Steps to create API gateway in GCP
1.Creating an API
gcloud beta api-gateway apis create API_ID --project=PROJECT_ID
2.Creating an API config
gcloud beta api-gateway api-configs create CONFIG_ID \
--api=API_ID --openapi-spec=API_DEFINITION \
--project=PROJECT_ID --backend-auth-service-account=SERVICE_ACCOUNT_EMAIL
3.Creating a gateway
gcloud beta api-gateway gateways create GATEWAY_ID \
--api=API_ID --api-config=CONFIG_ID \
--location=GCP_REGION --project=PROJECT_ID