Terraform on GCP fails to create pubsub topic stating permission denied - google-cloud-platform

Question

Created a service user to manage terraform under the project and gave it roles/owner. Created the key for this terraform user.
Terraform code is simple:
resource "google_pubsub_topic" "my_topic" {
name = "my_topic"
project = "${var.project_id}"
}
just creating a pub-sub topic.
terraform plan works but terraform apply gives me:
google_pubsub_topic.my_topic: googleapi: Error 403: User not authorized to perform this action., forbidden
I have even tried giving the service account roles/pubsub.admin not sure I understand what's going on because my service account has the owner role associated with it yet it can't create a pubsub topic.
Can anybody help me figure this out please?
Thanks in advance.
Edit (to expand on my comment about what worked):
I had created the service account using gcloud.
gcloud iam service-accounts create terraform \
--display-name "Terraform admin account"
gcloud projects add-iam-policy-binding myproject-182220 \
--member serviceAccount:terraform#myproject-182220.iam.gserviceaccount.com \
--role roles/owner
gcloud iam service-accounts keys create terraform-admin.json \
--iam-account terraform#myproject-182220.iam.gserviceaccount.com
To continue my debugging, I created a new service account using the console / GUI --> API & Services --> Credentials --> Create Credentials --> Service Account Key --> New Service Account (With the owner role). With this new service key json file, I was able to run my terraform code without a problem.
Now my confusion is, why did this work but not when I used gcloud to create a service account and give it the same role?

Answer 1

You have to enable the pub/sub api via google cloud or it might be possible using terraform.

Answer 2

The sample usage configuration for the Google provider looks more like:
// Configure the Google Cloud provider
provider "google" {
credentials = "${file("account.json")}"
project = "my-gce-project"
region = "us-central1"
}
// Create a new instance
resource "google_compute_instance" "default" {
# ...
}
This can be read in more detail on the "Google Cloud Provider" documentation page from Terraform.