aedatastore

Documentation

Overview

Package aedatastore provides AppEngine Datastore implementation of datastore.Client. This package wrapping google.golang.org/appengine/datastore package.

Index

• func FromContext(ctx context.Context, opts ...w.ClientOption) (w.Client, error)
• func IsAEDatastoreClient(client w.Client) bool
• func TransactionContext(tx w.Transaction) context.Context

Examples

• FromContext
• TransactionContext

Functions

func FromContext

func FromContext(ctx context.Context, opts ...w.ClientOption) (w.Client, error)

FromContext make new Client by specified context.

Example

package main

import (
	"fmt"

	"go.mercari.io/datastore/aedatastore"
	"google.golang.org/appengine"
	"google.golang.org/appengine/aetest"
)

func main() {
	inst, err := aetest.NewInstance(&aetest.Options{StronglyConsistentDatastore: true, SuppressDevAppServerLog: true})
	if err != nil {
		panic(err)
	}
	defer inst.Close()
	r, err := inst.NewRequest("GET", "/", nil)
	if err != nil {
		panic(err)
	}
	ctx := appengine.NewContext(r)

	client, err := aedatastore.FromContext(
		ctx,
	)
	if err != nil {
		panic(err)
	}
	defer client.Close()

	type Data struct {
		Name string
	}

	key := client.IncompleteKey("Data", nil)
	entity := &Data{Name: "mercari"}
	key, err = client.Put(ctx, key, entity)
	if err != nil {
		panic(err)
	}

	entity = &Data{}
	err = client.Get(ctx, key, entity)
	if err != nil {
		panic(err)
	}

	fmt.Println(entity.Name)
}

Output:

mercari

func IsAEDatastoreClient

func IsAEDatastoreClient(client w.Client) bool

IsAEDatastoreClient returns check result that client is this package's client or not.

func TransactionContext

func TransactionContext(tx w.Transaction) context.Context

TransactionContext returns context that is under the AppEngine Datastore's transaction.

Example

package main

import (
	"context"
	"net/url"

	"go.mercari.io/datastore/aedatastore"
	"google.golang.org/appengine"
	"google.golang.org/appengine/aetest"
	"google.golang.org/appengine/taskqueue"
)

func appengineContext() (ctx context.Context, cancelFn func() error) {
	inst, err := aetest.NewInstance(&aetest.Options{StronglyConsistentDatastore: true, SuppressDevAppServerLog: true})
	if err != nil {
		panic(err)
	}
	cancelFn = inst.Close
	r, err := inst.NewRequest("GET", "/", nil)
	if err != nil {
		panic(err)
	}
	ctx = appengine.NewContext(r)

	return
}

func main() {
	ctx, cancelFn := appengineContext()
	go cancelFn()

	client, err := aedatastore.FromContext(ctx)
	if err != nil {
		panic(err)
	}
	defer client.Close()

	tx, err := client.NewTransaction(ctx)
	if err != nil {
		panic(err)
	}
	go tx.Commit()

	txCtx := aedatastore.TransactionContext(tx)

	// join task to Transaction!
	task := taskqueue.NewPOSTTask("/foobar", url.Values{})
	_, err = taskqueue.Add(txCtx, task, "")
	if err != nil {
		panic(err)
	}
}