.org/appengine/datastore/keycompat.go
Seth Hoenig 435c0d9fc8 deps: Switch to Go modules for dependency management
This PR switches the Nomad repository from using govendor to Go modules
for managing dependencies. Aspects of the Nomad workflow remain pretty
much the same. The usual Makefile targets should continue to work as
they always did. The API submodule simply defers to the parent Nomad
version on the repository, keeping the semantics of API versioning that
currently exists.
2020-06-02 14:30:36 -05:00

90 lines
2.5 KiB
Go

// Copyright 2019 Google Inc. All rights reserved.
// Use of this source code is governed by the Apache 2.0
// license that can be found in the LICENSE file.
package datastore
import (
"sync"
"golang.org/x/net/context"
"google.golang.org/appengine/datastore/internal/cloudkey"
"google.golang.org/appengine/internal"
)
var keyConversion struct {
mu sync.RWMutex
appID string // read using getKeyConversionAppID
}
// EnableKeyConversion enables encoded key compatibility with the Cloud
// Datastore client library (cloud.google.com/go/datastore). Encoded keys
// generated by the Cloud Datastore client library will be decoded into App
// Engine datastore keys.
//
// The context provided must be an App Engine context if running in App Engine
// first generation runtime. This can be called in the /_ah/start handler. It is
// safe to call multiple times, and is cheap to call, so can also be inserted as
// middleware.
//
// Enabling key compatibility does not affect the encoding format used by
// Key.Encode, it only expands the type of keys that are able to be decoded with
// DecodeKey.
func EnableKeyConversion(ctx context.Context) {
// Only attempt to set appID if it's unset.
// If already set, ignore.
if getKeyConversionAppID() != "" {
return
}
keyConversion.mu.Lock()
// Check again to avoid race where another goroutine set appID between the call
// to getKeyConversionAppID above and taking the write lock.
if keyConversion.appID == "" {
keyConversion.appID = internal.FullyQualifiedAppID(ctx)
}
keyConversion.mu.Unlock()
}
func getKeyConversionAppID() string {
keyConversion.mu.RLock()
appID := keyConversion.appID
keyConversion.mu.RUnlock()
return appID
}
// decodeCloudKey attempts to decode the given encoded key generated by the
// Cloud Datastore client library (cloud.google.com/go/datastore), returning nil
// if the key couldn't be decoded.
func decodeCloudKey(encoded string) *Key {
appID := getKeyConversionAppID()
if appID == "" {
return nil
}
k, err := cloudkey.DecodeKey(encoded)
if err != nil {
return nil
}
return convertCloudKey(k, appID)
}
// convertCloudKey converts a Cloud Datastore key and converts it to an App
// Engine Datastore key. Cloud Datastore keys don't include the project/app ID,
// so we must add it back in.
func convertCloudKey(key *cloudkey.Key, appID string) *Key {
if key == nil {
return nil
}
k := &Key{
intID: key.ID,
kind: key.Kind,
namespace: key.Namespace,
parent: convertCloudKey(key.Parent, appID),
stringID: key.Name,
appID: appID,
}
return k
}