App Engine Flex environment Golang: cannot find module for path io/fs

Question

Every time I deployed a basic Go backend application to the App Engine Flexible environment I get the aforementioned issue.

runtime: go
env: flex

endpoints_api_service:
  # The following values are to be replaced by information from the output of
  # 'gcloud endpoints services deploy openapi-appengine.yaml' command.
  name: YOUR-APP-ID.appspot.com
  rollout_strategy: managed

manual_scaling:
  instances: 1

I tried deploying once and again with a variation of the parameters in the yaml section. But any of them actually worked.

Answer 1

Actually specifying a exact version of the Go runtime makes it work.

runtime_config:
  operating_system: "ubuntu22"
  runtime_version: "1.21"