datastore error - not an App Engine contex

[cn0047]

I'm trying to upgrade my project from go1 to go111.
In my project I'm using datastore, here you can see how my code looks:

package controller

import (
	"google.golang.org/appengine/datastore"
	"log"
	"net/http"
	"time"
)

type Measurement struct {
	Project      string    `datastore:"project"`
	At           time.Time `datastore:"at"`
	Took         int       `datastore:"took,noindex"`
	ResponseCode int       `datastore:"responseCode"`
}

func MeasurementController(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()

	query := datastore.NewQuery("Measurement")
	data := make([]Measurement, 0)

	keys, err := query.GetAll(ctx, &data)
	if err != nil {
		log.Printf("Error %#v", err)
		return
	}

	log.Printf("Keys: %+v, Data: %+v", keys, data)
}

And I always get error: Error: &errors.errorString{s:"not an App Engine context"}
As you can see I've already replaced ctx := appengine.NewContext(r) to ctx := r.Context()
but it won't work.

[sbuss]

Can you verify that you've upgraded to the latest google.golang.org/appengine package?

[cn0047]

Yes, my google.golang.org/appengine version is v1.2.0.

[jhaals]

I've got the same error using appengine.NewContext(r) with memcache. Version v1.2.0

[sinmetal]

Are you calling `appengine.Main()` ? package main import ( "net/http" "google.golang.org/appengine" ) func main() { http.HandleFunc("/", handler) appengine.Main() } https://cloud.google.com/appengine/docs/standard/go111/go-differences#writing_a_main_package Only when appengine.Main() is executed, it injects appengine.Context into request. https://github.com/golang/appengine/blob/ae0ab99deb4dc413a2b4bd6c8bdd0eb67f1e4d06/internal/api.go#L93 2018年10月24日(水) 22:26 Johan Haals <notifications@github.com>:

…

I've got the same error using appengine.NewContext(r) with memcache. Version v1.2.0 — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#167 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAbORp5ZAsML5quTo6gcvdGyL8OPXGsHks5uoGpngaJpZM4X0EEv> .

[cn0047]

I've put back appengine.Main() and now all works.
Thank you @sinmetal!

[sbuss]

Thanks for the suggestion, @sinmetal!

As long as you are using google.golang.org/appengine you need to include that call to appengine.Main(). It sets up some connections to internal Google App Engine services necessary for the package to work. If you are just using regular go cloud packages, you don't need it.