Googleplay purchases.products.acknowledge return 400 not a valid state and 409 cocurrentUpdate

Question

We try to do acknowledge google play purchase on the server-side through purchases.products.acknowledge with golang

However, the following errors come up sometime

googleapi: Error 409: The operation could not be performed since the object was 
already in the process of being updated., concurrentUpdate

googleapi: Error 400: The purchase is not in a valid state to perform the desired operation

Is there anything am I missing? or how to solve those errors?

Answer 1

Per google support

• For error 400, the purchaseState must be Purchased or 0 before you can acknowledge the purchase. For more information, please refer to this page: https://developer.android.com/google/play/billing/integrate#process

  Error 400 can also mean that you already acknowledged the purchase.

• For error 409, this means you are acknowledging the purchase multiple times concurrently. Unfortunately, we don't provide support for API concurrency issues.