Attempting to subscribe to a Shopify Webhook w/AWS EventBridge produces error: "Address is an AWS ARN and includes api_client_id 'x' instead of 'y'" - shopify

Question

I'm running this request through Postman. Some posts to the Shopify developer forum (e.g., this one) express without clear explanation that the request should be made within the Shopify app that would be subscribing to the Webhooks, but Postman seems to work, too.
In Postman . . .
Here's the endpoint:
https://{{shopifyDevelopmentStoreName}}.myshopify.com/admin/api/2022-07/graphql.json
Here's the GraphQL body:
mutation createWebhookSubscription($topic: WebhookSubscriptionTopic!, $webhookSubscription: EventBridgeWebhookSubscriptionInput!) {
eventBridgeWebhookSubscriptionCreate(
topic: $topic,
webhookSubscription: $webhookSubscription
) {
webhookSubscription {
id
}
userErrors {
message
}
}
}
Here's the payload being sent (notice the "client_id_x" value within the arn property):
{
"topic": "PRODUCTS_CREATE",
"webhookSubscription": {
"arn": "arn:aws:events:us-east-1::event-source/aws.partner/shopify.com/client_id_x/LovecraftEventBridgeSource",
"format": "JSON",
"includeFields": "id"
}
}
Here's the response I receive:
{
"data": {
"eventBridgeWebhookSubscriptionCreate": {
"webhookSubscription": null,
"userErrors": [
{
"message": "Address is invalid"
},
{
"message": "Address is an AWS ARN and includes api_client_id 'client_id_x' instead of 'client_id_y'"
}
]
}
},
"extensions": {
"cost": {
"requestedQueryCost": 10,
"actualQueryCost": 10,
"throttleStatus": {
"maximumAvailable": 1000.0,
"currentlyAvailable": 990,
"restoreRate": 50.0
}
}
}
}
What's entirely unclear is why Shopify is insisting upon validity of "client_id_y" when, in AWS, the value being displayed is undeniably 'client_id_x'. Extremely confusing. I don't even see what difference using the Shopify app would make except that it produces a client_id value that works counter to one's expectations and intuitions.
Does anyone know why the heck Shopify isn't just using the client_id value of the event bus created earlier in Amazon EventBridge?

Answer 1

Same happend to me and I was lucky to find a solution.
The error message is just missleading.
I replaced the API Access Token for the Shopify Rest API Request (X-Shopify-Access-Token)
with the one from the Shopify App holding the aws credentials.
admin/settings/apps/development -> app -> API credentials -> Admin API access token. (can only be seen after creation)
Then I could subscribe webhooks to the app via the Rest Interface.