cloudtasks.CreateTask fails: `lacks IAM permission "cloudtasks.tasks.create"` even though my account has that permission

Question

I'm following the Creating HTTP Target tasks guide. When I run the code posted below I get this error:

cloudtasks.CreateTask: rpc error: code = PermissionDenied 
desc = The principal (user or service account)
lacks IAM permission "cloudtasks.tasks.create" for the resource
 "projects/my_project/locations/europe-west1/queues/my_queue" 
(or the resource may not exist).

I have signed in with gcloud auth login my@email.com. my@email.com has the following permissions set by my custom cloud task role:

• cloudtasks.locations.get
• cloudtasks.locations.list
• cloudtasks.queues.get
• cloudtasks.queues.list
• cloudtasks.tasks.create
• cloudtasks.tasks.delete
• cloudtasks.tasks.fullView
• cloudtasks.tasks.get
• cloudtasks.tasks.list
• cloudtasks.tasks.run

I don't get it. What more should I check?

main.go

// Run `PROJECT_ID=my_project QUEUE_ID=my_queue go run main.go`
package main

import (
  "context"
  "fmt"
  "os"

  cloudtasks "cloud.google.com/go/cloudtasks/apiv2"
  taskspb "google.golang.org/genproto/googleapis/cloud/tasks/v2"
)

var (
  locationID = "europe-west1"
  url        = "example.com/callback"
  message    = "testing"
)

func main() {
  projectID := os.Getenv("PROJECT_ID")
  queueID := os.Getenv("QUEUE_ID")

  task, err := createHTTPTask(projectID, locationID, queueID, url, message)
  if err != nil {
    fmt.Println(err)
  }
  fmt.Println(task)
}

// createHTTPTask creates a new task with a HTTP target then adds it to a Queue.
func createHTTPTask(projectID, locationID, queueID, url, message string) (*taskspb.Task, error) {
  // Create a new Cloud Tasks client instance.
  // See https://godoc.org/cloud.google.com/go/cloudtasks/apiv2
  ctx := context.Background()
  client, err := cloudtasks.NewClient(ctx)
  if err != nil {
    return nil, fmt.Errorf("NewClient: %v", err)
  }
  // Build the Task queue path.
  queuePath := fmt.Sprintf("projects/%s/locations/%s/queues/%s", projectID, locationID, queueID)
  // Build the Task payload.
  // https://godoc.org/google.golang.org/genproto/googleapis/cloud/tasks/v2#CreateTaskRequest
  req := &taskspb.CreateTaskRequest{
    Parent: queuePath,
    Task: &taskspb.Task{
      // https://godoc.org/google.golang.org/genproto/googleapis/cloud/tasks/v2#HttpRequest
      MessageType: &taskspb.Task_HttpRequest{
        HttpRequest: &taskspb.HttpRequest{
          HttpMethod: taskspb.HttpMethod_POST,
          Url:        url,
        },
      },
    },
  }
  // Add a payload message if one is present.
  req.Task.GetHttpRequest().Body = []byte(message)
  createdTask, err := client.CreateTask(ctx, req)
  if err != nil {
    return nil, fmt.Errorf("cloudtasks.CreateTask: %v", err)
  }
  return createdTask, nil
}

The Cloud Tasks API is enabled.

Answer 1

I've been having the same issue for the past couple of days and figured it out. The library I was using to create the API client and create a task was using different credentials than I expected.

For those that are using "application default credentials", or at least letting the client find credentials automatically, take a look at this page: https://cloud.google.com/docs/authentication/production#finding_credentials_automatically

I had created a service account with all the right roles and was assuming the API client was using the service account. Turns out I wasn't passing in the key file and thus it was using the "application default credentials". For my use case, "application default credentials" referred to the App Engine default service account. When I supplied the API client with a key file for my custom service account, it worked.